technetium-tc-99m-exametazime and Cerebrovascular-Disorders

Brain SPECT studies are used to evaluate the cerebral hemodynamic changes in cerebrovascular diseases and other neuro-psychiatric disorders. I-123 and Tc-99m labeled radiopharmaceuticals widely used for brain perfusion SPECT studies include I-123 IMP, Tc-99m HMPAO, and Tc-99m ECD. I-123 IMP is suitable for the quantitative evaluation of cerebral blood flow, while Tc-99m HMPAO and Tc-99m ECD have problems owing to the non-linearity between cerebral radioactivity and cerebral blood flow. In addition, Tc-99m ECD does not show cerebral blood flow in the subacute phase of cerebral infarct or other conditions. Thus, it is important to consider the characteristics of radiopharmaceuticals and the clinical aspect of brain lesions in the interpretation of brain perfusion SPECT images. In this review, some useful information on brain perfusion SPECT is presented mainly as it relates to the cerebrovascular diseases.

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Cysteine; Humans; Iofetamine; Mental Disorders; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To reliably identify patients at risk for symptomatic hemorrhagic transformation (SHT), future trials of thrombolysis for acute ischemic stroke might use a vascular imaging protocol applicable to a multicenter setting. The goal of this commentary is to address the safety of intravenous thrombolysis with the recombinant tissue plasminogen activator (rTPA) and potential solutions offered by single-photon emission CT (SPECT) as a noninvasive brain perfusion imaging modality.. Even if patients with severe stroke, extensive ischemic changes on CT scan, advanced age, and high blood pressure are excluded from thrombolytic therapy, this cannot completely guarantee the safety of using rTPA. Brain SPECT scanning with hexamethylpropyleneamine-oxime (HMPAO) may help to screen out patients at risk if performed in addition to clinical and CT tests. The knowledge of pretreatment severity, extent, and location of ischemia might identify good versus poor responders to rTPA therapy. HMPAO-SPECT is widely available and feasible to perform without delaying rTPA therapy. Rigorous quality control and use of reproducible visual and semiquantitative methods of interpreting SPECT are necessary for implementation of SPECT technology in multicenter clinical trials.. The major obstacle to general acceptance of thrombolytic therapies and rTPA in particular is the fear of symptomatic hemorrhagic transformation, and because HMPAO-SPECT might reliably identify patients at high risk of symptomatic hemorrhagic transformation, the clinical value of HMPAO-SPECT in patient selection for thrombolysis during the first hours of acute ischemic stroke should be determined through a prospective clinical trial.

Topics: Acute Disease; Brain; Brain Ischemia; Cerebrovascular Disorders; Humans; Nuclear Medicine; Organotechnetium Compounds; Oximes; Safety; Societies, Medical; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Isomerism; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tissue Distribution; Tomography, Emission-Computed, Single-Photon

The imaging of regional cerebral blood flow (rCBF) by 99mTc-d, 1 HM-PAO and SPECT is described. Its relevance to clinical syndromes, such as stroke, transient ischemic attacks, various forms of dementia, epilepsy, and subarachnoid hemorrhage, is reported.

Topics: Animals; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Chemical Phenomena; Chemistry; Dementia; Epilepsy; Humans; Ischemic Attack, Transient; Organometallic Compounds; Organotechnetium Compounds; Oximes; Subarachnoid Hemorrhage; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Sildenafil citrate is widely used for erectile dysfunction. The present study examined the short-term effects of sildenafil administration in individuals with cerebrovascular risk factors, including patients with a history of stroke.. Twenty-five consecutive male patients with erectile dysfunction and vascular risk factors were included in the study. A perfusion brain SPECT study was performed at baseline and 1 h after the oral administration of sildenafil.. Associations between any of the risk factors and the perfusion scores were not detected, with the exception of stroke. Stroke patients showed significantly more areas with diminished perfusion after sildenafil administration compared to baseline.. In patients with diabetes or hypertension, a dose of 50 mg sildenafil does not appear to produce detrimental effects on cerebral blood flow. However, patients with a history of stroke may be at increased risk of hemodynamic impairment after the use of sildenafil.

Topics: Adult; Aged; Brain Mapping; Cerebrovascular Circulation; Cerebrovascular Disorders; Erectile Dysfunction; Humans; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Purines; Radiopharmaceuticals; Risk Factors; Sildenafil Citrate; Sulfones; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cerebral blood flow (CBF) can be quantified non-invasively using the brain perfusion index (BPI), which is determined using radionuclide angiographic data obtained through the use of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO). The BPI is generally calculated using graphical analysis (GA). In this study, BPI was measured using spectral analysis (SA), and the usefulness of SA was compared with that of GA. Thirteen patients with various brain diseases and four healthy male volunteers were examined using radionuclide angiography with 99mTc-HMPAO. The BPI was measured for each subject using both SA and GA. In the four healthy volunteers, the BPI was examined at rest and after the intravenous administration of 1 g of acetazolamide (ACZ). An H2(15)O PET examination was also performed in the 13 patients; the BPIS and BPIG values were compared with the CBF measurements obtained using H2(15)O PET (CBFPET). The BPI values obtained by SA (BPIS) (x) and by GA (BPIG) (y) were correlated (y = 0.568x + 0.055, r = 0.901) in the 13 patients and four healthy volunteers at rest, although the BPIG values were underestimated by 36.1 +/- 7.5% (mean +/- SD) compared with the BPIS values. The degree of underestimation tended to increase with increasing BPIS values. The increase in the BPIS was 32.1 +/- 8.0% after the intravenous administration of ACZ, while the increase in BPIG was only 8.1 +/- 2.8%. This discrepancy was considered to be the result of the BPIG values being affected by the first-pass extraction fraction of the tracer. Although both BPIS and BPIG values were significantly correlated with the CBFPET values, the correlation coefficient for BPIS was higher than that for BPIG (BPIS: r = 0.881; BPIG: r = 0.832). These results suggest that SA produces a more reliable BPI for quantifying CBF using 99mTc-HMPAO than the conventional method using GA. The SA method should be especially useful for activation studies involving pharmacological intervention and/or clinical cases with an increased CBF.

Topics: Adult; Aged; Algorithms; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Oxygen Radioisotopes; Positron-Emission Tomography; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Water

The aim of our study was twofold: to determine the frequency and magnitude of perfusion defect in stroke patients who qualify for rtPA therapy within 3 hours of stroke onset and to determine the ability of rtPA to improve perfusion by 24 hours.. Patients with suspected hemispheric stroke who fulfilled entry criteria into the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Study and also had pretreatment injection of (99m)Tc-HMPAO, with single-photon emission computed tomography (SPECT) performed using a triple-head camera at baseline and 24 hours, were included.. All 12 patients who qualified for rtPA therapy had perfusion defects on baseline SPECT (SPECT graded scale [SGS] score range, 16 to 79). Mean+/-SD perfusion defect was comparable in rtPA (n=4)versus placebo (n=5) groups (SGS score, 36+/-18 versus 39+/-12; NS) despite earlier injection time in the rtPA group (98+/-24 versus 141+/-21 minutes; P=.02). Total SPECT scanning time was 20 to 25 minutes. At 24 hours, reperfusion was greater in rtPA patients compared with the placebo group (SGS score, 7+/-9 versus 29+/-17; P=.05), with relative improvement in the region-of-interest scores of 87+/-16% after rtPA compared with 28+/-30% with placebo (P=.01).. A substantial perfusion defect exists in stroke patients with larger hemispheric infarcts who meet NINDS criteria for rtPA therapy, and rtPA is better able than placebo to rectify this defect. SPECT is feasible for clinical trials and should be evaluated as a substituted end point in stroke therapeutic trials.

Topics: Cerebrovascular Disorders; Humans; Patient Selection; Placebos; Plasminogen Activators; Radiopharmaceuticals; Recombinant Proteins; Reperfusion; Technetium Tc 99m Exametazime; Time Factors; Tissue Plasminogen Activator; Tomography, Emission-Computed, Single-Photon

Magnetic resonance imaging (MRI) and computed tomography (CT) may not be reliable in the differential diagnosis of tumour necrosis, scar and recurrent tumour. We compared 201Tl-chloride SPET with CT and MRI for the differential diagnosis of these cerebral lesions. Brain SPET was performed in 40 patients after the intravenous injection of 201Tl-chloride. All 40 patients also had a CT or MRI scan, and a histological diagnosis was available for 27 of the patients. For each patient, the ratio of counts in the lesion region of interest (ROI) to counts in the contralateral ROI was calculated and found to be between 0.58 and 9.60. The ratios for high-grade gliomas, metastases and meningiomas were high (> 2.7), especially in tumours with good vascularization. A low ratio (< 1.7) was noted in patients with low-grade astrocytoma, necrosis or ischaemic lesions. There were two exceptional cases of ischaemic lesions in the luxury perfusion stage (ratios of 3.61 and 3.87), as verified by HMPAO-SPET. We found that 201Tl-chloride SPET helps to differentiate between malignant tumours, poorly vascularized benign lesions and necrosis. Differentiation between low-grade astrocytoma and non-malignant lesions was not possible, but there was a trend towards differentiating between low-grade astrocytoma and ischaemic infarction. The timing of the investigation is important to avoid false-positive results in hyperperfused ischaemic tissue.

Topics: Adult; Aged; Brain Neoplasms; Cerebrovascular Disorders; Diagnosis, Differential; Female; Functional Laterality; Gamma Cameras; Humans; Male; Middle Aged; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Although a sequential 99mTc-HMPAO SPECT technique with Diamox test (seq-SPECT) is a simple and time-saving procedure to assess brain perfusion reserve, the influence of the first dose of the tracer on the second one is not negligible. Therefore, a subtraction of the rest-SPECT from the 2nd SPECT is widely-used. However, subtracted SPECT images not only need to be corrected for the injected dose and the radiochemical purity due to inherent instability of HMPAO but also are usually degraded in quality. This study was undertaken to resolve these problems utilizing a change ratio (CR) map. The CR map was obtained by dividing 2nd SPECT by rest-SPECT. Prior to subtraction, the 2nd SPECT was normalized with the ratio of the mean whole brain counts between both SPECTs. To validate CR map, 7 patients were studied with both seq-SPECT and 133Xe inhalation CBF measurement (Xe-CBF). The right to left count ratio obtained from the ROIs placed on MCA territory of CR map correlated well with that from Xe-CBF (r = 0.89, p < 0.01). Fifty-three patients with stroke underwent the seq-SPECT which was compared with the cerebral angiography (CAG) and classified into 4 groups according to the CR map. In 25 patients, all of the rest-, the subtracted-SPECT and the CR map did not show any difference between the affected side and the contralateral normal side. Seven patients with normal rest-SPECT showed decreased subtracted-SPECT counts and CR on the affected side. Three of them showed more than 75% stenosis on CAG. Four patients with the decreased counts both at the rest- and the subtracted-SPECT revealed no difference on the CR map suggesting the matched decrease of both blood flow and metabolism in the affected side. In conclusion, the CR map was a simple and useful method to evaluate the brain perfusion reserve with the seq-SPECT.

Topics: Acetazolamide; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Chronic Disease; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Recent acute stroke trials have reported that intravenous streptokinase is associated with an increased risk of adverse outcomes. We aimed to study the effect of streptokinase on the nature of reperfusion and the relation between reperfusion and clinical outcome.. We studied 24 patients in the Australian Streptokinase Trial with acute middle cerebral cortical infarction using 99mTc-hexamethylpropyleneamine oxime single-photon emission CT. Eleven of the 24 patients were scanned before therapy and again 24 hours later. The remaining 13 were scanned once either before therapy (1 patient) or after therapy (12 patients). All patients had outcome scans after 3 months. Infarct hypoperfusion was measured with a validated volumetric technique. Neurological impairment and functional outcome were assessed with the Canadian Neurological Scale and the Barthel Index, respectively.. Fifteen patients received streptokinase and 9 received placebo. There was no difference in early reperfusion between streptokinase and placebo. However, streptokinase was associated with a greater amount of nonnutritional reperfusion than was placebo (P = .04). This luxury perfusion was associated with poor functional outcome (P = .02).. This study suggests that streptokinase augments luxury perfusion after stroke. Luxury perfusion is associated with a worse outcome, which might be due in part to reperfusion injury.

Topics: Adult; Aged; Aged, 80 and over; Cerebral Hemorrhage; Cerebral Infarction; Cerebrovascular Circulation; Cerebrovascular Disorders; Cohort Studies; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Streptokinase; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

In 53 patients with chronic occlusive cerebrovascular diseases, we evaluated cerebral perfusion reserve. Cerebral perfusion reserve was evaluated by the change in cerebral blood flow (CBF) at rest and the CBF after acetazolamide (Diamox) as measured by the 133Xe gas inhalation SPECT method. Crossed cerebellar diaschisis (CCD) was evaluated semiquantitatively by the count ratio of the cerebellar cortex using 99mTc-HMPAO SPECT. Thirty-two (49%) of the 65 affected lesions in 53 patients had shown a decreased response to Diamox. In the cases of decreased response to Diamox, the response improved significantly after surgery. However, CBF did not improve as much as the response. In the 40 nonaffected sides, 21 (53%) showed decreased CBF at rest but good response to Diamox. At rest, no difference of the CBF ratio (affected/contralateral nonaffected cerebral cortex) was observed between the patients with CCD (6 pts) and those without CCD (8 pts). After Diamox, however, the CBF ratio of the patients with CCD was significantly higher than that without CCD. The change of the CBF ratio before and after Diamox correlated significantly with the degree of CCD (r = -0.794, p < 0.01). Diamox was useful for evaluating the cerebral perfusion reserve to indicate surgery in patients with chronic cerebrovascular diseases. Perhaps CCD could be a useful index in the differentiation of the decreased CBF caused by reduced perfusion pressure from that caused by reduced metabolic demand because CCD had a close relationship with the cerebral perfusion reserve.

Topics: Acetazolamide; Adult; Aged; Brain; Cerebellar Diseases; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon Radioisotopes

51 patients with cerebral microangiopathy were studied with MRI, 18FDG-PET, and 99mTc-HMPAO-SPECT. Exact morphological correlation of MRI-findings to functional data from PET and SPECT was obtained by a special head holder system applied to the patient's head. Patients with less than four lacunar infarctions (LI) and without or only slight deep white matter lesions (DWML) in MRI showed no significantly changed parameters (rMRGlu, rCBF) compared to patients with four or more LI and severe DWML. Patients with medium to severe outer and inner brain atrophy showed significantly lower rMRGlu and rCBF values in both cortex and white matter than patients with no to only slight atrophy. Thus, in patients with cerebral microangiopathy only atrophy and not the presence of LI and DWML is associated with a significant reduction of rCBF and rMRGlu.

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Deoxyglucose; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Organ Specificity; Organotechnetium Compounds; Oximes; Perfusion; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

rCBF SPECT with 99mTc-HMPAO was performed prospectively in 29 patients (3 controls and 26 stroke patients) as well as TCD studies in 20 patients (3 controls and 17 stroke patients) before and after 1 g i.v. acetazolamide. The sensitivity of rCBF SPECT increased from 62% to 77% after acetazolamide provocation in stroke patients. In patients with a reversible neurological deficit, the sensitivity under resting conditions was 50% which increased to 71%, while in cases with a permanent deficit it increased from 75% to 83%. In the evaluation of the cerebrovascular reserve capacity the results of rCBF SPECT and TCD coincided in 91% of the hemispheres. The correlation was statistically significant.

Topics: Acetazolamide; Adult; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Echoencephalography; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prospective Studies; Reference Values; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Ultrasonography, Doppler, Transcranial

Anticardiolipin antibodies (ACA) belong to a heterogeneous group of antibodies directed against negatively charged phospholipids. In patients with rheumatic disorders, their presence has been correlated to the occurrence of thromboembolic complications, thrombocytopenia, abortions and other disease manifestations. Several studies have revealed the detection of mostly high-titre ACA in a significant proportion of HIV-infected patients without any known clinical relationship. In our study, ACA were detected in 17/34 HIV-infected patients, and their presence was significantly associated with the detection of cerebral perfusion abnormalities by 99mTc-HMPAO SPECT. SPECT scans were classified as normal or as focal or diffuse defects in uptake. Most patients (13/16) with cerebral perfusion defects had elevated ACA titres in contrast to 4/18 patients with normal SPECT findings (P = 0.002). Focal uptake defects were always associated with the presence of ACA. No correlation to clinical features or other laboratory parameters was evident. Our results suggest a possible implication of autoimmune mechanisms in the pathogenesis of cerebral perfusion abnormalities detected by SPECT scanning in HIV-infected patients. However, further studies are needed to evaluate the clinical significance and to develop possible therapeutic consequences.

Topics: Adult; AIDS-Related Opportunistic Infections; Antibodies, Anticardiolipin; Antigen-Antibody Complex; Autoimmunity; beta 2-Microglobulin; Biopterins; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; HIV Infections; Humans; Immunoglobulins; Male; Middle Aged; Neopterin; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Thrombocytopenia; Tomography, Emission-Computed, Single-Photon

We used 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography (SPECT) to study cerebral perfusion in patients treated with streptokinase for acute ischemic stroke in an open and prospective study. Our primary aims were (1) to compare the extent of reperfusion between patients who had received thrombolytic therapy and a control group studied during the same period who were ineligible to receive such therapy and (2) to determine if, among all patients, reperfusion led to improved outcome.. Fifty-seven patients (22 treated with streptokinase) had two SPECT studies performed, the first before streptokinase administration and the second 24 hours later.. On the first SPECT study hyperfusion was present in the middle cerebral artery or anterior cerebral artery territories in 40 patients (17 treated with streptokinase). Patients in the treatment and control groups with initial hypoperfusion on SPECT were well matched for the volume of the perfusion defect and the severity of neurological deficit. A greater number of patients who received streptokinase developed at least partial reperfusion (streptokinase, 65%; control, 52%) on the second study but not significantly so (P = .43). Similarly, the proportion of each hypoperfused region that reperfused (P = .74) and the reduction in the size of the perfusion defect (P = .06) were higher in the streptokinase group but did not reach statistical significance. When all patients were considered, those who did not reperfuse had higher mortality rates (P = .008), less neurological improvement (P = .016), and more functional disability (P < .001) than patients who had reperfusion or normal perfusion initially.. These findings suggest that at least some reperfusion during the first 48 hours of ischemic stroke is a common natural occurrence and is of prognostic significance. The observed trend toward better reperfusion indexes among patients treated with streptokinase is encouraging, but larger controlled trials are required to answer this definitively.

Topics: Aged; Brain Ischemia; Cerebral Angiography; Cerebrovascular Disorders; Female; Humans; Male; Nervous System; Organotechnetium Compounds; Oximes; Pilot Projects; Reperfusion; Streptokinase; Subtraction Technique; Survival Analysis; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

A phase 3 clinical study of a newly developed brain perfusion agent, 99mTc-L,L-ethyl cysteinate dimer (99mTc-ECD), was performed in 521 cases of cerebrovascular diseases and impairment of brain function to evaluate the safety, effectiveness and usefulness of the agent as a multi-center study involving 35 institutions in Japan. Out of 510 cases evaluated for the clinical usefulness, valuable information for clinical diagnosis was obtained in 486 cases (95.3%), and 444 cases (87.1%) were judged as "extremely useful" or "useful". Although the positive ratio of abnormalities detected by the agent was as same as that of 99mTc-hexamethylpropyleneamine oxime (99mTc-HM-PAO), the abnormal regions detected by the agent had tendency to be larger in size and to have higher contrast than those detected by 99mTc-HM-PAO. It is concluded that 99mTc-ECD is a safe and useful radiopharmaceutical as a brain perfusion agent for the diagnosis of cerebrovascular diseases and impairment of brain function.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The aim of this study was to detect brain functional deficits in patients with Behçet's disease (BD) and signs or symptoms of central nervous system (CNS) involvement at different times in their clinical history. A total of 24 patients aged 20 to 53years (median age 39years; 20 women, four men) with Behçet's syndrome fulfilling the diagnosis as defined by the syndrome classification were enrolled in this study. Single-photon emission computed tomography (SPECT) with (99m)Technetium (Tc)-hexamethylpropyleneamine oxime (HMPAO) as the perfusion tracer was performed to detect brain lesions. The results of (99m)Tc-HMPAO brain SPECT scans showed impaired perfusion in all cases with neurological complaints (24 out of 24, 100%). Temporal lobes and basal ganglia were the most common areas with such lesions. In contrast, brain MRI and CT images were normal or non-specific in all cases. In conclusion, (99m)Tc-HMPAO brain SPECT imaging is a powerful and sensitive tool for disclosing brain involvement in numerous clinical situations, even including patients with subtle neurological symptoms/signs such as headaches and dizziness. It is also a useful modality for evaluating the effects of treatment and disease monitoring to prevent CNS damage.

Topics: Adult; Behcet Syndrome; Cerebrovascular Disorders; Contrast Media; Female; Humans; Male; Middle Aged; Perfusion Imaging; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Young Adult

Hyperperfusion (HP) is a rare but potentially devastating complication after carotid revascularization. This report describes the clinical efficacy of staged angioplasty (SAP) for carotid artery stenosis to prevent HP after carotid revascularization.. Eighteen of 143 patients with high-grade internal carotid artery stenosis scheduled for angioplasty were considered at high risk of postprocedure HP based on their severely impaired cerebral blood flow (CBF) and cerebral vasoreactivity, which were determined using single-photon emission computed tomography with acetazolamide. Nine of the high-risk patients were treated with carotid artery stenting and the other 9 were treated with SAP, which consisted of balloon angioplasty with undersized balloon catheters (Stage 1) followed by carotid artery stenting 1 to 2 months later (Stage 2).. In the regular carotid artery stenting group, 5 of 9 patients (56%) showed HP phenomenon on single-photon emission computed tomography just after stenting, and 1 patient (11%) developed status epilepticus owing to HP. In the SAP group, none of the 8 patients treated by SAP or the 1 patient who required stent placement during the first stage owing to a wall dissection developed postprocedure HP phenomenon or HP syndrome.. SAP decreased the HP phenomenon on single-photon emission computed tomography after performing these procedures in selected patients. Although additional intervention is needed, SAP is considered a relatively simple and effective method to avoid HP in patients at high risk of HP after carotid revascularization.

Topics: Acetazolamide; Aged; Angioplasty, Balloon; Blood Pressure; Carotid Stenosis; Cerebrovascular Disorders; Diuretics; Female; Humans; Intraoperative Care; Iofetamine; Magnetic Resonance Imaging; Male; Middle Aged; Platelet Aggregation Inhibitors; Postoperative Complications; Radiopharmaceuticals; Stents; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

A case of 49 years old woman with acute, severe suicidal carbofuran poisoning is described. The lowest activity of AChE was 0 IU/L. Because carbamates lead to multiorgan damages, especially affect central nervous system, computer tomography of the brain (CT) and examination of regional cerebral blood flow (99mTc-ECD SPECT) were done. No pathological changes were found in CT. 99mTc-ECD SPECT performed on 14th day of hospitalization, revealed disturbed regional cer- ' ebral flow generally in frontal and occipital lobes. Results of neuropsychological examination were pathological too.

Topics: Carbofuran; Cerebrovascular Disorders; Depression; Female; Humans; Insecticides; Mental Disorders; Middle Aged; Poisoning; Radiopharmaceuticals; Regional Blood Flow; Suicide, Attempted; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Treatment Outcome

Neurological complications have been reported in patients with sickle-cell disease (SCD) using positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT), but not with single photon emission computed tomography (SPECT). The objective of this study was to investigate brain perfusion in the patients with SCD using SPECT after technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO), was administered and compare the findings with those of demography, physical examination, MRI and hematological profile.. The study involved 21 patients (12 males, 9 females, age at study 8-45 years) who were known to be having SCD for a duration of at least 5 years. The patients were not in acute crisis and had normal neurological assessments with no known history of stroke or transient ischemic episode or previous abnormal CT or MRI brain scan, and were right-handed. The brain SPECT was performed after intravenous injection of 740 MBq (20 mCi) 99mTc-HMPAO in adults or an appropriate dose in pediatric patients. The scans were visually interpreted by two nuclear medicine physicians and a decision was reached by consensus. An MRI done 3 months later was interpreted by a radiologist. The demographic data and hematological profile were obtained from the medical records of the patients.. Of the 21 patients, 7 (age 11-22 years) had brain perfusion deficit mostly in the frontal lobe either alone or in combination with temporal and/or parietal lobe. The MRI was abnormal in 2 patients. The brain perfusion deficit was not associated with the demographic data of the patients or hematological profiles.. The findings show that SPECT was useful in detecting brain perfusion deficit in SCD patients, and such an early detection may be clinically useful in the subsequent follow-up of such patients, since it is known that cerebral perfusion deficit can lead to silent infarct and/or overt stroke, and affect cognitive skills.

Topics: Adolescent; Adult; Anemia, Sickle Cell; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Female; Humans; Male; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Four patients with the diagnosis of hysterical hemiparesis and normal magnetic resonance imagings were referred to us for further evaluation. All were being treated with antidepressant or antianxiety drugs or both, with no benefit. In all 4 cases single photon emission computed tomography revealed decreased regional cerebral blood flow in frontal regions in cortical areas corresponding to their neurologic deficits. In all 4 cases improvement followed neurologic treatment. We suspect that reduced blood flow in frontal regions may have produced the neurologic deficits. We call these conditions "pseudohysterical hemiparesis."

Topics: Adult; Aged; Cerebrovascular Disorders; Female; Frontal Lobe; Humans; Hysteria; Magnetic Resonance Imaging; Male; Middle Aged; Paresis; Regional Blood Flow; Technetium Tc 99m Exametazime; Terminology as Topic; Tomography, Emission-Computed, Single-Photon

A voxel based investigation of cerebral blood flow was conducted to identify brain functional differences during resting state between children with developmental language disorder (DLD) and normal controls.. Using DSM-IV criteria, we selected 21 children with DLD. All children were examined by technetium-99m-HMPAO Brain SPECT. Using SPM analyses, we compared the SPECT images of children with DLD and those of 17 control subjects on a voxel by voxel basis using ANCOVA covarying for age.. Reduced cerebral blood flow in the right putamen,the right inferior parietal cortex, and the left globus pallidus were found in children with DLD versus the controls. However, no area of increased cerebral blood flow was observed in children with DLD compared to the controls.. Though results should be interpreted cautiously, this study confirms the presence of functional defects in the basal ganglia and the inferior parietal lobe during the resting state of the brains of children with DLD. It also gives further evidence for functional deficits in basal ganglia as an important factor in the etiology of DLD.

Topics: Age Factors; Brain; Brain Mapping; Cerebrovascular Disorders; Child, Preschool; Female; Humans; Language Development Disorders; Male; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To evaluate the role of MR morphometry in the characterization of cerebral microangiopathy (CMA) in relation to clinical and neuropsychological impairment.. 3D MR images of 27 patients and 27 age-matched controls were morphometrically analysed for regional thickness. The normalized values were related to the patients' clinical and neuropsychological scores. The patients were categorised according to the amount of structural MR signal changes. A ventricle index reflecting internal atrophy was related to MR morphology and cortical thickness as an indicator for external atrophy.. Cortical thickness was significantly reduced in the patients group (3.03 mm +/- 0.26 vs. 3.22 mm +/-0.13 in controls, p=0.001). The severest loss of cortical thickness occurred in severe CMA. Internal and external atrophy evolved in parallel and both showed a significant relationship with structural MR-abnormalities (p<0.05; r=-0.7; r=0.67; r=-0.74, respectively). Neuropsychological performance correlated strongly with the loss of cortical thickness.. Cortical thickness was identified as the most sensitive parameter to characterize CMA. A strong correlation was found of morphometric parameters to the severity of CMA based on a score derived from T2-weighted MRI. The degree of cortical atrophy was directly related to the degree of neuropsychological impairment. Our findings suggest that the cortical thickness is a valid marker in the structural and clinical characterization of CMA.

Topics: Analysis of Variance; Case-Control Studies; Cerebral Cortex; Cerebrovascular Disorders; Cognition Disorders; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Statistics as Topic; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Ultrasonography, Doppler, Color

Topics: Aged; Arterial Occlusive Diseases; Brain Mapping; Carotid Artery, External; Carotid Artery, Internal; Cerebral Angiography; Cerebral Revascularization; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Perfusion; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cerebral hyperperfusion syndrome has been increasingly reported as a complication of carotid angioplasty and stent placement. The aim of the present study was to determine significant predictors of hyperperfusion phenomenon after carotid angioplasty and stent placement.. We retrospectively reviewed 30 consecutive patients with unilateral severe carotid stenosis who underwent angioplasty and stent placement. Resting cerebral blood flow (CBF) and cerebral vasoreactivity (CVR) to acetazolamide challenge were quantitatively measured to evaluate cerebral hemodynamic reserve. Split-dose [(123)I] iodoamphetamine single photon emission CT (SPECT) was performed before and 7 days after carotid angioplasty and stent placement. Technetium-99m hexamethylpropyleneamine oxime (HMPAO) SPECT was performed immediately after the procedure.. Three patients had cerebral hyperperfusion phenomenon immediately after angioplasty and stent placement, as shown by HMPAO SPECT: One developed status epilepticus 2 weeks after the procedure. Significant predictors of hyperperfusion included patient age, pretreatment CVR, and pretreatment asymmetry index ([ipsilateral resting CBF/contralateral resting CBF] x 100). Variables determined not to be significant risk factors included pretreatment resting CBF value, degree of carotid stenosis, and interval from the onset of ischemic symptoms.. Significant predictors of hyperperfusion phenomenon after carotid angioplasty and stent placement included patient age, pretreatment CVR, and pretreatment asymmetry index. Pretreatment CBF measurements, including those obtained by quantifying CVR and performing SPECT immediately after the procedure may aid in identifying patients at risk and in initiating careful monitoring and control of blood pressure to prevent hyperperfusion syndrome.

Topics: Acetazolamide; Aged; Aged, 80 and over; Amphetamines; Angioplasty, Balloon; Carotid Stenosis; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Hemodynamics; Humans; Hyperemia; Iodine Radioisotopes; Male; Middle Aged; Predictive Value of Tests; Radiopharmaceuticals; Retrospective Studies; Stents; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasomotor System

Treatment of childhood leukemia may cause perfusion defects in the brain observed by SPECT. Perfusion MRI is a novel method to study brain perfusion which has not been used previously in this setting. This study was performed to compare SPECT with perfusion MRI in patients with acute lymphoblastic leukemia (ALL) after treatment.. Nineteen children or young adults underwent perfusion MRI at the cessation of treatment (n = 9) or 4-8 years after the treatment (n = 10). Seventeen of them also underwent SPECT at the time of MRI (within 0-3 days, n = 14) or a couple of months later (1.5-6 months, n = 3). SPECT images and relative cerebral blood volume (CBV) and cerebral blood flow (CBF) maps from perfusion MRI were analyzed visually. Relative CBV ratios of gray matter to white matter and thalamus to white matter were also calculated from the perfusion MRI.. Perfusion MRI did not show any focal perfusion defects, while small defects were observed by SPECT in five of 17 children (29%) in the basal, frontal or temporal areas on the left. No significant differences were observed by perfusion MRI in the relative CBV ratios in the different treatment groups. Time since treatment, age at diagnosis, brain irradiation, or findings in conventional MRI or SPECT did not have any effect on the relative perfusion values either.. SPECT may show small perfusion defects after treatment for childhood leukemia which are not visible by perfusion MRI. The clinical significance or prognosis of these defects is not known.

Topics: Adolescent; Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Child, Preschool; Cytarabine; Female; Humans; Iatrogenic Disease; Magnetic Resonance Imaging; Male; Methotrexate; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vincristine

Cocaine abuse has been associated with widely distributed areas of significant cerebral blood flow (CBF) reductions or hypo-perfusion as well as CBF hyper-perfusion, but these perfusion abnormalities have not been examined using newer technologies such as statistical parametric mapping (SPM). These areas of abnormal CBF may be more likely among those who abuse cocaine and alcohol together.. Using SPECT with HMPAO for CBF we compared proportional scaling (PS) to histogram normalization (HEQ) in SPM among 20 controls and 32 recently abstinent cocaine abusers. We then separated the cocaine abusers into two groups (12 cocaine plus alcohol abusers and 20 cocaine alone abusers) and compared both groups to the 20 controls for brain areas of hypo- and hyper-perfusion.. Sensitivity to hypo-perfusion was greater with HEQ than PS. Hypo-perfused areas were more likely in the 12 alcohol plus cocaine abusers than in the 20 cocaine alone abusers or 20 controls, and hyper-perfused areas were significantly more likely among the cocaine abusers than controls. The type of CBF abnormality varied by brain location with hypo-perfusion significantly more likely in occipital and temporal cortex or cerebellum and hyper-perfusion more likely in frontal and parietal cortex.. These abnormalities in brain perfusion are consistent with previous non-SPM approaches that showed more hypo-perfusion in cocaine abusers than controls and appear to reflect vasospasm and potential compensations in cerebral blood flow.

Topics: Adult; Alcoholism; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Cocaine-Related Disorders; Female; Humans; Male; Radiopharmaceuticals; Sampling Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Patients with cardiovascular disease have cognitive function disturbances that are still evident after heart transplantation (HT). The aim of this study was to evaluate cerebral function in transplant patients and to assess whether cyclosporine therapy was responsible for cerebral abnormalities 1 year after transplantation. Six HT patients, eight liver transplant (LT) patients, and ten age-matched healthy controls underwent regional cerebral blood flow (rCBF) assessment by the (99m)Tc-hexamethyl-propylene-amineoxime ((99m)Tc-HM-PAO) single-photon emission computed tomography (SPECT) technique. The rCBF was correlated with cyclosporine blood levels. rCBF in HT and LT patients was similar to that of controls in all regions assayed, except for the frontal inferior region of HT patients, where it was significantly lower than in controls. No correlations between rCBF and cyclosporine blood levels were found in either HT or LT patients. In conclusion, the cerebral abnormalities seen in patients after HT but not after LT may be due to long-standing cerebral hypoperfusion resulting from severe heart disease, whereas cyclosporine does not account for such functional alterations.

Topics: Adult; Cerebrovascular Circulation; Cerebrovascular Disorders; Cognition Disorders; Cyclosporine; Female; Frontal Lobe; Heart Transplantation; Humans; Immunosuppressive Agents; Liver Transplantation; Male; Middle Aged; Postoperative Complications; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Childhood autism is a developmental disability of unknown origin with probable multiple etiologies. The purpose of this study was to compare the changes of regional cerebral blood flow (rCBF) in autistic and non-autistic controls, and to determine the relationship between rCBF on 99mTc-hexamethylpropylene amine oxime (HMPAO) brain SPECT and the scores of the Ritvo-Freeman Real Life Rating Scale (RLRS), IQ levels, and age of autistic children. Eighteen autistic children (four girls, 14 boys; mean age: 6.13 +/- 1.99 years) and 11 non-autistic controls (five girls, six boys, mean age: 6.5 +/- 3.39 years) were examined using 99mTc-HMPAO brain SPECT. All the children satisfying DSM-IV criteria for autistic disorder were taken into evaluation, and scored by the Ritvo-Freeman RLRS. IQ levels of these children were determined by Goodenough IQ test. Six cortical regions of interest (ROIs; frontal (F), parietal (P), frontotemporal (FT), temporal (T), temporo-occipital (TO), and occipital (O)) were obtained on transaxial slices for count data acquisition. The ratio of average counts in each ROI to whole-slice counts for the autistic children was correlated with the scores of Ritvo-Freeman RLRS. Hypoperfusion in rCBF in autistic children compared with the control group were identified in bilateral F, FT, T, and TO regions. We found no relationship between rCBF on 99mTc-HMPAO brain SPECT and the scores of the Ritvo-Freeman RLRS. There was a relationship between bilateral F regions perfusion on 99mTc-HMPAO brain SPECT and the age of autistic children. There was also a negative correlation between IQ levels and the scores of sensory responses, social relationship to people, and sensory-motor responses. Our results suggest that 99mTc-HMPAO brain SPECT is helpful to locate the perfusion abnormalities but no correlation is found between rCBF on 99mTc-HMPAO brain SPECT and the scores of Ritvo-Freeman RLRS.

Topics: Age Factors; Autistic Disorder; Case-Control Studies; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Child, Preschool; Cognition Disorders; Female; Humans; Intelligence; Intelligence Tests; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

MRI shows lacunar infarctions (LI), deep white matter lesions (DWML) and atrophy in cerebral microangiopathy, which is said to lead to vascular dementia. In a first trial series on 57 patients with confirmed pure cerebral microangiopathy (without concomitant macroangiopathy), neuropsychological impairment and (where present) brain atrophy correlated with decreased rCBF and rMRGlu. LI and DWML did not correlate with either neuropsychological impairment or decreased rCBF/rMRGlu. This study was done one year later to detect changes in any of the study parameters.. 26 patients were re-examined for rCBF, rMRGlu, LI, DWML, atrophy and neuropsychological performance (7 cognitive, 3 mnestic, 4 attentiveness tests). Using a special head holder for exact repositioning, rCBF (SPECT) and rMRGlu (PET) were measured and imaged slice by slice. White matter/cortex were quantified using MRI-defined ROIs.. After one year the patients did not show significant decreases in rCBF or rMRGlu either in cortex or in white matter (p > 0.05), nor did any patient show LI, DWML or atrophy changes on MRI. There were no significant neuropsychological decreases (p > 0.05).. Cerebral microangiopathy ought to show progressive neuropsychological, functional (rCBF, rMRGlu) and morphological deterioration over periods > 1 year. It is unlikely that direct cortical damage (e.g., incomplete infarction) is responsible for neuropsychological impairment since one-year follow-up of our patients revealed no progression of brain atrophy or any other cortical damage.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Cognition; Female; Fluorodeoxyglucose F18; Follow-Up Studies; Glucose; Humans; Middle Aged; Neuropsychological Tests; Organ Specificity; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

The objectives of this study were to (1) elucidate the relationship between the mean CBF in the whole brain (Av.mCBF) before rehabilitation of CVD patients and the BI score before and after rehabilitation, (2) determine whether the efficacy of rehabilitation can be predicted by measurement of the Av.mCBF, and (3) investigate what part of the brain was most important to improving the BI score.. The Av.mCBFs in 160 patients with CVD were calculated by Patlak plots with 99mTc-HMPAO before rehabilitation, and we determined the BI score before and after rehabilitation. Based on the BI scores before and after rehabilitation, patients were divided into four groups: Group A, BI = 100; Group B, 80 < or = BI < or = 99; Group C, 60 < or = BI < or = 79; Group D, 0 < or = BI < or = 59. We evaluated the relationship between the Av.mCBF and BI score before and after rehabilitation.. The Av.mCBF before rehabilitation showed a tendency to be more correlated with the BI score after rehabilitation (r = 0.414, p < 0.0001) than before rehabilitation (r = 0.272, p = 0.0006). After rehabilitation, there was a tendency for the Av.mCBF value to increase in direct proportion to the BI score of the group: it was highest in Group A and lowest in Group D. The strongest correlation was found between the frontal lobe regional CBF before rehabilitation and the BI score after rehabilitation (r = 0.343, p < 0.0001).. Measurement of the Av.mCBF before rehabilitation of CVD patients will permit prediction of the efficacy of rehabilitation. Also the regional CBF of the frontal lobe is most important for improving the BI score.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Follow-Up Studies; Humans; Male; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The arterial and venous blood concentration of technetium 99m-labeled hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) reaches an equilibration more rapidly than other CBF tracers. We hypothesized that (99m)Tc radioactivity of a venous sample at equilibrium, which is similar to that of an arterial sample, would allow estimation of the integrated input function for the clinical measurement of CBF by use of single-photon emission CT.. In 53 patients with stable cerebrovascular disease, the radioactivity of a venous sample 5 minutes after injection of (99m)Tc-HMPAO was correlated with 5-minute arterial blood radioactivity and the first 5 minutes of the integrated arterial curves of the lipophilic tracer. The measured CBF values were compared with those of xenon 133.. The radioactivity of 5-minute venous blood was almost equivalent to that of 5-minute arterial blood (r(2) = 0.987; y = 0.993x + 1.63; P : <0.0001). The correlation between the venous blood radioactivity and the integrated arterial lipophilic fraction was excellent (r(2) = 0.935, P : <0.0001). A strong correlation was obtained between (99m)Tc-HMPAO and (133)Xe CBF values (r(2) = 0.825, P : <0.0001). CBF values were reproducible (coefficient of variation, 8.6%).. This approach is fast, simple, and an alternative to continuous blood sampling in clinical quantitative (99m)Tc-HMPAO CBF studies.

Topics: Arteries; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Radiopharmaceuticals; Regional Blood Flow; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed; Veins; Xenon Radioisotopes

Topics: Aged; Brain; Cerebral Amyloid Angiopathy; Cerebral Hemorrhage; Cerebrovascular Disorders; Granuloma; Humans; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasculitis

Various clinical subtypes of patients presenting with sudden-onset ischemic stroke have been recognized, but classification of those types is not simple. We identified various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke with relation to clinical outcomes.. Twelve patients with symptoms of acute ischemic stroke due to middle cerebral artery occlusion underwent perfusion-weighted MR imaging and MR angiography within 6 hours after the onset of symptoms. Perfusion-weighted imaging was performed with a conventional dynamic contrast-enhanced T2*-weighted sequence, and cerebral blood volume (CBV) maps were then created. CBV maps and MR angiographic findings were compared with 99mTc-HMPAO brain SPECT scans, short-term outcomes, and follow-up imaging findings.. The combined CBV and MR angiographic findings were classified into three patterns: arterial occlusion and decreased CBV (n = 8), arterial occlusion and increased CBV (n = 2), and no arterial occlusion and normal CBV (n = 2). These three patterns were strongly related to SPECT findings, short-term outcomes, and follow-up imaging findings. Perfusion on SPECT decreased markedly in the affected regions in all patients with the first pattern, decreased slightly in the second pattern, and was normal in the third pattern. Symptoms were not significantly changed at 24 hours after onset in any of the patients with the first pattern, but resolved completely in all patients with the latter two patterns. Follow-up imaging showed large infarctions in all patients with the first pattern. Initially, no infarction was seen in the second pattern, but watershed infarction developed later in one of these patients.. Hyperacute ischemic stroke may be differentiated into three imaging patterns with different clinical outcomes. The combined use of perfusion-weighted MR imaging and MR angiography may play a substantial role in guiding the choice of treatment of this disease.

Topics: Acute Disease; Aged; Aged, 80 and over; Arterial Occlusive Diseases; Blood Volume; Brain Ischemia; Cerebral Arterial Diseases; Cerebral Infarction; Cerebrovascular Circulation; Cerebrovascular Disorders; Contrast Media; Female; Follow-Up Studies; Humans; Image Enhancement; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Male; Middle Aged; Patient Care Planning; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

This present study was carried out to investigate whether stabilization of Tc-99m-HMPAO with methylene blue (MB) or cobalt chloride (CC) causes a sensible improvement in image quality and how cerebral to noncerebral activity ratios compare with those of Tc-99m-ECD.. 30 minutes after preparation 400-600 MBq unstabilized Tc-99m-HMPAO (N = 35 patients), Tc-99m-HMPAO added with MB (N = 24 patients), added with CC (N = 30 patients) or Tc-99m-ECD (N = 28 patients) were injected. Radiochemical stability was measured in vitro with three chromatographical methods. Image quality was assessed quantitatively using two ratios, one of them determined by count densities of brain/scalp (Os), the other one by count densities of brain/nose (QN). In addition, image quality (0 = bad, 3 = excellent) and background activity (0 = high, 3 = no) were visually assessed by three independent observers.. In contrast to unstabilized Tc-99m-HMPAO the integrity of the complexes of MB-Tc-99m-HMPAO, CC-Tc-99m-HMPAO and Tc-99m-ECD decreased only by a few percent during a period of 2 hours after reconstitution (66.8 +/- 9.9 vs. 93.0 +/- 2.5, 91.8 +/- 1.9 and 96.9 +/- 1.4%, p < 0.001). Qs and Qn (m.v. +/- SD) differed significantly between studies using unstabilized Tc-99m-HMPAO (3.0 +/- 0.4 and 2.1 +/- 0.3), MB-Tc-99m-HMPAO (3.4 +/- 0.4 and 2.3 +/- 0.3), CC-Tc-99m-HMPAO (3.6 +/- 0.6 and 2.6 +/- 0.4) and those using Tc-99m-ECD (4.3 +/- 0.7 and 4.8 +/- 1.4, p < 0.05 and < 0.001). Stabilization with CC or MB resulted in significant higher scoring of image quality and lower scoring of background activity in comparison to that of unstabilized Tc-99m-HMPAO, without reaching the scores obtained with Tc-99m-ECD.. It is concluded that stabilization of Tc-99m-HMPAO with MB or CC definitely improves image quality in rCBF-SPECT, without reaching that of Tc-99m-ECD. Improvement of image quality results from the reduction of the amount of decomposition products that contribute to considerable extracerebral activity.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebrovascular Disorders; Cobalt; Cysteine; Depression; Drug Stability; Female; Humans; Male; Methylene Blue; Middle Aged; Neurodegenerative Diseases; Organotechnetium Compounds; Radiopharmaceuticals; Scalp; Sensitivity and Specificity; Sleep Apnea Syndromes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

This study examined the relationship between magnetic resonance diffusion imaging and autoradiographic markers of cerebral blood flow (99mTc-hexamethylpropylene amine oxime) and cerebral hypoxia (125I-iodoazomycin arabinoside) in a rat model of stroke. Middle cerebral artery occlusion in the rat was performed using an intraluminal suture approach. Diffusion, hypoxia, and blood flow maps were acquired 2 hr following occlusion, and were compared with T2 images and histology at 7 hr. Two hours following middle cerebral artery occlusion the lesion distributions from the diffusion maps and hypoxic autoradiographs were similar. The blood flow threshold for increased uptake of the hypoxic marker was approximately 34 +/- 7% of the normal flow. The combination of diffusion or hypoxic images with perfusion maps allowed differentiation between four regions: 1) normal tissue; 2) a region of decreased perfusion but normal diffusion and normal uptake of hypoxic marker; 3) a region of decreased perfusion, decreased diffusion and increased uptake of hypoxic marker; 4) a region of decreased perfusion, decreased diffusion and low uptake of hypoxic marker. The areas for increased uptake of hypoxic marker and decreased diffusion are equivalent, indicating similar blood flow thresholds. Regions of oligaemic misery perfusion, ischaemic misery perfusion and lesion core may be delineated with the combination of diffusion or hypoxic images and perfusion maps.

Topics: Animals; Autoradiography; Cell Hypoxia; Cerebrovascular Circulation; Cerebrovascular Disorders; Diffusion; Disease Models, Animal; Magnetic Resonance Imaging; Male; Nitroimidazoles; Rats; Rats, Wistar; Technetium Tc 99m Exametazime

A 72-year-old right-handed woman developed aphasia after a left supplementary motor area (SMA) infarct. She had a right hemiparesis, more paretic on the leg, a tendency to look to her left, and loss of spontaneity. Neuropsychological deficits were mainly in the initiation of language production. She did not speak spontaneously, but responded and articulated well to questions. She named objects correctly when presented, and could repeat words, phrases, and sentences well. She had a difficulty in reading aloud, writing spontaneously and writing to dictation, but preserved the ability to copy written material. This is another rare case of SMA aphasia.

Topics: Aged; Aphasia, Broca; Cerebrovascular Disorders; Female; Humans; Magnetic Resonance Imaging; Motor Cortex; Neuropsychological Tests; Occipital Lobe; Parietal Lobe; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Since the perioperative mortality of coronary artery bypass surgery is high in patients with cerebrovascular disease, it is crucial to assess a cerebrovascular risk before operation. Acetazolamide (ACZ) was applied to brain SPECT to evaluate the vascular reserve, and ACZ stress brain imaging was useful for predicting perioperative cerebrovascular events. We performed 201Tl myocardial and 99mTc-hexamethyl-propyleneamine oxime (HMPAO) brain SPECT with ACZ stress simultaneously to a patient with severe coronary artery disease and experienced the abnormality of 201Tl myocardial imaging with ACZ, as did that with dipyridamole. Technetium-99m-HMPAO brain SPECT showed no defect. Brain SPECT with ACZ demonstrated the region of poor coronary vascular reserve, which suggested myocardial ischemia induced by ACZ in a patient with severe coronary artery disease.

Topics: Acetazolamide; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Coronary Artery Bypass; Coronary Circulation; Coronary Disease; Female; Heart; Humans; Myocardial Ischemia; Preoperative Care; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon; Vasodilator Agents

Because 99mTc-HMPAO and 99mTc-ECD are both used for SPECT imaging of cerebral blood flow, the question arises whether there are any differences in their respective regional cerebral distribution. For that purpose, visual and semiquantitative comparisons between 99mTc-HMPAO and 99mTc-ECD studies were performed.. Seventeen patients (4 women; 13 men; age 45-89 yr; mean age 71 yr) with various neurological diseases, except acute/subacute stroke, were investigated twice with 99mTc-HMPAO and 99mTc-ECD using a triple-headed rotating SPECT camera. After image reorientation, the two studies were evaluated visually. Seventy regions of interest (ROIs) were drawn manually and the same set of ROIs was applied in both studies. Regional indices (RI) normalized to individual brain values were calculated and first compared between two random patient groups. Second, for all patients, RI for 70 and later for 27 regions (gained after summing values of corresponding regions in different brain slices) were compared by using a paired Student's t-test applying Bonferroni's correction.. Visual evaluation demonstrated relatively high 99mTc-ECD uptake in occipital and comparatively low uptake in mediotemporal regions. Calculation of RI revealed significantly higher values in the right cerebellum, brainstem, mediotemporal regions, right basal ganglia and the thalamus in the 99mTc-HMPAO SPECT studies and higher values in the occipital, supratemporal/inferior parietal and parietal cortex in the 99mTc-ECD SPECT studies, respectively.. Significant differences in regional tracer distribution between 99mTc-HMPAO and 99mTc-ECD could be detected, probably caused by different tracer kinetics. The results indicate that direct comparisons of studies performed with 99mTc-HMPAO and 99mTc-ECD are not possible and the use of either tracer can be favorable in different clinical questions.

Topics: Aged; Aged, 80 and over; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Cysteine; Epilepsy; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Quantitative studies of cerebral blood flow (CBF) combined with a vasodilatory challenge have defined a subgroup of patients with symptomatic carotid occlusion who have an increased risk for stroke. These are patients whose CBF paradoxically decreases in response to a vasodilatory challenge. Recent reports suggest that qualitative CBF techniques, such as single photon emission tomography with 99m-hexamethylpropyleneamine oxime, can also define the same high-risk subgroup. To determine whether qualitative measures of CBF are sufficient for predicting the risk of stroke, we converted our quantitative CBF data, obtained with xenon-enhanced computed tomography (Xe/CT), to qualitative ratios in a manner similar to that used with single photon emission tomography data.. We analyzed CBF values within the territory of the middle cerebral artery for 94 patients with symptomatic carotid occlusion. Values obtained using Xe/CT before and after the intravenous administration of 1 g of acetazolamide were used to derive an asymmetry index: (Coccl - Cnon)/Cavg x 100. The difference between the postacetazolamide asymmetry index and the baseline asymmetry index was used to classify the patients into groups according to CBF values. The threshold for abnormal qualitative CBF reactivity was defined as a percent change in the asymmetry index of less than -10%. Quantitative (Xe/CT) CBF was considered abnormal ("steal" response) when the response to acetazolamide (percent change) on the occluded side was a decrease of 5% or greater.. Of 34 patients whose cerebrovascular reserves were considered compromised based on qualitative criteria, 17 (50%) did not have a steal response as defined by quantitative Xe/CT CBF (i.e., false positive). Eleven of 62 (18%) who were not considered compromised by qualitative criteria had a steal response (i.e., false negative). Our data indicate that a qualitative approach has a 61% sensitivity and a 75% specificity for detecting patients with compromised reserves. Further, the positive predictive value of this method is only 50%. Therefore, the two methodologies do not predict the same patients as having compromised reserves.. Previous studies have shown that patients at high risk for stroke can be identified with quantitative CBF methods. This study shows that the important subgroup cannot be accurately defined with qualitative methodology. The implications of using the more reliable methodology are important for individual patient management and for designing clinical trials.

Topics: Acetazolamide; Carotid Stenosis; Cerebrovascular Circulation; Cerebrovascular Disorders; Collateral Circulation; False Negative Reactions; False Positive Reactions; Humans; Risk; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Vasodilation; Xenon

Topics: Adult; Aged; Brain; Cerebrovascular Disorders; Child, Preschool; Cysteine; Dementia; Epilepsy; Humans; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Twenty-two patients with systemic lupus erythematosus and 13 healthy controls were included in a cerebral blood flow study and underwent brain-dedicated single-photon emission computed tomography using 99m technetium-d, l-hexamethylpropylene amine oxime together with a brain computed tomography scan. Plasma levels of antiphospholipid antibodies (lupus anticoagulant and anticardiolipin IgM and IgG antibodies) were also determined. Brain computed tomography showed signs of focal cerebral ischemia in 4 patients (18%), whereas cerebral blood flow by single-photon emission computed tomography was abnormal in 13 of 22 patients (59%), who showed bilateral or monolateral hypoperfusion in the temporo-parietal regions. Patients with abnormal cerebral blood flow had a longer duration of disease than those with normal blood flow (8.9 +/- 1.9 years vs. 5.3 +/- 1.5 years, P < 0.05). Plasma antiphospholipid antibodies were present in 15 patients (68%), but the prevalence was similar in those with normal (6/9, 66%), or abnormal (9/13, 69%) cerebral blood flow. No statistically significant difference in lupus anticoagulant or anticardiolipin antibodies was observed between patients with and without cerebral blood flow abnormalities. Our study shows that patients with systemic lupus erythematosus frequently have cerebral blood flow abnormalities, which could precede those observed by computed tomography. Plasma lupus anticoagulant and anticardiolipin titers were not correlated with normal cerebral blood flow.

Topics: Adolescent; Adult; Antibodies, Anticardiolipin; Autoimmune Diseases; Brain Ischemia; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Middle Aged; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Vasculitis

The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (99mTc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using 99mTc-HMPAO SPET is reliable in clinical evaluations.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brain Concussion; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Consciousness Disorders; Humans; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Discrepancies have been reported between the findings of Tc-99m HMPAO and Tc-99m ECD brain perfusion SPECT imaging. This study investigated the discrepancies in the accumulation of these tracers using dynamic SPECT to detect the super early phase of distribution. Thirteen patients with luxury perfusion or high flow states were studied with both dynamic and standard SPECT using Tc-99m HMPAO and Tc-99m ECD within 1-3 days. Standard SPECT showed discrepancies in 6 of 13 patients. Patients with meningioma and cerebral thrombosis had increased accumulation of Tc-99m HMPAO and decreased uptake of Tc-99m ECD. Patients with arteriovenous malformation, subarachnoid hemorrhage, and cavernous angioma had decreased accumulation of both tracers, but to different degrees. Dynamic SPECT showed increased or normal accumulation (i.e., essentially no discrepancy) in the first few minutes. However, Tc-99m HMPAO had a longer retention time than Tc-99m ECD in the ensuing 5-10 minutes. Dynamic SPECT revealed a similar accumulation pattern but different washout rates for the two tracers. Tc-99m HMPAO might be a more suitable tracer to detect high flow states or luxury perfusion because the findings on standard SPECT were more in agreement with those of dynamic SPECT using this tracer.

Topics: Adult; Aged; Brain; Brain Diseases; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Cysteine; Female; Humans; Hyperemia; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Adult; Antiphospholipid Syndrome; Brain; Cerebral Angiography; Cerebral Infarction; Cerebrovascular Disorders; Female; Humans; Lupus Erythematosus, Systemic; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Vasculitis

Prospective and retrospective language evaluations and single photon emission computed tomography (SPECT) scans were performed in order to study the relationship between post-stroke recovery from aphasia and changes in cerebral blood flow (CBF) in groups of patients who had made a good recovery and those who had not. For the prospective study, 20 right-handed patients with aphasia secondary to an acute cerebrovascular accident (CVA) in the left middle cerebral artery territory received language evaluations with a Japanese Standard Language Test of Aphasia (SLTA), and SPECT scans performed twice, at a mean of 3.2 and a mean of 9.2 months post-onset. Only one slice of SPECT data was analysed. A significant correlation was observed between the severity of the initial language deficit and initial CBF on the left side, but not the right. Initial CBF was not a predictor for future language recovery in either hemisphere. There was a correlation between the change in the left mean hemispheric CBF (but not the right) and the change in the overall SLTA severity rating from 3 to 9 months post-stroke. In the retrospective study, 16 right-handed patients with residual aphasia secondary to CVA in the left middle cerebral artery territory received SLTA and SPECT at a mean of 82.8 months post-onset. The patients had also received initial language evaluation with SLTA at a mean of 6.5 months post-onset. In contrast to the prospective study, the results demonstrated that the mean left hemispheric CBF at approximately 7 years post-onset did not differ between good and poor recovery groups. However, the mean right hemispheric CBF of the good recovery group was higher than that of the poor recovery group in the frontal and the thalamic regions, and also in the left frontal region. The results of these complementary studies suggest that the initial language recovery within the first year post-onset may be linked primarily to functional recovery in the dominant hemisphere, where an increase in CBF was observed at 9 months post-onset. The increased perfusion adjacent to the lesion may be crucial for early recovery in aphasia. Subsequent language recovery and the long-term recovery in aphasia may be related to slow and gradual compensatory functions in the contralateral hemisphere, specifically in the homotopic frontal and thalamic areas.

Topics: Adult; Aged; Aphasia; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Follow-Up Studies; Humans; Japan; Language; Language Tests; Male; Middle Aged; Prospective Studies; Radiopharmaceuticals; Regional Blood Flow; Retrospective Studies; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

The rationale behind thrombolytic therapy in acute ischemic stroke is penumbral salvage by rapid restoration of cerebral blood flow. The relationship, however, between early reperfusion (potentially composed of both nutritional and nonnutritional components) and outcome remains unclear.. To establish the relationship between reperfusion parameters and outcome variables (Canadian Neurological Scale, Barthel Index, outcome CT scans), we used 99Tc-hexamethylpropyleneamine oxime (99Tc-HMPAO) single-photon emission CT (SPECT) to examine 41 acute ischemic stroke patients. All patients had at least 2 SPECT studies (24 with 3 studies), and none had been treated with thrombolytic or other acute investigational drugs.. A total of 106 studies were performed. Mean time to acute study was 9.2 hours; that for subacute study was 42 hours and for outcome study was 150 days. Hypoperfusion (HP) volumes at each of the 3 time points correlated with outcome clinical state and final infarct size. Both early reperfusion (61% of patients) and nutritional reperfusion alone (56%), which is early reperfusion maintained at outcome, were associated with improvement in clinical state and better functional outcome. Early HP volume change (acute minus subacute HP volume) and total HP volume change (acute minus outcome HP volume) also correlated with clinical improvement and better outcome.. This study establishes the benefit of spontaneous reperfusion after ischemic stroke and emphasizes the prognostic value of HP deficit volumes. 99Tc-HMPAO SPECT may be used to screen patients and group them according to perfusion deficit in acute stroke trials, thereby decreasing patient numbers required to show drug effect.

Topics: Adult; Aged; Aged, 80 and over; Brain Ischemia; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Nutritional Physiological Phenomena; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Neurosarcoidosis with recurrent stroke-like episodes has been reported only rarely in the literature. We repeatedly measured brain magnetic resonance images (MRI), SPECT, and electroencephalograms (EEG) in a 32-year-old male patient with this condition. In the acute stage of the episodes, he showed semi-coma followed by severe dysphasia; left-frontal EEG delta wave activities and left-sided hyperperfusion SPECT were noted. Gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) MRI findings were aggravated diffusely in the convalescent stage of the disease rather than in the acute stage. The EEG and SPECT findings were clearly reflective of an early stage of acute encephalomeningitis caused by the neurosarcoidosis, and thus are more useful than MRI for evaluation of the acute inflammatory process in this condition.

Topics: Adult; Biopsy; Brain Diseases; Cerebrovascular Disorders; Electroencephalography; Humans; Magnetic Resonance Imaging; Male; Radiopharmaceuticals; Recurrence; Sarcoidosis; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Ninety-five patients with syndrome X were studied by brain single-photon emission computed tomographic examination; 72 (76%) had pathologic findings suggestive of cerebral perfusion abnormalities. These findings support the hypothesis of a vascular disorder not confined to cardiac vessels.

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Microvascular Angina; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The pathophysiology of neuropsychological disorders due to right deep-seated hemispheric lesions remains a debated point. We undertook this study to check the hypothesis according to which remote cortical dysfunction could be responsible for the occurrence of neglect. Twenty-eight patients presenting with a right-sided subcortical stroke were studied. A neuropsychological battery of tests suitable for assessment of possible visuo-spatial neglect was performed as well as HMPAO SPECT. Neglect was observed in 15 cases out of 28. The lesion's site (at CT and/or MRI) did not allow discrimination between patients without neglect and patients with neglect. The latter however could be distinguished from the former by the presence of a remote decrease in cortical blood flow in the right temporo-parietal region. By suggesting that cortical involvement is necessary for the occurrence of neglect, the results were interpreted according to a network approach in which subcortical neglect is attributed to a cortical deprivation from afferent input in the posterior part of the brain.

Topics: Aged; Aged, 80 and over; Attention; Brain Mapping; Cerebral Cortex; Cerebrovascular Disorders; Dominance, Cerebral; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Psychomotor Performance; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The aim of our work was to study the state of regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in patients with different degree of carotid stenosis after CE. Thirty six patients with carotid stenosis aged 46-65 years (mean age 55 years) were studied. In all the patients before and one month after carotid endarterectomy (CE) single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO, Ceretec, Amersham) and SPECT with labelled in vivo 99mTc-red blood cells (99mTc-RBC) were carried out. According to the results of scintigraphic studies the regional cerebral blood flow (rCBF, ml/min/100g), the volume of hypoperfusion (Vhypoperf., sm3), the stroke volume (SV, sm3), the interhemispheric ratio of rCBF (IRrCBF) and the regional cerebral blood volume (rCBV, ml/100g) were calculated. CE leads to the bilateral increase of cerebral perfusion especially at the side of more expressed damage putting away interhemisphere asymmetry of rCBF. After CE the regression of SV and Vhypoperf were revealed. In asymptomatic disease patients with monolateral stenosis of carotid arteries rCBF reaches normal values and regions of hypoperfusion are not revealed. Surgical recanalization of carotid arteries causes expressed changes of scintigraphic parameters of rCBV: normalization of initially increased values of rCBV in patients with asymptomatic development of stenosed atherosclerosis of carotid arteries and subsequent increase of rCBV in comparison with preoperative level in patients who underwent acute stroke with neurological deficit and patients with poor clinical signs and multiple damage of both internal carotid arteries.

Topics: Acute Disease; Aged; Arteriosclerosis; Blood Volume; Brain; Brain Ischemia; Carotid Artery, Internal; Carotid Stenosis; Cerebrovascular Circulation; Cerebrovascular Disorders; Endarterectomy, Carotid; Erythrocytes; Female; Follow-Up Studies; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radiopharmaceuticals; Stroke Volume; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

In 65 type I diabetic patients we prospectively evaluated brain perfusion by means of single-photon emission tomography after the injection of 740- 1110 MBq of technetium-99m hexamethylpropylene amine oxime. Thirty-five of the patients presented complications secondary to their diabetes. None showed CNS symptoms. A semiquantitative analysis was performed drawing 50 symmetrical regions of interest (ROIs) per patient. The relative contribution of each ROI to the total blood flow in each slice was compared with the relative contribution of the same ROI in a control group of ten healthy volunteers. Relative values of any ROI in the study group higher or lower than the mean +/-2 SD in respect of the same ROI in the control group were considered abnormal. The results revealed hypoperfusion in 207 ROIs in the 65 patients with diabetes mellitus: of these ROIs, 113 were frontal, 10 frontotemporal, 20 temporal, 18 parietal, 11 occipital and 35 cerebellar. A total of 137 ROIs showed hyperperfusion: 17 frontal, 3 frontotemporal, 19 temporal, 18 parietal, 19 parieto-occipital, 29 occipital and 32 cerebellar. Out of 65 type I diabetic patients, 61 showed at least one hypoperfused ROI (P = 0.0064 vs. controls) and 25 showed more than three hypoperfused ROIs. None of the control subjects showed more than three hypoperfused regions (P<0.001). The results obtained demonstrate the existence of subclinical abnormalities of brain blood perfusion in patients with type I diabetes mellitus and no history of cerebrovascular disease, thereby allowing the initiation of intensive preventive measures.

Topics: Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Diabetes Mellitus, Type 1; Humans; Prospective Studies; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The purpose of this study was to analyse the frequency of the different pathological perfusion patterns in SPECT in a clinical, unselected population of patients with Alzheimer's disease. In 91 patients and 16 control subjects regional cerebral blood flow (rCBF) was measured with Single Photon Emission Computed Tomography (SPECT) using 99mTc-hexa-methyl-propyleneamine oxime (HMPAO). 95% confidence intervals obtained from the perfusion values of the control subjects were used to define normal perfusion ranges. The frequency of perfusion deficits in the left frontal, temporal, parietal and occipital lobes were 62.2%, 60.4%. 70.3% and 23.1%, respectively. In the right hemisphere the corresponding values were 60.4%, 58.2%, 63.7% and 9.9%. With the exception of the occipital lobes these frequencies were not significantly different. The analysis of the perfusion pattern of each patient revealed 35 different combinations of lobes with perfusion deficits. The temporo-parietal perfusion deficits were not more frequent than the temporofrontal perfusion deficits. These results suggest that in the clinical routine a high variety of heterogeneous rCBF patterns have to be expected.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Case-Control Studies; Cerebrovascular Disorders; Cognition Disorders; Female; Follow-Up Studies; Humans; Male; Middle Aged; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Four methods of brain edge detection on brain SPET perfusion (99Tcm-hexamethylpropylene amine oxime) images were compared: ellipse adaptation, simple thresholding (four threshold values), a low threshold (40%) followed by 1, 2 or 3 pixel erosion, and the Deriche 3D adaptive cut-off frequency method (four filter widths: alpha = 1, 2, 3 or 4). The SPET data of six patients were reconstructed to obtain 10 axial slices, each 10 mm thick, covering the whole brain. On the 60 axial slices, the methods were compared based on automaticity, computation time and accuracy of edge detection compared with morphological edges drawn manually on the patients' 3D co-registered magnetic resonance imaging (MRI) scans. The proportion of pixels inside the contour defined by the MRI scan but outside the SPET edge (p(i)), and the proportion of pixels inside the contour defined by the SPET image but outside the MRI contour (pe), were calculated. The thresholding methods provided interesting results, particularly the application of a low threshold value (40%), followed by a 2 pixel erosion, which required a computation time of 12 s (p(i) = 5.7 +/- 2.2%; pe = 2.7 +/- 0.9%). Because of adjustments to each slice of the ellipse axis, the processing time of this method was about 3 min (p(i) = 1.5 +/- 1.4%; pe = 11.3 +/- 3.4%). The Deriche 3D filter was time-consuming (6 min for 10 slices on a NXT workstation, SMV International). With this method, the best edge fitting was found with a filter width of 3 and 4 (p(i) = 9.6 +/- 11.1%; pe = 14.1 +/- 23.2%; alpha = 3). Three-dimensional filtering methods must be refined to reduce the computation time and to improve brain edge fitting accuracy when compared with the eroded thresholding method.

Topics: Brain; Cerebrovascular Disorders; Gamma Cameras; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Middle Aged; Radiopharmaceuticals; Reproducibility of Results; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

SPECT-HM-PAO allows to detect the regional cerebral blood flow and total diminution of the brain perfusion still before morphological substrate evolution in CT scan, without invasive technologies. SEARCH GOAL: The authors have analyzed data obtained by SPECT-99mTc HM-PAO in the group of 46 patients suffering from cerebrovascular disorders and they have compared them with results aimed by CT scans. Both, the SPECT-99mTc HM-PAO and CT scan were performed within 48 hours or later after the onset of the stroke; some of CT scans were repeatedly performed.. They discovered 40 positive and 6 negative SPECT-HM-PAO findings, 26 positive and 20 negative CT scans. SPECT investigation more frequently discovers circulatory failures in the clinically altered hemisphere than the CT scan does in a substrate; SPECT discloses hypoperfusion of the clinically unaltered hemisphere if silent hypoperfusion is present. The ipsilateral foci of CT substrates were significantly less frequently observed (p < 0.001) than some ipsilateral regional hypoperfusions. Not only the number, but also size and extent of hypoperfusional foci searched by SPECT are significantly higher and wider than the numbers and dimensions of substrates observed by CT (p < 0.001).. CT scan diagnostic possibilities are restricted by the time factor (CT examinations performed within 48 hours since the onset of the stroke are significantly less frequently positive than those performed later-p < 0.001). SPECT examination has not such a limiting time factor (p > 0.05). MEANING: Hence SPECT-HM-PAO renders early, long lasting and wide information on the restriction of the overall and regional perfusion, independently of the fact as to whether the reduction of cerebral perfusion is, or is not going to result in ischemic necrosis and/or ischemic sclerosis. SPECT renders correlation of the perfusion disorder earlier, wider in space, and more frequently than the CT scan, and therefore it is a prerequisite to the disclosure of the mentioned silent focal blood flow reductions. (Graph 12, Fig. 3, Ref. 4.)

Topics: Adult; Aged; Aged, 80 and over; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Topics: Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Follow-Up Studies; Humans; Male; MELAS Syndrome; Organotechnetium Compounds; Oximes; Radiography; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

To evaluate stroke risk assessment of balloon test occlusion of the internal carotid artery (ICA) with enlarged haemodynamic monitoring prior to permanent ICA occlusion.. 24 patients with cervical metastasis (n = 18), cavernous meningiomas (n = 3) or inoperable cavernous aneurysms (n = 3) were examined. The test occlusion was monitored by EEG, neurological examinations and transcranial Doppler sonography of the ipsilateral middle cerebral artery with evaluation of the cerebrovascular reserve capacity. Additionally 99mTc-HMPAO-SPECT imaging was added showing the perfusion during test occlusion.. In one (4%) patient the test occlusion had to be interrupted previously due to an acute neurological deficit. This patient and two (8%) patients with highly pathological test results in SPECT and TCD were excluded from permanent carotid occlusion. In 6 (25%) patients quantitative TCD monitoring could improve the stroke risk assessment by differentiating the patients in a low and high risk group. 6 (25%) patients were definitely occluded without haemodynamic complications, but two patients suffered from embolic infarctions which cannot be predicted by this procedure.. The multimodal balloon test occlusion with enlarged haemodynamic monitoring allows haemodynamic stroke risk assessment prior to permanent occlusion of the ICA.

Topics: Adult; Aged; Aged, 80 and over; Brain; Carotid Artery Diseases; Carotid Artery, Internal; Catheterization; Cerebral Infarction; Cerebrovascular Disorders; Contrast Media; Embolization, Therapeutic; Female; Head and Neck Neoplasms; Hemodynamics; Humans; Intracranial Aneurysm; Intracranial Embolism and Thrombosis; Male; Meningeal Neoplasms; Meningioma; Middle Aged; Neurologic Examination; Organotechnetium Compounds; Oximes; Prognosis; Regional Blood Flow; Risk Factors; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Luxury perfusion is a well-known phenomenon that can mask ischaemic lesions in patients with cerebral infarction, thus making diagnosis difficult. In this study, we evaluated the incidence of luxury perfusion over a 3-week period following a stroke episode. The usefulness of crossed cerebellar diaschisis (CCD) as a complementary feature in the diagnosis of cerebral infarction was also evaluated using 99Tcm-hexamethylpropyleneamine oxime (99TcmHMPAO) brain single photon emission tomography (SPET). Twelve patients diagnosed as having a hemispheric ischaemic stroke of the middle cerebral arterial territory were enrolled in the study. Each patient underwent a total of four 99Tcm-HMPAO brain SPET examinations, 1 day, 1 week, 2 weeks and 3 weeks following the stroke episode. Our results show that the incidence of luxury perfusion was 67% (8/12) after 1 week, 75% (9/12) after 2 weeks and 83% (10/12) after 3 weeks. The incidence of CCD was 33% (4/12) after 1 day, 50% (6/12) after 1 week, 42% (5/12) after 2 weeks and 33% (4/12) after 3 weeks. We conclude that the detection of cerebral infarction is difficult 2 weeks or more after a stroke episode. The interval between the stroke episode and examination must be considered when reading the 99Tcm-HMPAO image. In addition, CCD may be helpful for the diagnosis of cerebral infarction within the first week after a stroke episode, especially in cases of an unidentified ischaemic region on the 99Tcm-HMPAO hemispheric image. However, the value of CCD is limited 2 weeks or more following the stroke episode.

Topics: Aged; Brain; Cerebellum; Cerebral Arteries; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Follow-Up Studies; Functional Laterality; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed

Single-photon emission computed tomography (SPECT) with 99mtechnetium-hexamethylpropylamineoxime (HMPAO) noninvasively shows brain perfusion in patients after acute stroke. However, the clinical significance of the increased HMPAO uptake remains unclear. In this study, consecutive patients with hemispheric hemorrhagic and ischemic stroke admitted to the hospital were evaluated prospectively. The increased uptake of HMPAO was determined by visual analysis of SPECT images. The pathogenic mechanism of ischemic stroke was determined using the clinical and computed tomography (CT) criteria including the Toronto Embolic Scale. Of the 500 consecutive patients with acute hemispheric stroke, SPECT was performed in 458 at a mean time 5 +/- 7 days after the onset of symptoms. A strong association was found between SPECT perfusion patterns and pathogenic subtypes of stroke (p < 0.0001). Thus, in 95% of patients with intracerebral hemorrhage the focal absence of perfusion was found, and 26% of lacunar infarctions presented with a normal SPECT appearance. The mean volume of lacunar lesions that did not produce significant abnormalities on SPECT was 2.5 +/- 1.2 ml. Increased HMPAO uptake was associated with a cardioembolic mechanism of stroke: High and mixed perfusion patterns were present subacutely in 29% of patients with cardioembolic stroke, compared to 15% of patients with other types of ischemic stroke (p < or = 0.0006). The increased uptake of HMPAO on SPECT as determined by visual analysis is associated with a cardioembolic mechanism of cerebral ischemia, which could be explained by glutathione-mediated trapping of the tracer during reperfusion and later in newly developed granulation tissue. HMPAO-SPECT may help in early management decisions since it indicates stroke pathogenesis and evolution.

Topics: Acute Disease; Aged; Brain; Brain Ischemia; Cerebral Hemorrhage; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Glutathione; Granulation Tissue; Humans; Intracranial Embolism and Thrombosis; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prospective Studies; Reperfusion; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Topics: Cerebral Infarction; Cerebrovascular Disorders; Follow-Up Studies; Humans; Hyperemia; Intracranial Embolism and Thrombosis; Organotechnetium Compounds; Oximes; Plasminogen Activators; Reperfusion; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Tissue Plasminogen Activator; Tomography, Emission-Computed, Single-Photon

The aim of this study was to validate a simplified semiquantitative method of evaluating a single-day stress cerebral perfusion test to obtain cerebrovascular reserve capacity (CVRC) for routine clinical uses. A split-dose protocol was tested in 36 pairs of technetium-99m hexamethylpropylene amino oxime baseline (low dose) and acetazolamide (high dose) stress brain single-photon emission tomographic (SPET) studies from 16 patients with cerebrovascular disease. The images were displayed on a semiquantitative color scale with (corrected) and without (uncorrected) image subtraction, dose adjustment, and decay correction. The representative CVRC was determined by placing 3x3 pixel regions of interest on midthalamic and midcerebellar slices. The corrected and uncorrected relative changes in CVRC were correlated using linear regression. The relative changes of corrected (x) and uncorrected (y) CVRC by quantitative analysis were highly correlated in a linear fashion (y=0.67x+0.002, r=0.998, P<0.0005). As predicted by theory, the slope was related to the ratio of split dose and independent of ROI sampling. Single-day split-dose stress brain SPET can be accurately performed without image subtraction and complicated dose adjustment or decay correction for clinical studies.

Topics: Acetazolamide; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Organotechnetium Compounds; Oximes; Subtraction Technique; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Single-photon emission computed tomography (SPECT) is used in patients with acute stroke but as yet is of controversial value. We investigated an association of brain perfusion changes in stroke patients with stroke severity, volume of brain damage, and recovery.. Consecutive patients with hemispheric stroke were studied prospectively with serial neurological examinations using the Canadian Neurological Scale (CNS), CT. and 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT. Visual SPECT patterns of brain perfusion (normal, high, mixed, low, and absent) were correlated with the severity of stroke, lesion volume, and short-term outcome.. SPECT studies were performed in a total of 458 consecutive acute stroke patients within 2 weeks after the onset (mean time, 5 days; range, 1 to 12 days). SPECT perfusion patterns correlated with stroke severity (CNS score) during the first 2 weeks (P < .001). Focal absence of brain perfusion on SPECT was associated with the largest volume of brain damage: 104 +/- 84 mL (P < .0001). SPECT perfusion patterns predicted the shortterm outcome: 97% of patients with normal and increased HMPAO uptake made good recovery, 52% of those with decreased perfusion had moderate stroke, and 62% of patients with absent patterns fared badly. In a multiple logistic regression model, admission CNS scores had the strongest predictive value (P = .0001). SPECT had its own prognostic value independent of clinical judgment (P = .03). SPECT statistically improved predictive power of the CNS score (+1% receiver operating characteristic curve area, [X2]2 = 20, P < .001) because of distinction between focal decrease or absence of brain perfusion in patients studied within the first 72 hours of stroke.. Visual brain perfusion patterns correlate with the extent, severity, and short-term outcome of hemispheric stroke. HMPAO SPECT may improve the prognostic value of clinical examination if performed during the first 72 hours of stroke.

Topics: Acute Disease; Aged; Aged, 80 and over; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Neurologic Examination; Organotechnetium Compounds; Oximes; Prognosis; Prospective Studies; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; Visual Perception

We assessed cerebral blood flow in 78 diabetic patients (40 Type 1 and 38 Type 2) with no previous history of central nervous system disease using 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) single photon emission tomography (SPET) and found areas of severe hypoperfusion in 36% of them. All cerebral anatomical regions showed abnormalities related to hypoperfusion, but they were most frequently seen in the fronto-temporal region, followed by the occipital and parietal regions. 99Tcm-HMPAO SPET has been shown to be able to detect subclinical alterations in blood flow in diabetes, a finding that may account for the high prevalence of cerebrovascular disease seen in these patients. This technique could, therefore, play an important role in future preventative strategies.

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Diabetes Complications; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Neuropathies; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Past analysis of dysbaric-induced cerebral perfusion defects, demonstrated by 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) single photon emission tomography in divers using quantitative and/or univariate techniques, has resulted i considerable controversy regarding the significance of these lesions compared to those seen in control subjects, correlations with clinical findings and the role of 99Tcm-HMPAO as a prognostic indicator in decompression sickness. We tried to address these problems by using a multivariate approach to a voxel-by-voxel analysis, involving the use of principal components, to determine ranges of normality in 50 reference controls. In subsequent images, abnormality was defined as 10 spatially connected voxels at an appropriate significance level of three standard deviations. The images of 50 divers with clinically diagnosed 'bends' were compared with those of a further 40 normal population controls with no previous history of loss of consciousness, head injury or dysbarism. The results showed that 19 of 50 divers with 'bends' and 3 of 40 population controls had significant perfusion defects, representing a significant difference between divers with dysbarism and population controls at the level P < 0.002. It is concluded that dysbarism causes significant cerebral cortical perfusion defects in affected divers both in 'silent' and symptomatic (clinically correlated) areas.

Topics: Adolescent; Adult; Case-Control Studies; Cerebrovascular Circulation; Cerebrovascular Disorders; Decompression Sickness; Diving; Humans; Image Processing, Computer-Assisted; Male; Multivariate Analysis; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

This study, performed in 94 consecutive patients referred for evaluation, demonstrates the clinical utility of cerebral SPECT imaging. In a significant percentage of patients (47%), the additional information provided by SPECT resulted in an alteration in clinical management. Long-term follow-up will be necessary to determine the effect of these management decisions on patient outcome.

Topics: Brain; Brain Diseases; Case-Control Studies; Cerebrovascular Disorders; Craniocerebral Trauma; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A contour detection algorithm for cerebral studies, using the method of Tomitani, has been implemented on a single-photon emission tomographic (SPET) system. It is based on the detetion by threshold of the brain edge in the sinogram and does not depend on the reconstruction algorithm. Thirteen normal subjects underwent an examination on both computed tomography (CT) and SPET using a head holder to ensure the reproducibility of the positioning. The CT scan contour of the brain was drawn manually according to the brain parenchyma limits. The SPET brain contour was obtained by use of the Tomitani algorithm after the threshold had been determined on an active cylindrical phantom. Using a threshold of 37% of the maximum uptake, the length of the contour as well as the area obtained with SPET and CT were not found to be statistically different. The method of Tomitani, which is simpler and faster then previous methods, provides contours which superimpose very well with CT scan images. Application to patients with unilateral pathological defects is possible by requiring that the contour is symmetrical.

Topics: Adolescent; Adult; Aged; Algorithms; Brain; Case-Control Studies; Cerebrovascular Disorders; Child; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Organotechnetium Compounds; Oximes; Reproducibility of Results; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

The effects of two post-acquisition corrections on the visual and quantitative analysis of technetium-99m hexamethylpropylene amine oxime (HMPAO) single-photon emission tomography (SPET) were determined. The corrections were for: (1) the improper spatial orientation of the patient data sets, and (2) the non-linear uptake of HMPAO across the blood-brain barrier. Reorienting the SPET image data sets removed observers' uncertainty in assessment caused by suspected head tilt; however, it increased their uncertainty due to perceived subtle perfusion deficits. Applying the correction to compensate for the decrease in uptake of HMPAO in high-flow regions resulted in an increase in the number of positive assessments. In a study involving 30 patient studies, intra-observer reliability increased from 62% to 83% (average of two observers) after applying both of the corrections, while inter-observer reliability improved from 62% to 81%. Quantitative methods of analysing the images are also affected by the corrections. In an ROI-based classification scheme, the quantitative assessments of more than one-half of the images are affected by the two corrections. These results need to be considered when comparing both quantitative and visual results from different studies in which the corrections may or may not have been applied.

Topics: Algorithms; Cerebellum; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Image Processing, Computer-Assisted; Observer Variation; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Percutaneous transluminal angioplasty (PCTA) is increasingly used to treat extracerebral arterial stenosis. The present study evaluates the safety and efficacy of PCTA treatment of symptomatic intracranial atherosclerotic stenosis.. A series of 22 vessels in 17 patients were treated with PCTA. All patients had recurrent neurological symptoms referable to the stenotic vessel despite optimal medical therapy. Critical (> 70%) arterial stenosis was confirmed by angiogram, and angioplasty was performed with a 3.0- to 3.5-mm Stealth balloon.. The average preangioplasty stenosis (North American Symptomatic Carotid Endarterectomy Trial criteria) was 72 +/- 8% (mean +/- SD), with a significant improvement seen after angioplasty; the best angiographic stenosis (after healing of intimal injury, if any) was 43 +/- 24% (P < .001). Overall PCTA was successful in 82% of the vessels. There were two strokes during angioplasty for a 30-day morbidity rate of 9.1% per treated vessel and 11.7% per case. The other 15 patients were clinically evaluated at 3 and 6 months; all cases were without further events. Restenosis was evaluated in 8 patients (12 vessels) with an angiogram at 6 months showing further improvement compared with the initial post-PCTA stenosis (51 +/- 10% versus 37 +/- 21% [P = .05]).. PCTA may be a beneficial therapy in selected cases of symptomatic intracranial atherosclerotic stenosis. Further study using a randomized trial is needed.

Topics: Aged; Angioplasty, Balloon; Arteriosclerosis; Cerebral Angiography; Cerebrovascular Disorders; Constriction, Pathologic; Female; Follow-Up Studies; Humans; Intracranial Arteriosclerosis; Intraoperative Complications; Male; Middle Aged; Neurologic Examination; Organotechnetium Compounds; Oximes; Recurrence; Safety; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tunica Intima

We compared regional cerebral blood flow (CBF) of CBF-SPECT brain imaging in two brain perfusion agents, N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) and 99mTc-hexamethylpropyleneamineoxime (99mTc-HMPAO), in the same patients with ischemic cerebrovascular disease. In eight healthy volunteers and 16 patients with chronic stage of cerebral infarction, single photon emission computed tomography (SPECT) data was normalized to the count density of the tracer in the whole brain, and then converted to the absolute units of CBF by multiplying average 133Xe-CBF in the whole-brain. One-way analysis of variance (ANOVA), grouped by the affected and contra lateral hemispheres of patients and right and left hemispheres of normal volunteers, was used to assess the changes in pattern of regional CBF (rCBF) among disease and control groups. Regional CBF was significantly reduced in patients compared with normal controls in all the brain regions on both tracers: F = 6.6-14 and p = 9.1 x 10(-4) - 1.6 x 10(-6) in IMP, and F = 5.8-14.8 and p = 2 x 10(-3) - 8.2 x 10(-7) in HMPAO. F value was higher in IMP than that of HMPAO in five of nine brain regions of interests (the frontal, temporal and occipital cortices, thalamus and the striatum), whereas F value was higher in HMPAO than IMP in the other four regions (the central lobule, parietal cortex, hippocampus and the centrum semiovale).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Amphetamines; Analysis of Variance; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Iodine Radioisotopes; Iofetamine; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single-photon emission computed tomography (SPECT) and transcranial Doppler sonography (TCD) may help to determine a target group of patients with maximum therapeutic response for tissue rescue after acute stroke. As previously described, the cerebral perfusion index represents a combination of these techniques, and is calculated by multiplying assigned values for TCD and SPECT perfusion patterns. The three grades of cerebral perfusion index (1-5, 6-12, 15-20) may predict short-term outcome if the index is based on SPECT and TCD performed within the first 6 hours after stroke. A total of 30 consecutive patients were studied (18 with middle cerebral artery stroke and 12 with transient ischemic attack or minor stroke). Neurological deficit was scored using the Canadian Neurological Scale. SPECT and TCD were performed 4 +/- 2 hours after the onset. Forty-five minutes were required to perform both tests, evaluate the results, and calculate the cerebral perfusion index. The mean score (+/- standard deviation) of the neurological deficit on admission was 84 +/- 20 in patients with transient ischemic attack/minor stroke and 54 +/- 33 in patients with stroke (p < 0.009). The volume of ischemic lesion was measured on computed tomography scans performed more than 3 days after the ictus. Patients with transient ischemic attack/minor stroke had lesion volumes of 8 +/- 7 cm3 compared to 72 +/- 26 cm3 for those with stroke (p < 0.0001). The mean cerebral perfusion index in the transient ischemic attack group was 18 +/- 4, while in the stroke group it was 4 +/- 1 (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acute Disease; Aged; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; Cerebrovascular Disorders; Echoencephalography; Female; Humans; Ischemic Attack, Transient; Male; Neurologic Examination; Organotechnetium Compounds; Oximes; Prospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ultrasonography, Doppler, Transcranial

The prognostic value of single-photon emission computed tomography (SPECT) remains controversial. The aim of this study was to compare the prognostic value of stroke severity, stroke subtypes, and SPECT indices and to determine which predictive factors have an independent effect on clinical outcome.. We studied 55 consecutive patients with acute (< 12 hours) carotid infarct within 36 hours of symptom onset with SPECT. Clinical presentation was assessed by the Canadian Neurological Scale and stroke subtypes. SPECT indices were the degree and size of hypoperfusion and crossed cerebellar diaschisis as assessed by a semiquantitative analysis. Outcome was evaluated by the functional status and mortality (Rankin Scale score at 1 month).. The Rankin Scale score correlated with the degree (r = .580; P < .00001) and size (r = .616; P < .00001) of hypoperfusion. The mean degree and size of hypoperfusion were significantly higher in patients with poor outcome. Crossed cerebellar diaschisis had no significant predictive value. Statistical analysis determined threshold values for the Canadian Neurological Scale score and the degree and size of hypoperfusion for the functional status and mortality. The degree and size of hypoperfusion had no higher performance than the Canadian Neurological Scale score. The negative predictive value was excellent for both clinical and SPECT indices. Multivariate analysis selected only the size of hypoperfusion as an independent predictor for the functional status (P = .004) and the Canadian Neurological Scale score for mortality (P = .009).. SPECT performed within 36 hours of onset predicts clinical outcome, but different clinical and SPECT indices with threshold values should be chosen according to the relevant outcome end point.

Topics: Aged; Aged, 80 and over; Carotid Artery Diseases; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Predictive Value of Tests; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To investigate the discrepancy between 99mTc-hexamethylpropyleneamine oxime (HMPAO) and 133Xe rCBF SPECT, the findings of thirty patients with reasonable rCBF reduction on 133Xe SPECT were compared with HMPAO SPECT and X-ray CT. The subjects did not include the cases of acute and subacute CVD. Both SPECT were performed within two weeks by ring-type dynamic SPECT (HEADTOME, Simadzu, Japan). In comparison between the SPECT findings by 133Xe and 99mTc-HMPAO, the subjects were classified into three groups as follow. Group A: Similar findings in the both SPECT were noted in 6 cases (20%). Group B: Smaller findings on HMPAO SPECT than that by 133Xe were in 11 cases (37%). Group C: No findings of rCBF reduction on HMPAO SPECT were in 13 cases (43%). The rCBF of the lesion measured by 133Xe SPECT in the group C was 24-35 ml/100 g/min. The density of HMPAO in the lesion did not correlate with the rCBF value. Only the severity of CT findings tend to correlate with the density of HMPAO. These results suggest that the reduction of HMPAO density depends directly on some kind of neural injury rather than the rCBF value. The injury may be caused by the flow reduction under the threshold of each neural cell. So the correlation between HMPAO density and actual rCBF might show like sigmoid curve. Then the HMPAO SPECT might directly reflect the regional extraction and fixation ratio, and the reduction of blood flow cause the minute neural-injury in the lesion of moderately reduced rCBF.

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Xenon Radioisotopes

Cortical remote effects of right deep-seated lesions were studied with two cerebral blood flow measurement methods (two-dimensional xenon-133 inhalation and 99mTc HMPAO SPECT) in a population of 13 right-handed stroke patients. A neuropsychological battery of tests suitable for assessment of possible visual neglect was performed. Neglect was present in 7 cases. A regional cortical hypoperfusion was observed in all patients. However, in neglect patients it was more extended and involved the right inferior parietal region suggesting a causal relationship between cortical dysfunction and neuropsychological deficit. This finding supports the model attributing neglect to a unilateral attention-arousal defect in a cortico-limbic-reticular loop.

Topics: Aged; Aged, 80 and over; Arousal; Attention; Brain Damage, Chronic; Brain Mapping; Cerebral Cortex; Cerebrovascular Disorders; Dominance, Cerebral; Female; Humans; Limbic System; Male; Middle Aged; Neural Pathways; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Psychomotor Performance; Regional Blood Flow; Reticular Formation; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon Radioisotopes

In this study, three semi-automated (SA) methods for brain single photon emission computed tomography (SPECT) analysis were evaluated and compared with a quantitative manual (QM) method that allowed precise demarcation of telencephalic and cerebellar regions of interest.. Twenty patients with traumatic brain injury or stroke were imaged by SPECT after injection of 30 mCi (1110 MBq) of Tc-99m HMPAO: The SA methods included: 1) SA left-to-right ratio method, which generated uptake ratios in 4 pairs of symmetric brain sectors in each slice; 2) adjusted scale method, which displayed each slice according to a linear 10-color scale; and 3) SA brain-to-cerebellum ratio method, which exhibited a color scale indicating 5% change in the ratio.. The concordance with QM method was 85% for the adjusted scale method and 80% for the SA left-to-right ratio method. A combination of the Adjusted Scale Method and SA left-to-right ratio method yielded concordant results with the QM method in 95% of patients. Brain-to-cerebellum ratio method gave inconsistent findings because of variable cerebellar activity.. Semi-automated methods reliably evaluated relative brain perfusion in most patients. Whereas the adjusted scale method had the best correlation with the QM method, a combination of the adjusted scale method and SA left-to-right ratio method ws the most useful for routine analysis of brain perfusion. Semi-automated brain-to-cerebellum ratio method was found to be the least useful because of variability of cerebellum uptake, particularly when the brain uptake was higher than the cerebellum. The QM method allowed precise and most accurate delineation of regions of interest for quantitation of relative brain perfusion but required considerable operator input and knowledge of brain anatomy.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brain; Brain Injuries; Cerebellum; Cerebral Cortex; Cerebrovascular Circulation; Cerebrovascular Disorders; Data Display; Female; Humans; Image Enhancement; Male; Middle Aged; Organotechnetium Compounds; Oximes; Reproducibility of Results; Technetium; Technetium Tc 99m Exametazime; Telencephalon; Tomography, Emission-Computed, Single-Photon

Fifteen patients who had bilateral mediofrontal hypoactivity and 30 control subjects without this SPECT anomaly underwent Tc-99m HMPAO brain SPECT imaging. Bilateral mediofrontal hypoactivity was found in various neurologic disorders, including subcortical arteriosclerotic encephalopathy, lacunar state, chronic alcoholism, progressive nonvascular dementia, carbon monoxide poisoning, and diabetes mellitus. This SPECT abnormality was, however, specifically associated with three clinical signs: motor disabilities predominating in the lower limbs, urinary incontinence, and akinetic mutism.

Topics: Akinetic Mutism; Alcoholism; Cerebrovascular Circulation; Cerebrovascular Disorders; Dementia; Female; Frontal Lobe; Humans; Male; Middle Aged; Motor Skills; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Urinary Incontinence

The aim of this retrospective study was to assess the contribution of thallium-201 single-photon emission tomography (SPET) in the detection and differential diagnosis of brain tumours. In 90 patients 201Tl SPET was performed because of clinical or radiological suspicion of tumoral invasion, completed by technetium-99m hexamethylpropylene amine oxime and 99mTc-sestamibi SPET in some patients. For all tumours, diagnosis was based on biopsy or autopsy. Other diagnoses were made only after clinical and radiological follow-up for at least 6 months. Histologically tumours consisted of astrocytoma stage I or II (number of patients, n = 6), astrocytoma stage III (n = 8), glioblastoma multiforme (n = 14) and oligodendroglioma (n = 3), brain metastasis (n = 14), lymphoma (n = 3), meningioma (n = 3), pituitary adenoma (n = 2), pineal tumour (n = 1), colloid cyst (n = 1) and craniopharyngioma (n = 1). False-negative studies included pineal tumour (n = 1), colloid cyst (n = 1), craniopharyngioma (n = 1), astrocytomas stage I or II (n = 6) and stage III (n = 3), oligodendroglioma (n = 2) and metastasis in the brain stem (n = 1). Additional metastases approximately < 1.5 cm were not detected in two patients and 201Tl SPET underestimated tumoral extent in one patient suffering from glioblastoma multiforme (n = 1). A false-positive study was obtained in a patient with skull metastasis (n = 1). All 15 patients who were finally shown to suffer from ischaemic infarction had a normal SPET study 9-28 days after the onset of symptomatology. Of five patients with haemorrhagic infarction, studied within 2 weeks, four were false-positive. Of six patients with intracranial haemorrhage, studied 9-39 days later, one showed focal 201Tl accumulation. Two further false-positive studies consisted of angioma and epidural haematoma. Finally, SPET studies were normal in six patients with definite diagnosis of (reactive) gliosis (n = 3), Binswanger's encephalopathy (n = 1), postinfectious encephalopathy (n = 1) and multiple sclerosis (n = 1). In the patient population presented, sensitivity of 201Tl SPET for supratentorial brain tumours was 71.7% and specificity was 80.9%. Clinical information and control SPET studies in combination with early, 30-min and 3- to 4-h delayed imaging may be expected to improve on these figures. On the other hand it seems that, in addition to tumoral histology, the presence of tumours in the fossa posterior and small volumes contribute to the occurrence of fals

Topics: Adult; Aged; Aged, 80 and over; Brain Neoplasms; Cerebrovascular Disorders; Child; Diagnosis, Differential; False Negative Reactions; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Retrospective Studies; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

The authors present a case of basilar artery migraine in a 33-year-old woman who was initially misdiagnosed as having a cerebrovascular or mental disorder and subjected to MRI and cerebral angiography, which, however, did not show any pathologic findings. During admission to the university hospital, she lost consciousness. An emergency Tc-99m HMPAO brain SPECT showed a significant decrease of regional cerebral blood flow in the right temporal and occipital cortices, and right cerebellar hemisphere, where regional cerebral blood flow was decreased by 10-24% as compared to the left side. The second brain SPECT during a symptom-free phase showed the reversion of regional cerebral blood flow to normal in these areas. Basilar artery migraine was diagnosed by the finding of reversible ischemia in the territory of the right basilar artery on brain SPECT images and the clinical picture.

Topics: Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Diagnostic Errors; Female; Humans; Mental Disorders; Migraine Disorders; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vertebrobasilar Insufficiency

We reported a case of subacute stroke which showed high uptake of 99mTc-d,l-hexamethylpropyleneamine oxime (HMPAO) in the reperfused infarct corresponding to slightly decreased perfusion by 133Xe inhalation CBF measurement. In the chronic stage, both SPECT images of 99mTc-HMPAO and 133Xe showed low perfusion in the affected lesion. It was, therefore, considered that the high uptake of 99mTc-HMPAO had represented luxury perfusion. In the subacute stage of stroke, high uptake of 99mTc-HMPAO may imply luxury perfusion but not always hyperperfusion. It is suggested that the fractional fixation of 99mTc-HMPAO temporarily change in the affected lesion and it is essential to take into consideration the clinical stage for the interpretation of SPECT images.

Topics: Acute Disease; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Male; Organotechnetium Compounds; Oximes; Reperfusion; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Sneddon syndrome is defined as a clinical entity consisting of livedo racemosa generalisata (LRG) and cerebrovascular lesions, which often lead to physical and mental handicaps. Four patients with LRG and the suspected diagnosis of Sneddon syndrome had HMPAO-SPECT studies. The patients underwent CT and/or MR brain imaging and three patients had Duplex sonography of the cerebral arteries (TCD). Brain SPECT was abnormal in all patients, whereas CT/MRI revealed a cerebral lesion in only one patient and all TCD studies were normal. HMPAO-SPECT is valuable in detecting disturbed regional cerebral blood flow before irreversible ischemic insults occur, thus allowing the diagnosis of Sneddon syndrome at an early stage.

Topics: Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Diagnostic Imaging; Female; Humans; Organotechnetium Compounds; Oximes; Skin Diseases, Vascular; Syndrome; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To report the development and validation of a technique of dual tracer single-photon emission CT brain imaging using technetium-99m hexamethylpropyleneamine oxime and iodine-123 iodoamphetamine agents and the application of this technique in patients with a variety of diagnoses.. Contamination between the two isotopes' energy windows was calculated by opening both energy windows while scanning a group of patients using a single isotope. To compare uniformity of I-123 down-scatter, Tc-99m studies were performed both before and after the administration of I-123 in five of 24 dual studies. The 24 patients studied with the dual-isotope technique were evaluated during acetazolamide testing, trial balloon occlusion, or embolization of an arteriovenous malformation.. In a dual acquisition, average count contamination of an I-123 study by Tc-99m was less than 1% of the total I-123 counts, and contamination of a Tc-99m study by I-123 was approximately 12% of the total Tc-99m counts. Tc-99m studies performed both before and after the administration of I-123 demonstrated that contaminating counts do not adversely affect scan interpretation. Dual-tracer scans were completed in all 24 patients, 10 of whom showed changes after intervention.. Dual-tracer single-photon emission CT brain scans of adequate diagnostic quality are possible using Tc-99m and I-123.

Topics: Acetazolamide; Adolescent; Adult; Aged; Amphetamines; Brain; Brain Diseases; Cerebrovascular Disorders; Female; Humans; Iodine Radioisotopes; Male; Middle Aged; Models, Structural; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Despite the clinical and pathologic indicators implicating injury to the basal ganglia in children with hyperkinetic movement disorders, we were previously unable to identify lesions in these structures by means of cranial computed tomography or magnetic resonance imaging. We evaluated regional cerebral perfusion measured by single photon emission computed tomography (SPECT) with technetium 99m hexamethyl propylene amine oxime as a technique to localize functional cerebral abnormalities in eleven children who had a movement disorder after hypothermic cardiac surgery. Perfusion defects of the deep gray matter were noted in six of these eleven patients and cortical perfusion defects in nine. For both cortical and subcortical defects a strong right-sided predilection was present. Our findings suggest functional brain injury not detectable by conventional cranial computed tomography and magnetic resonance imaging in these patients. We speculate that these perfusion defects might relate to the behavioral and developmental sequelae in survivors of this syndrome. SPECT may identify subclinical injury in patients at risk for future neurodevelopmental problems and contribute to our understanding of the mechanisms of cerebral injury in the patient operated on for cardiac disease.

Topics: Brain; Cardiac Surgical Procedures; Cerebrovascular Disorders; Child; Child, Preschool; Female; Humans; Infant; Magnetic Resonance Imaging; Male; Movement Disorders; Organotechnetium Compounds; Oximes; Postoperative Complications; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Organotechnetium Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

This report describes a comparative study between technetium-99m ethyl cysteinate dimer (ECD) and 99mTc-hexamethylpropylene amine oxime (HMPAO) in five neurological patients. The conversion kinetics of the tracers in the blood from forms capable of diffusion across the blood-brain barrier to non-diffusible forms were studied by arterial sampling and rapid octanol extraction. We observed that HMPAO has a faster conversion rate in the blood but that the fraction of the injected dose available for brain extraction is higher than in the case of ECD. Regional brain concentrations of the tracers were measured with single-photon emission tomography (SPET) 35 min and 60 min after the injection and remained stable within this interval. On the basis of the measurements of the arterial input and of SPET brain concentrations of the tracers, the regional steady-state influx constants (Ki in ml/min/g) were determined for several brain regions. In the grey matter the Ki values were (mean +/- SD) 0.32 +/- 0.03 and 0.35 +/- 0.04 for HMPAO and ECD, respectively; in the white matter the values were 0.23 +/- 0.01 and 0.23 +/- 0.02, respectively. The Ki values of the two tracers in corresponding regions were closely correlated (P < 0.001). The correspondence of the Ki values of ECD and HMPAO demonstrates that ECD can also be considered a tracer that may be used for quantitative measurements of brain perfusion.

Topics: Aged; Alzheimer Disease; Cerebrovascular Disorders; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We attempted to make a linearization correction for the acetazolamide 99mTc-HMPAO SPECT image. These results were compared to those by PET using the H2(15)O-bolus injection method. The subjects consisted of eleven patients with cerebrovascular diseases. The SPECT images were obtained by the double injection method in the resting state and after an administration of acetazolamide (1 g). Linearization correction was performed according to the Lassen's method. In this study, three different methods were compared, namely fixed Fr and alpha (70 ml/min/100 ml and 1.08), individual determination of Fr and alpha based on PET data, and finally the normalization of the two scan for administered dose, fixed Fr and alpha (50 ml/min/100 ml and 1.5). The corrected count rate ratios of the 99mTc-HMPAO SPECT images were correlated well with the values of regional cerebral blood flow measured by PET in all methods. Therefore, the first method was considered to be a simple and reliable one. In the last method, the relative change of cerebral blood flow after the administration of acetazolamide was calculated. The means of the percentage increase of cerebral blood flow were in good accord between 99mTc-HMPAO SPECT and PET. However, they showed much discrepancy when individually compared.

Topics: Acetazolamide; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Image Interpretation, Computer-Assisted; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

In the management of major cerebral artery obstruction, cerebral perfusion reserve is key to introducing cerebral revascularization surgery. The purpose of this study was to evaluate the feasibility of assessing cerebral perfusion reserve by consecutive 99mTc-hexamethyl-propyleneamine oxime (99mTc-HMPAO) SPECT with 5% carbon dioxide (CO2) inhalation.. The CO2 inhalation and consecutive 99mTc-HMPAO SPECT study was performed on 30 chronic ischemic cerebrovascular disease patients with unilateral major cerebral artery obstruction and on 27 patients without. CO2 reactivity was expressed as the percent increase of 99mTc-HMPAO accumulation from the baseline (%Change) and as a constant k' that was the ratio of 99mTc-HMPAO accumulation per 1 mmHg change of end-tidal CO2 tension by exponential curve fitting.. The mean %Change and k' in the middle cerebral artery (MCA) territory on the side without an obstructive lesion or in the cerebellum ranged from 10.0% to 11.1% and from 0.98% to 1.13% per mmHg, respectively. In the MCA territory, an obstructive lesion was noted in 5.9% versus 0.54% per mmHg in the contralateral MCA territory (p < 0.01). Eleven of 30 patients with major cerebral artery obstruction revealed significant asymmetry in the k' value between bilateral MCA territories.. The results showed compromised cerebral perfusion reserve in the obstructed major cerebral artery territory. The present method was proven clinically useful for evaluating cerebral perfusion reserve in patients with unilateral major cerebral artery obstruction.

Topics: Adult; Aged; Arterial Occlusive Diseases; Blood Pressure; Carbon Dioxide; Cerebrovascular Circulation; Cerebrovascular Disorders; Chronic Disease; Female; Heart Rate; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A normal atlas for HMPAO rCBF SPECT images was obtained from images of 53 normal controls. Following image registration and normalization, a mean image was extracted, while images representing correlated normal deviants were identified using principal component analysis. These images formed the "building blocks" of the atlas. For subsequent images, the atlas was used to create a "nearest normal equivalent" image, which was compared to a residual standard deviation image to determine the significance of deviations in the new image.. Images from 30 patients (10 with Alzheimer's disease; 12 with single or multiple infarcts; and 8 normals) were analyzed.. Using an optimal decision level, 10/10 patients with Alzheimer's disease and 11/12 patients with infarcts were correctly identified, with only one false-positive resulting. We utilized a database of images obtained from normal controls to create a normal atlas.

Topics: Alzheimer Disease; Brain; Cerebral Infarction; Cerebrovascular Disorders; Humans; Methods; Organotechnetium Compounds; Oximes; Reference Values; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Seventeen of 19 patients (67 +/- 8 yr, 17 males and 2 females) had more than 75% unilateral stenosis or occlusion of the internal carotid or middle cerebral artery and two patients had carotid endarterectomy that previously had 90% stenosis of the internal carotid artery. They were studied during upright 99mTc-HMPAO brain SPECT. HMPA was injected immediately after arising from a supine position. Patients were classified into Group A (n = 10) with occlusion of the internal carotid or the middle cerebral artery or Group B (n = 9) with more than 75% unilateral stenosis of the internal carotid or the middle cerebral artery and with carotid endarterectomy. Additional cerebral blood flow perfusion abnormalities between upright and supine 99mTc-HMPAO brain SPECT were detected in seven patients in Group A and in only one patient in Group B. Semiquantitative analysis showed that the asymmetric ratios between upright and supine positions changed significantly in Group A from 0.82 +/- 0.15 to 0.89 +/- 0.10 (p < 0.01), but not in Group B, from 0.89 +/- 0.11 to 0.92 +/- 0.12 (ns). Additional perfusion abnormalities were relevant to occlusion of the internal carotid or middle cerebral artery indicated postural cerebral hypoperfusion. We conclude that upright 99mTc-HMPAO brain SPECT visualizes postural cerebral hypoperfusion possibly related to silent cerebral ischemia.

Topics: Aged; Brain; Carotid Artery Diseases; Carotid Artery, Internal; Cerebrovascular Circulation; Cerebrovascular Disorders; Constriction, Pathologic; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Posture; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Cerebrovascular Disorders; Diving; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The value of acute cerebral blood flow measurements in stroke prognosis is controversial. No previous study has determined whether acute perfusion deficits independently add to a validated clinical prognostic score. We aimed to compare the value of acute hypoperfusion deficits with a quantitative clinical score in stroke prognosis and to correlate the changes in perfusion with brain recovery.. Volumetric analysis of regional hypoperfusion was performed in 38 patients with middle cerebral infarction within 72 hours of onset by use of single photon emission computed tomography and 99mTc hexamethylpropylene amine oxime. Stroke severity was assessed by the Canadian Neurological Score and Barthel Index. Allen's prognostic score was determined acutely in all patients. Clinical outcome was evaluated in 36 of 38 patients, of whom 18 had repeat blood flow studies.. Acute hypoperfusion correlated with both the outcome Barthel Index (P < .001, r = -.61) and Canadian Neurological Score (P < .001, r = -.64). Allen's score correlated better with both the outcome Barthel Index (P < .001, r = .80) and Canadian Neurological Score (P < .001, r = .81). Acute hypoperfusion deficits, after allowing for Allen's score, independently predicted neurological but not functional outcome. Despite overall neurological improvement, mean hypoperfusion increased on the repeat blood flow studies (P < .05).. Volumetric analysis of acute regional hypoperfusion within 72 hours of onset predicts stroke outcome after 3 months, but Allen's score is a better prognostic method. Neurological recovery is not associated with chronic infarct reperfusion.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebral Arterial Diseases; Cerebral Infarction; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prognosis; Regional Blood Flow; Regression Analysis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Twenty patients with strokes were studied to evaluate volume and surface three-dimensional (3D) displays in Tc-99m HMPAO brain SPECT imaging using a triple-head gamma camera interfaced with a 64-bit super computer. In each patient, after an intravenous injection of 20 to 30 mCi of Tc-99m HMPAO, a first-pass cerebral flow study and brain SPECT images at 30 to 60 minutes were obtained. Although the cerebral lesion was more clearly delineated with surface 3D and volume 3D, crossed cerebellar diaschisis in seven patients was more clearly exhibited by volume 3D rather than surface 3D imaging. Volume and surface 3D displays enhance continuity of structures and understanding of spatial relationships; these displays view the brain from all angles, and thus the location and extension of lesion(s) in the brain are much easier to appreciate. It is concluded that 1) both surface and volume 3D displays equally enhance SPECT interpretation; and 2) volume 3D display enhances demonstration of crossed cerebellar diaschisis, but surface 3D display does not.

Topics: Brain; Cerebrovascular Disorders; Gamma Cameras; Humans; Image Processing, Computer-Assisted; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Glasgow Coma Scale; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cerebral infarction is the result of cerebrovascular insufficiency and itself creates complex changes in cerebral hemodynamics. To allow recognition of patterns of change in regional cerebral blood flow (r-CBF) caused by cerebral infarction, the authors present an atlas of Tc-99m hexamethylpropyleneamine oxime (Tc-99m HMPAO) SPECT brain scan sections for a variety of strokes demonstrating typical vascular territorial involvements and evolution of morphologic and r-CBF change. Sections from MRI or CT are shown with SPECT images of the stroke lesion for comparison of the complementary information provided by regional cerebroperfusion and by morphology. Examples of SPECT during acute, subacute, and chronic stages of stroke are provided. To illustrate the temporal evolution of stroke and accompanying changes in the "stroke penumbra," case examples of acute tissue necrosis, luxury perfusion, ischemia, and diaschisis are presented. Methods for semiquantitative analysis of morphologic versus r-CBF defect size after acute stroke are described. How brain SPECT scans conducted during Diamox initiated cerebrovascular stress tests can complement the information obtained from baseline studies and assist in the interpretation of r-CBF abnormalities is also demonstrated.

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Magnetic Resonance Imaging; Male; Medical Illustration; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

A noninvasive simple method for quantitative radionuclide angiography with 99mTc-dl-hexamethyl propylene amine oxime (99mTc-HMPAO). The method of graphical analysis was employed for the evaluation of the unidirectional influx constant (Ku) from the blood to the brain for the tracer. The Ku values were standardized to represent objective and comparable values, brain perfusion indices (BPI), among studied subjects by setting the ratio of ROIbrain size to ROIaorta size to 10. The mean +/- SD of the whole-brain BPI values for the 41 normal controls was 11.15 +/- 2.61, and biphasic reduction with advancing age was observed. The mean of the whole-brain BPI of 7.95 with SD of 2.35 in 103 patients with cerebrovascular disorders was significantly lower than that in normal controls. The right to left ratio of BPI showed wider dynamic range than that of the total counts of SPECT. This technique is quite easy to apply as an adjunct to SPECT and may be helpful in the quantitative evaluation of brain perfusion in routine clinical studies.

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Angiography; Technetium Tc 99m Exametazime

Topics: Brain; Brain Ischemia; Cerebrovascular Disorders; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime

99mTc-HM-PAO cerebral SPECT and whole body scintigraphy (WBS) were performed in 5 patients without cerebro-vascular disease (CVD) (Group 1), 31 patients with CVD but not hemiparesis (Group 2) and 18 patients with CVD and hemiparesis (Group 3). Four ROIs were drawn manually around the whole body (WB), brain (Br), right and left thigh (Th). We calculated some ratios: the total counts in the brain over the total counts in the whole body (Br/WB), the total counts in the thigh over the total counts in the whole body (Th/WB) and the mean counts in the thigh over the mean counts in the brain (Th/Br). The Br/WB was 6.9 +/- 1.8%, rt-Th/WB was 4.9 +/- 2.1%, lt-Th/WB was 5.1 +/- 1.3% and Th/Br was 0.46 +/- 0.17 in group 1. Whole body scintigraphies in group 1 revealed clear and similar images between right and left thigh. The Br/WB was 6.7 +/- 1.4%, Th/WB of paretic side was 4.6 +/- 1.0%, Th/WB of non-paretic side was 5.8 +/- 1.2% and Th/Br was 0.47 +/- 0.18 in group 3. The Th/WB in non paretic side was significantly higher than that in paretic side (p < 0.01). The thigh images in group 3 revealed clearly different between paretic and non-paretic thigh. In conclusion we could acquire the clear thigh images with 99mTc-HM-PAO. It was possible that we evaluated not only cerebral perfusion but also muscle atrophy and/or perfusion in patients with CVD using 99mTC-HM-PAO.

Topics: Adult; Aged; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Thigh; Tomography, Emission-Computed, Single-Photon

Brain perfusion SPECT imaging using Tc-99m ethyl cysteinate dimer (ECD) was carried out in 12 patients with chronic cerebrovascular disease. The sensitivity of lesion detection and lesion-to-normal tissue contrast was compared with those of I-123 IMP and Tc-99m HMPAO. Eight patients underwent all three studies and the remaining four patients had Tc-99m ECD and I-123 IMP scans. The sensitivity of lesion detection and lesion contrast was analyzed quantitatively using an asymmetric index determined by the equation: 100 x [right - left[/(right + left). In the cerebral cortex, cerebellum, and white matter, I-123 IMP showed higher lesion sensitivity than Tc-99m ECD and Tc-99m HMPAO. In the striatum and thalamus, Tc-99m ECD and I-123 IMP showed higher lesion sensitivity than Tc-99m HMPAO. I-123 IMP showed the highest lesion contrast in cerebral cortex and cerebellum, whereas Tc-99m ECD showed the highest contrast in thalamus and striatum. In all regions, Tc-99m ECD showed higher lesion contrast than Tc-99m HMPAO. These results suggest regional variation in the sensitivity of lesion detection and lesion contrast of Tc-99m ECD compared to I-123 IMP, and the superiority of Tc-99m ECD to Tc-99m HMPAO.

Topics: Adult; Amphetamines; Cerebellum; Cerebral Cortex; Cerebrovascular Disorders; Cysteine; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organotechnetium Compounds; Oximes; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon

Topics: Cerebrovascular Circulation; Cerebrovascular Disorders; Diagnostic Errors; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon Radioisotopes

Cerebral perfusion deficits detected by injection of 99Tcm-hexamethylpropyleneamine oxime (HMPAO) and single photon emission tomography is said to correlate well with clinical findings in divers with neurological decompression illness. We studied 12 divers. Six had residual cerebral signs (group 1) and six had no residual cerebral symptoms or signs (group 2). Perfusion deficits were as common in group 2 as in group 1. The site of the deficit did not correlate well with either the neurological findings at presentation or the residual clinical signs after treatment. The data suggest that claims that HMPAO scanning correlates with clinical findings and can be used for patients management were incorrect.

Topics: Cerebrovascular Disorders; Decompression Sickness; Diving; Female; Humans; Male; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Tc-99m HMPAO, a lipophilic radiopharmaceutical used for brain imaging, has been reported to localize in smokers' lungs. To quantitate this uptake in the lung, 55 patients, who were referred for brain imaging for dementias or strokes, also underwent lung imaging (anterior lung imaging includes a large part of the liver) after IV injection of the radiopharmaceutical. Regions of interest over the liver and the lung were calculated. Of the 55 patients (ages 13-79), 30 were smokers and 25 were nonsmokers. The smokers had been smoking from 6-59 years, and daily cigarette consumption ranged from 8-50 cigarettes. The mean lung/liver ratio for smoking patients were 0.792 +/- 0.042 (SE); the mean lung/liver ratio for nonsmoking patients was 0.408 +/- 0.019 (SE). Lung/liver ratio uptake was significantly higher in the smoking patients (P < 0.01) than in the nonsmokers. Thus, lung/liver uptake of Tc-99m HMPAO may be used as an indicator of cigarette smoking.

Topics: Adolescent; Adult; Aged; Brain; Cerebrovascular Disorders; Dementia; Female; Humans; Liver; Lung; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Smoking; Technetium Tc 99m Exametazime

A patient developed visual hallucinations following a left-sided cerebrovascular accident (CVA). Brain SPECT using Tc-99m HMPAO demonstrated increased perfusion at the biparieto-occipital lobes. Following antiepileptic medication, repeat brain SPECT showed interval decrease in perfusion in the same areas with the symptomatic relief of hallucinatory episode. While it is possible that the interval decrease is due to natural resolution, the authors believe that it is likely due to drug treatment.

Topics: Aged; Anticonvulsants; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Hallucinations; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Cerebellum; Cerebrovascular Disorders; Electroencephalography; Epilepsy, Temporal Lobe; Female; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Regional Blood Flow; Technetium Tc 99m Exametazime

Our phantom studies indicate that the energy resolution (9.7% FWHM) of a new three-headed single-photon tomograph (PRISM-3000) separates the distribution of 99mTc from 123I for 10% asymmetric or 15% or 10% centered 99mTc windows when combined with a 10% asymmetric 123I window. This technique is now applied to the simultaneous measurement of resting rCBF and changes induced by vasodilation (1 g acetazolamide) in 10 subjects with cerebrovascular disease. Resting and vasodilated 133Xe SPECT images were obtained first. Within 48 hr, 99mTc HMPAO was given at rest, acetazolamide injected, and after 20 min either [123I] IMP or [123I] HIPDM was administered. Subjects were scanned for 99mTc and 123I simultaneously using 10% asymmetric windows. Regression analyses demonstrated a linear relationship between 133Xe SPECT and dual-isotope SPECT measurements of lesion-to-cerebellum ratios in baseline (r = 0.92), vasodilated (r = 0.86) and rest-minus-vasodilated data (r = 0.85). Technetium-99m and 123I images obtained through dual-isotope imaging are by definition in perfect anatomic registration.

Topics: Acetazolamide; Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Iodine Radioisotopes; Iodobenzenes; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasodilation; Xenon Radioisotopes

Insufficiency of collateral supply may lead to low-flow infarcts in severe occlusive cerebrovascular disease. The aim of this study was to evaluate the feasibility of technetium-99m-labeled hexamethylpropyleneamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) to assess hemodynamic compromise in the anterior circulation.. Cerebral blood flow before and after 1 g acetazolamide was analyzed by 99mTc-HMPAO-SPECT in 21 symptomatic patients with documented extracranial obstructions. SPECT findings were correlated with the results of angiography, transcranial Doppler sonography, and computed tomographic scan.. The acetazolamide-induced increase of cerebral blood flow could be reliably monitored by increase of cerebral 99mTc-HMPAO uptake, which varied between 11.4% and 47.6% in the less-affected hemisphere. Increment of hemispheric side-to-side asymmetry of tracer uptake after drug challenge revealed significant restriction of regional vasoreactivity in 11 patients. Agreement in assessing hemodynamic compromise was reached in 81% of patients with ophthalmic artery collaterals on angiography (p < 0.001), in 76% with low-flow infarcts on computed tomographic scan (p < 0.01), and in 91% with markedly reduced flow velocities on transcranial Doppler (p < 0.0001). One patient developed a low-flow infarct in the area predicted by SPECT during follow up.. We conclude that 99mTc-HMPAO-SPECT with acetazolamide challenge is a useful method for assessment of the adequacy of hemispheric collateral pathways in patients with severe occlusive cerebrovascular disease.

Topics: Acetazolamide; Adult; Aged; Arterial Occlusive Diseases; Cerebral Angiography; Cerebrovascular Disorders; Feasibility Studies; Female; Hemodynamics; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ultrasonography; Vasodilation

Tc-99m HMPAO SPECT is more likely to detect a stroke in early stages than CT. However, a conventional HMPAO SPECT study takes at least 30 minutes to complete. This paper compares fast Tc-99m HMPAO SPECT scans and conventional Tc-99m HMPAO SPECT scans with respect to spatial resolution and diagnostic efficacy in vitro and in a small series of patients, respectively. The spatial resolution of fast Tc-99m HMPAO SPECT did not match that of images obtained from conventional SPECT, though the difference proved to be of no clinical significance. Since fast SPECT requires only one-fourth to one-fifth the time necessary for conventional SPECT, it may be more suitable for investigating cases of acute stroke in critical clinical situations.

Topics: Acute Disease; Aged; Brain; Cerebrovascular Disorders; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Models, Structural; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

The detection of bilateral and symmetrical regional cerebral blood flow (rCBF) abnormalities requires knowledge of the antero-posterior rCBF distribution in normal subjects of all age groups. These data are very difficult to obtain in children for ethical reasons and in older subjects because of the necessity of recruiting a large number of healthy volunteers from each age group. Therefore, to obtain normal values of antero-posterior rCBF distribution, we have retrospectively selected a group of patients with a low probability of having cerebral lesions, whose 99mTc-HMPAO brain SPECT studies were analyzed semiquantitatively. Cerebellum/mean cerebral cortex index when compared to young adults was higher in the neonatal period, slightly lower between 2 mo and 15 yr, and more or less identical after 15 yr. Cortico/occipital indexes exhibit considerable changes during the first year of life due to important differences in maturation timing of cerebral cortical areas. After 1 yr, all cerebral cortical areas approximately displayed a parallel evolution. A slight increase in fronto/occipital and temporo/occipital indexes was, however, still observed during childhood, while in elderly subjects there was a trend towards a decrease in all cortico/occipital indexes (particularly in prefrontal and motor areas). Changes that occurred after 1 yr were, however, usually smaller than interindividual variation. Despite the large range of "normal" values, the antero-posterior analysis could be useful in various neurologic disorders, because it allows detection of symmetrical rCBF anomalies undiagnosed by the right-left analysis.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Belgium; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Child, Preschool; Humans; Infant; Infant, Newborn; Middle Aged; Organotechnetium Compounds; Oximes; Reference Values; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Brain SPECT perfusion studies in patients with cerebral stroke may be useful to evaluate distant perfusion abnormalities.. 99mTc-HMPAO brain SPECT studies were performed in 17 patients with ischemic lesions in the basal ganglia and/or internal capsule demonstrated by NMR. Regions of interest were adjusted in representative transverse slices to the vascular territories of the anterior, middle, posterior and communicating cerebral arteries.. Patients with ischemic lesions in the right basal ganglia showed increased cerebral perfusion in the left middle artery territory (0.95 +/- 0.13 versus 0.80 +/- 0.06; p = 0.0365). Patients with ischemic lesions in the left basal ganglia showed increased perfusion in the right anterior artery territory (0.93 +/- 0.09 versus 0.82 +/- 0.09; p = 0.0464), in the left anterior artery territory (0.93 +/- 0.09 versus 0.83 +/- 0.14; p = 0.0464), in the left middle artery territory (0.92 +/- 0.09 versus 0.78 +/- 0.05; p = 0.0079) and in the left posterior artery territory (1.05 +/- 0.14 versus 0.90 +/- 0.09; p = 0.036). Patients with ischemic lesions in the right internal capsule showed increased perfusion in the right posterior artery territory (0.95 +/- 0.11 versus 1.10 +/- 0.18; p = 0.0431).. These results show the presence of delayed luxury perfusion phenomena in regions distant from the ischemic site.

Topics: Aged; Aged, 80 and over; Brain; Brain Ischemia; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A non-invasive, simple method for the quantitative evaluation of brain perfusion is presented using intravenous radionuclide angiography with technetium-99m hexamethylpropylene amine oxime (99mTc-HM-PAO). Graphical analysis was employed for the evaluation of the unidirectional influx constant (ku) of the tracer from the blood to the brain. The ku values were standardized to provide objective and comparable values, brain perfusion indices (BPI), among studied subjects by setting the ratio of ROIbrain size to ROIaorta size at 10. The whole-brain BPI values for the normal control subjects showed a significant negative correlation with advancing age (r = -0.632, P = 0.0204, n = 13). The mean of the whole-brain BPI of 7.0 (SD = 1.4) in 20 patients with cerebrovascular disorders was significantly lower than that of 10.6 (SD = 1.5) in 13 normal control subjects. The BPI measurements showed only minimal intra- and interobserver variability. Changes of the ratio of ROIaorta size and ROIbrain size did not significantly influence the BPI values. Hemispherical BPI values in 19 subjects (n = 38) showed highly significant correlations with the hemispherical mean cerebral blood flow values obtained from Xenon-133 single photon emission tomography (SPET) (r = 0.926, P = 0.0001 for the early picture method and r = 0.932, P = 0.0001 for the sequential picture method). This technique is easy to apply as an adjunct to SPET and may be helpful in the quantitative evaluation of brain perfusion in routine clinical studies.

Topics: Adult; Aged; Aged, 80 and over; Blood Flow Velocity; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Angiography; Technetium Tc 99m Exametazime

The effects of acetazolamide (Diamox) on vascular response were investigated in areas with intrahemispheric thalamic diaschisis and crossed cerebellar diaschisis using consecutive Tc-99m HMPAO brain SPECT studies before and after Diamox administration. All six patients with thalamic diaschisis and five of eight patients with crossed cerebellar diaschisis at baseline showed significantly augmented perfusion after Diamox administration in the affected thalamus and cerebellum compared with that in the contralateral unaffected areas. These results suggest more dilatation of the arterioles in areas with diaschisis after Diamox administration than in areas without diaschisis. Diamox may produce relative luxury perfusion in areas with diaschisis.

Topics: Acetazolamide; Adult; Aged; Cerebellar Diseases; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Thalamic Diseases; Tomography, Emission-Computed, Single-Photon

Sixty patients were studied for carotid artery disease and were further evaluated with hexamethyl-propyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) both at baseline (with the patient resting) and after administration of acetazolamide (ACZ). Of these 60 patients, 58 (97%) had symptoms and 49 (82%) had stenoses greater than 70% in at least one internal carotid vessel. Nine patients (15%) had symmetric findings on baseline examinations and at SPECT with ACZ. Thirty-two patients (53%) had asymmetric findings on baseline, but in 24 of these patients (75%) additional lesions were observed after ACZ administration. Nineteen patients (32%) had asymmetric findings only after ACZ was administered. HMPAO SPECT with ACZ allows detection of diminished cerebral perfusion reserve that is not found when HMPAO SPECT is performed with the patient at rest. This procedure helps provide an objective evaluation of the hemodynamic effects of carotid stenosis.

Topics: Acetazolamide; Adult; Aged; Aged, 80 and over; Arterial Occlusive Diseases; Carotid Artery Diseases; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We report the SPECT, CT and CW Doppler findings in a series of 117 patients with cerebral ischemic lesions and correlate them with the clinical findings. SPECT-PAO proved to be more sensitive in localizing focal lesions than CT, which in 50% of the cases was normal or yielded an image of cerebral atrophy. In the latter cases CW Doppler ultrasound on the supraaortic trunks showed changes, circumscribed or diffuse. On the CW Doppler and SPECT evidence we consider that the CT image of cerebral atrophy may denote an alteration of the cerebral blood flow and metabolism and should be assessed in this light in the diagnosis and prognosis of cerebral ischemic lesions.

Topics: Adult; Aged; Atrophy; Blood Flow Velocity; Brain; Brain Ischemia; Cerebral Angiography; Cerebrovascular Disorders; Evaluation Studies as Topic; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ultrasonography

Lacunar infarctions and periventricular hypodensity are assumed to be typical CT patterns of cerebral microangiopathy (MA). In 17 patients with such findings and in 6 controls without any signs of central nervous system disease cranial CT, MRT and 99mTc-HMPAO-SPECT were employed. Seven patients with CT findings of minor MA demonstrated in comparison to controls no significant difference. In 10 cases with CT findings of pronounced MA periventricular rCBF was significantly reduced compared to controls. rCBF of temporal and parietal cortex was not diminished compared to controls. In 14 patients studied with MRT deep white matter lesions were found which appeared solitary, multiple or confluent. Employing 99mTc-HMPAO-SPECT, cerebral MA revealed rCBF reduction in periventricular brain tissue by cerebellar standardization.

Topics: Aged; Aged, 80 and over; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A review of our 1 1/2 years' experience with transcranial Doppler sonography (TCD) is given. In total, 619 TCD examinations were performed. Considering physiological variations of blood flow velocities in the intracranial arteries, TCD findings in stenoses and occlusions of the extracranial and intracranial brain-supplying arteries as well as in intracranial vasospasms were evaluated. In patients with leptomeningeal anastomoses demonstrated by TCD in the region of the peripheral middle cerebral artery, the regional cerebral blood flow was measured by 99mTc-HMPAO-SPECT. The value and limitations of TCD in cerebrovascular diseases and the indications to TCD examination of the intracranial arteries are discussed.

Topics: Carotid Artery Diseases; Carotid Artery, External; Carotid Artery, Internal; Cerebrovascular Disorders; Constriction, Pathologic; Echoencephalography; Evaluation Studies as Topic; Humans; Organotechnetium Compounds; Oximes; Subclavian Steal Syndrome; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A method for registering three-dimensional CT, MR, and PET data sets that require no special patient immobilization or other precise positioning measures was adapted to high-resolution SPECT and MRI and was applied in 14 subjects (five normal volunteers, four patients with dementia (Alzheimer's disease), two patients with recurrent glioblastoma, and three patients with focal lesions (stroke, arachnoid cyst and head trauma]. T2-weighted axial magnetic resonance images and transaxial 99mTc-HMPAO and 201Tl images acquired with an annular gamma camera were merged using an objective registration (translation, rotation and rescaling) program. In the normal subjects and patients with dementia and focal lesions, focal areas of high uptake corresponded to gray matter structures. Focal lesions observed on MRI corresponded to perfusion defects on SPECT. In the patients who had undergone surgical resection of glioblastoma followed by interstitial brachytherapy, increased 201Tl corresponding to recurrent tumor could be localized from the superimposed images. The method was evaluated by measuring the residuals in all subjects and translational errors due to superimposition of deep structures in the 12 subjects with normal thalamic anatomy and 99mTc-HMPAO uptake. This method for superimposing magnetic resonance and high-resolution SPECT images of the brain is a useful technique for correlating regional function with brain anatomy.

Topics: Alzheimer Disease; Arachnoid Cysts; Brain; Brain Injuries; Cerebrovascular Disorders; Glioma; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Topics: Acetazolamide; Adolescent; Adult; Aged; Brain; Cerebrovascular Disorders; Child; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Perfusion; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We have performed initial clinical studies using the high resolution single photon ring tomograph (SPRINT) and Tc-99m HMPAO. To determine what additional anatomic detail can be depicted using this high resolution, dedicated head, multidetector SPECT device compared to conventional SPECT, six patients with stroke and one normal volunteer were imaged after the injection of 20 mCi Tc-99m HMPAO on a conventional rotating Anger gamma camera (GE-400AC), followed immediately by imaging on SPRINT. Imaging acquisition on the GE-400AC gamma camera was performed using 360 degrees rotation, 64 stops, at 30 sec/stop, yielding an average of 985,714 counts for a 10.0 mm thick slice. GE-400AC images were of good quality, having in-plane full width half maximum (FWHM) resolution of approximately 15 mm. SPRINT acquisition of image data was performed using both the high resolution and high sensitivity apertures, with data collection over 15 or 20 minutes of imaging time accumulating approximately 500,000 counts and 1,000,000 counts, respectively, from patients in a 10.0 mm thick slice, achieving an in-plane FWHM resolution of approximately 8 mm and 10 mm for the two apertures, respectively. Both image resolution and contrast for visualization of gray, white, and cerebral spinal fluid filled brain structures were improved using SPRINT compared with the GE-400AC. We conclude that SPRINT is well suited for brain imaging with Tc-99m HMPAO and is of particular value for applications demanding high resolution.

Topics: Adult; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Gamma Cameras; Humans; Male; Middle Aged; Models, Structural; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Sixty-five patients referred for Tc-99m HMPAO SPECT brain perfusion studies had measurements of global Tc-99m HMPAO retention after injection at rest and after acetazolamide pretreatment. Acetazolamide produced relative changes in Tc-99m HMPAO retention similar to those previously reported with Xe-133 regional cerebral blood flow (rCBF) measurements. This addition to imaging protocols allows another objective evaluation of the cerebral vascular reserve.

Topics: Acetazolamide; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Stimulation, Chemical; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

This report describes a new approach to the evaluation of brain perfusion reserve using Tc-99m HMPAO SPECT. Consecutive brain Tc-99m HMPAO SPECT studies before and after acetazolamide (Diamox) administration were performed within 30 minutes on 19 patients with significant vascular occlusive lesions. Thirteen patients showed decreased perfusion reserve and four patients maintained perfusion reserve in the affected vascular territories after Diamox administration, providing additional information to baseline Tc-99m HMPAO SPECT in 17 (89%) patients. Although flow augmentation post-Diamox was underestimated, possibly due to the nonproportionality of Tc-99m HMPAO activity to true blood flow, significant changes in the brain perfusion pattern were both visually and quantitatively determined using an image subtraction technique. This consecutive Tc-99m HMPAO SPECT technique seems to be of practical use for the evaluation of brain perfusion reserve and for the improvement of the sensitivity of detecting pathologic areas.

Topics: Acetazolamide; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Evaluation Studies as Topic; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Reproducibility of Results; Sensitivity and Specificity; Stimulation, Chemical; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Tc-99m HMPAO, a lipophilic radiotracer used as a brain SPECT imaging agent in the diagnosis of strokes and dementias, is normally localized in the brain and the heart and is excreted through the kidneys (50%) and the hepatobiliary system (14% to 30%). There is no pulmonary localization except in the lungs of smokers. To evaluate pulmonary localization of Tc-99m HMPAO in relation to smoking, 23 patients (aged 27 to 76 years) who were referred for brain imaging studies for strokes or dementias also underwent lung imaging studies immediately following the brain imaging. Anterior and/or posterior lung images were obtained 30 to 45 minutes after IV injection of 15 mCi Tc-99m HMPAO. Diffuse pulmonary uptake was graded semiquantitatively: 3+, pulmonary uptake is equal to or higher than hepatic uptake; 2+, pulmonary uptake is less than hepatic uptake but higher than cardiac uptake; 1+, pulmonary uptake is equal to cardiac uptake; 0, pulmonary uptake is less than cardiac uptake. Each patient's smoking history, including duration and daily consumption, was recorded. Four patients' lung images showed 3+ lung uptake; 6 patients, 2+; 1 patient, 1+; and 12 patients, 0 uptake. Eleven patients with lung uptakes of 3+ to 1+ had a history of cigarette smoking. Twelve patients with lung uptake less than cardiac uptake had no smoking history. Pulmonary distribution of Tc-99m HMPAO is usually negligible in the normal lung. Our results indicate that lung uptake correlates significantly (chi-square = 23, d.f. = 1, P = 0.0001) with smoking history.

Topics: Adult; Aged; Brain; Cerebrovascular Disorders; Dementia; Humans; Lung; Male; Organotechnetium Compounds; Oximes; Smoking; Technetium Tc 99m Exametazime; Tissue Distribution; Tomography, Emission-Computed, Single-Photon

Sneddon syndrome is a non-inflammatory, non-atherosclerotic disease involving small and medium-sized arteries of the brain and of the skin. The arteriographic examination is often negative despite progressive impairment of the neurological status. In 3 patients with Sneddon syndrome cerebral perfusion was assessed with single photon emission computerized tomography (SPECT) and technetium99 m-hexamethylpropylenamineoxime (Tc99 HM PAO). A correlation between clinical and SPECT finding was found, with significant focal reduction of regional cerebral blood flow (rCBF) in the two more severely affected patients.

Topics: Adult; Brain; Cerebrovascular Disorders; Female; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Perfusion; Skin Diseases; Syndrome; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Twenty-two patients with completed stroke were studied to evaluate the clinical usefulness of three-dimensional (3D) surface display in brain imaging with Tc-99m HM-PAO. Perfusion defects were seen by standard 3D surface display in all 13 patients, with low density areas (LDA) extending to the cerebral cortex on X-ray computed tomography. In nine patients with LDA limited around the basal ganglia, perfusion defects were not identified by standard display alone, but six were found to have such defects by 3D surface display minus the covering upper structure. This study indicates that standard 3D surface display is useful in stereoscopically evaluating cortical defects without searching through a large number of single photon emission computed tomographic (SPECT) images. Moreover, 3D surface display minus the upper structure is effective to demonstrate defects within the brain.

Topics: Adult; Aged; Brain; Cerebrovascular Disorders; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Amphetamines; Cerebrovascular Disorders; Humans; Iodine Radioisotopes; Iofetamine; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The paper is concerned with the results of single-photon emission tomography and gamma-topography in patients with cerebral tumors, cerebral circulatory disorders and pathology of the liquor system. Tomographic investigation was shown to enhance the accuracy and reliability of the detection of cerebral tumors. Single-photon emission computerized gamma-tomography (SPECT) permitted the detection of structural and morphological cerebral changes in disturbed cerebral circulation of various etiology. SPECT together with computerized tomography and radionuclide cisternography was shown to be an auxiliary method for visualization of the cerebral cisterns. Radionuclide tomographic images as compared to gamma-topographic findings of the brain possessed a high statistical significance and good resolution.

Topics: Adult; Brain; Brain Neoplasms; Cerebrospinal Fluid; Cerebrovascular Disorders; Evaluation Studies as Topic; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Sodium Pertechnetate Tc 99m; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single-photon emission computed tomography (SPECT) of the brain using hexamethyl propylene amine oxime (HMPAO) was performed in a 37-year-old patient suffering from mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). Reduced blood flow was observed bilaterally in the parieto-occipital regions (resembling Alzheimer type dementia) and in the right parietal lobe.

Topics: Acidosis, Lactic; Adult; Alzheimer Disease; Brain Diseases; Cerebrovascular Disorders; Diagnosis, Differential; Humans; Male; Mitochondria, Muscle; Organotechnetium Compounds; Oximes; Syndrome; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

This study investigated the possibility that a relationship between the anatomic defects observed on computed tomography (CT) and the functional defects observed on single photon emission computed tomography (SPECT) might be used as an outcome measure to predict clinical recovery from the neurologic deficits induced by stroke. Twenty-seven patients with stroke location limited primarily to cerebral cortex were included in the study: each patient underwent a cranial CT scan, 99mTc hexamethylpropyleneamineoxime SPECT cerebral perfusion scan, and an initial and 1-yr follow-up neurologic examination. A strongly positive correlation between the ratio of the SPECT to CT volume defect sizes (SPECT divided by CT) and recovery following stroke was found, such that the greater the SPECT to CT ratio, the better the subsequent recovery of neurological deficits. Discriminant function analysis revealed that the best predictor of clinical outcome following stroke was the log-transformation of SPECT divided by CT. The results suggest that the relationship between the perfusion defects and tissue loss measured by SPECT and CT imaging may have prognostic utility following stroke limited primarily to cerebral cortex.

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Neurologic Examination; Organotechnetium Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

In this pilot study of poststroke depression, the authors evaluated regional cerebral blood flow and depression in 14 stroke patients. Volume of ischemia was measured by two methods, which were highly correlated. Depression scores correlated with lesion volume as measured by single photon emission CT.

Topics: Adult; Aged; Aged, 80 and over; Cerebrovascular Circulation; Cerebrovascular Disorders; Depressive Disorder; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Pilot Projects; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

To compare the merits of 123I-isopropyl-iodoamphetamine (123I-IMP) and 99mTc-HMPAO in showing abnormal brain uptake distribution during cerebral ischemia, we studied ten patients during the subacute phase of their stroke, a period where metabolism and blood flow are frequently uncoupled. SPECT imaging was performed using both radiopharmaceuticals in the 10 patients from 48 h to 4 weeks after onset of symptoms. Two patients out of the 10 had similar defects with 123I-IMP and 99mTc-HMPAO SPECT, the location of the defects corresponding to the area of infarction observed on CT. Six patients had normal 99mTc-HMPAO SPECT and abnormal 123I-IMP SPECT with defects in the area of infarction shown by CT. The remaining 2 patients had hyperactive abnormalities on 99mTc-HMPAO in areas corresponding to defects on the 123I-IMP images. Two of the patients with SPECT mismatches were studied again more than 1 month after onset. On reexamination, 99mTc-HMPAO SPECT which was previously normal or hyperactive became hypoactive with a focal area of decreased activity corresponding to the defect on 123I-IMP. Crossed cerebellar diaschisis was found in 7 patients with 99mTc-HMPAO and was absent for both 123I-IMP and 99mTc-HMPAO in 3. We suggest that SPECT with 99mTc-HMPAO could show transient hyperemia not demonstrated by 123I-IMP whereas in some cases cerebral infarction would be more difficult to demonstrate with 99mTc-HMPAO than with 123I-IMP. SPECT with both tracers is recommended to follow the evolution of strokes in terms of regional cerebral blood flow and tissue metabolism.

Topics: Adult; Aged; Aged, 80 and over; Amphetamines; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The first data acquisition method for Tc-99m hexamethylpropyleneamineoxime (Tc-99m HMPAO) brain SPECT was used in two patients with acute stroke 5 and 8 hours after the event. In one patient Tc-99m HMPAO fast SPECT showed perfusion defects before the same was manifested on CT. In the other patient, Tc-99m HMPAO fast SPECT showed larger defects than the edema seen on CT. The Tc-99m HMPAO fast SPECT might be feasible for the evaluation of acute stroke patients. Since the time required for fast SPECT is much shorter than usual SPECT, it appears to be more suitable for some patients with acute stroke who are brought to the hospital in a very critical condition.

Topics: Aged; Brain; Cerebral Angiography; Cerebrovascular Disorders; Female; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Regional cerebral blood flow (rCBF) alterations, as determined by single photon emission computed tomography (SPECT) using technetium Tc 99m hexamethyl propylenamine oxime (Tc 99m-HM-PAO), were studied in 15 infants and children presenting with cerebrovascular disorders between the ages of 2 weeks and 16 years. The rCBF patterns were correlated with clinical presentation, electroencephalographic patterns, radiologic studies, including computed tomography and magnetic resonance imaging of the head, and cerebral angiography. All patients presented with motor weakness that was accompanied in some with dysphasia, defects in visual fields, obtundation, seizures, and high temperature. Perturbations of rCBF with Tc 99m-HMPAO SPECT brain scanning were detected in all patients investigated, with no adverse effects related to the radiotracer. All patients had a focal area of decreased rCBF, with adjacent hyperemia in 3 patients. In 7 patients, there was an rCBF decrease in a vascular distribution, mainly that of the middle cerebral artery, that correlated with the clinical findings and a focal electroencephalogram, as well as computed tomography and magnetic resonance imaging of the head. Impairment of rCBF was more extensive in 3 children, while early abnormal SPECT findings preceded abnormal computed tomographic findings in another 2 children. In 2 patients, Tc 99m-HMPAO SPECT was the only positive radiologic test to correlate with focal clinical and electroencephalographic abnormalities, in view of repeated normal computed tomographic scans. We conclude that Tc 99m-HMPAO SPECT brain scanning is a sensitive, complementary diagnostic measure in the early detection, localization, and estimation of rCBF alterations in pediatric cerebrovascular disease.

Topics: Cerebrovascular Circulation; Cerebrovascular Disorders; Child, Preschool; Electroencephalography; Humans; Infant; Magnetic Resonance Imaging; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

The authors presented clinical material on cerebral hemodynamics in patients with neurological pathology in suspected tumor vascular cerebral diseases and craniocerebral traumas. Investigation of cerebral microcirculation was performed using a multidetector single-photon emission tomograph "Testoscan" (USSR) after iv administration of 99mTc-hexamethylpropilene-amyloxine. This radiopharmaceutical is good for the evaluation of cerebral perfusion and gives a clinician rich information on cerebral microcirculation.

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Drug Evaluation; Head; Humans; Intracranial Aneurysm; Ischemic Attack, Transient; Microcirculation; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Positron emission tomography (PET) of [18F]fluoromethane (FM) and single-photon emission tomography (SPECT) of [99mTc]hexamethylpropyleneamine oxime (HMPAO) were performed under identical conditions within 2 h in 22 patients suffering from cerebrovascular disease (8 ischemic infarction, 2 intracerebral hemorrhages, 7 transient ischemic attacks, and 5 multi-infarct syndrome). While gross pathological changes could be seen in the images of either procedure, focal abnormalities corresponding to transient ischemic deficits or to lesions in multi-infarct syndrome and areas of functional deactivation were sometimes missed on SPECT images. Overall, HMPAO SPECT images showed less contrast between high and low activity regions than the FM PET images, and differences between lesions and contralateral regions were less pronounced (6.4 vs 13.3% difference). Regional cerebral blood flow (rCBF) was calculated from FM PET studies in 14 large territorial regions and the pathological lesion, and the regional values relative to mean flow were compared to the relative HMPAO uptake in an identical set of regions defined on the SPECT images. Among individual patients, the Spearman rank-correlation coefficient between relative rCBF and HMPAO uptake varied between 0.48 and 0.89, with a mean of 0.70. While an underestimation of high flow with SPECT--which was demonstrated in a curvilinear relationship between all relative regional PET and SPECT values--could be corrected by linearization taking into account HMPAO efflux from the brain before metabolic trapping, correspondence of SPECT data with PET rCBF values was not improved since this procedure also increased the variance in high flow areas. In the cerebellum, however, a high HMPAO uptake in SPECT always overestimated CBF in relation to forebrain values; this finding might be due to high capillary density in the cerebellum. The differences observed between SPECT and PET data may be explained by technical and physical properties of the methods and by the incomplete first-pass extraction of HMPAO. Additionally, HMPAO or its metabolites may leak through a damaged blood-brain barrier (as observed in one infarct and in the surrounding of hemorrhages), impairing the contrast between lesion and normal tissue. The presented data indicate that the quantification of rCBF by HMPAO SPECT is limited.

Topics: Adult; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Fluorine Radioisotopes; Humans; Hydrocarbons, Fluorinated; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

We performed single photon emission computed tomography (SPECT) and cerebral CT-scans in nine patients with hereditary cerebral amyloid angiopathy. CT-scans showed 23 focal hypodense lesions, 13 of which were visible on SPECT as a CBF-defect. One patient showed a CBF-defect on SPECT without CT-scan lesion and had a cerebral hemorrhage three months later in that particular region. In two additional patients, who were 50% at risk for this autosomal dominant disease, CBF-defects on SPECT, but no cortical lesions on CT-scan were found. CT-scans may be more sensitive than SPECT to detect chronic lesions caused by cerebral hemorrhages, but another possibility is that hemorrhages do not always lead to persistent CBF-defects. SPECT can show the effect of amyloid deposits on CBF before the angiopathy causes clinical symptoms.

Topics: Amyloidosis; Brain Diseases; Cerebral Hemorrhage; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Single-Blind Method; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

In a retrospective study the sensitivity of SPECT and CT in detecting changes in cerebrovascular disease is compared, based on a group of one hundred patients. The higher sensitivity of SPECT with regard to right-positive results, especially in TIA and PRIND and the markedly lower number of false-negative results are underlined and discussed. The fact that both methods reveal only a slight sensitivity regarding the detection of changes in the basal regions of the brain is also pointed out, with SPECT proving to be the more sensitive of the two methods.

Topics: Adult; Aged; Brain; Brain Ischemia; Cerebrovascular Disorders; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Topics: Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Organometallic Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Aged; Cerebrovascular Disorders; Female; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Blood-Brain Barrier; Cerebrovascular Disorders; Humans; Organometallic Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

A study was made of the cerebral hemodynamics by assessing the distribution in single-photon emission computerized tomography with 99mTc-hexamethyl-propyleneminoxyne in health using a Testascan in 9 standard slices. The whole set of tomographic slices was conventionally divided into 3 levels. For better orientation in gamma-tomographic images, pictures were presented where in addition to scintigrams a morphological scheme of the cerebral parts with the marked parts perfused by cerebral arteries, was given.

Topics: Brain; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Contrast Media; Hemodynamics; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

In 16 patients with reversible symptoms of cerebrovascular disease a HMPAO- and/or IMP-SPECT was performed. 12 of these patients were suffering from TIA, 4 from PRIND. Using HMPAO-SPECT in 8 out of 9 patients with TIA and in 1 of 2 with PRIND a hypoperfusion could be demonstrated; IMP-SPECT showed a pathological pattern in 3 of 5 patients with TIA and in none of 2 patients with PRIND. A semiquantitative evaluation showed a tracer accumulation reduced by 13 +/- 12% (HMPAO) and 8 +/- 7% (IMP), respectively, in the clinically involved hemisphere, compared to the contralateral side. In circumscript SPECT lesions a reduction by 21 +/- 8% (HMPAO) or 17 +/- 7% (IMP) was observed. The interhemispheric ratio from the HMPAO-SPECT showed a significant correlation to that of the 133Xe-rCBF measurement (r = 0.86; p less than 0.001). SPECT was positive in a higher percentage than TCT, Doppler sonography, radioangiography and 133Xe-rCBF measurement. This does not imply a higher specificity or sensitivity, because a slight inhomogeneous SPECT pattern may occasionally be observed even in normal persons.

Topics: Adult; Aged; Amphetamines; Brain Ischemia; Cerebrovascular Disorders; Female; Humans; Iodine Radioisotopes; Iofetamine; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

In order to evaluate the diagnostic contribution of brain SPECT imaging with 99mTc-HMPAO in cerebrovascular disease, we examined 92 stroke cases (144 lesions), 2 hematoma cases and 30 cases with transient neurologic symptoms. Abnormal tracer distribution is visible as zones of either hypoactivity or hyperactivity (border zone hyperemia or luxury perfusion). Remote vascularization changes could also be found (crossed cerebellar diaschisis or ipsilateral cortical perfusion reduction in thalamic or capsula interna lesions). Both X-ray CT and blood flow SPECT have comparable sensitivity in the exploration of cerebral infarction, with detection in, respectively, 89.5% and 87.5% of the lesions. False negative scintitomographic images are frequently recorded in small lacunar infarcts within the basal ganglia and white matter (capsula interna). Some early infarcts and asymmetry of brain perfusion in patients with transient neurologic symptoms are frequently not detected by CT. An additional advantage of blood flow SPECT is its ability to visualize remote blood flow changes and the changing pattern of vascularization of ischemic lesions and their surrounding areas including hyperemia.

Topics: Brain; Cerebrovascular Disorders; Humans; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

A consistent method for the qualitative analysis of regional cerebral blood flow on single-photon emission computed tomography (SPECT) imaging has not yet been realized. Regional analysis usually refers an area of abnormal tracer uptake to another region of brain (e.g., the contralateral hemisphere), but region of interest size and analysis differ between investigators. In patients who have had a stroke, the flow deficit size on the SPECT image often appears much larger than the abnormality visualized on computed tomography (CT), and confounds attempts to differentiate between "purely" infarcted brain tissue, ischemic brain tissue, edema, or brain tissue having diminution of flow resulting from deafferentation. The author presents a method to determine a flow deficit volume that can be easily calculated from the SPECT image, which yields a volume size that is equivalent to a hypothetical volume having zero blood flow. The method of calculation is objective, independent of region of interest size, and provides a SPECT volume deficit that may be correlated with the CT volume deficit, thus helping to differentiate "purely" infarcted tissue from tissue having infarction, edema, ischemia, and deafferentation.

Topics: Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Male; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed

Regional cerebral blood flow (rCBF) was measured by single photon emission computed tomography (SPECT) using 133Xe, N-isopropyl-p-[123I]iodoamphetamine ([123I]IMP) and [99mTc] hexamethylpropyleneamine oxime ([99mTc]HM-PAO) in 24 patients with cerebrovascular diseases. The greatest advantage of 133Xe SPECT was to be able to provide absolute rCBF values without arterial sampling. However, its image quality was very poor. Iodine-123 IMP SPECT provided rCBF images of higher quality and it had good correlation to 133Xe SPECT. Iodine-123 IMP SPECT provided the best images to detect mild ischemic lesions. It could detect obstructive or stenotic changes of large cerebral arteries very well except for a moderate stenosis of internal carotid artery. Technetium-99m HM-PAO SPECT also provided very good rCBF images and it had good correlation to 133Xe SPECT. However, the count-density ratios for the ischemic lesions to the contralateral presumed normal areas of [99mTc] HM-PAO SPECT were significantly higher than those of [123I]IMP SPECT.

Topics: Adult; Aged; Aged, 80 and over; Amphetamines; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Xenon Radioisotopes

Topics: Brain; Cerebrovascular Disorders; Child; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A new radiotracer of cerebral perfusion, 99mTc-labelled hexamethylpropylene amine-oxime, has been tried in 78 subjects: 6 controls and 72 patients. Qualitatively, the distribution of this tracer in healthy subjects was very much the same as that obtained with a reference method using 133xenon inhalation. Quantitatively, there was no correlation between the real blood flow rate and the normalized cerebral uptake rate. On the other hand, the asymmetry indices obtained in controls (but also in 16 patients) correlated very closely with those obtained with 133xenon. Our first results in acute ischaemic diseases as well as in the evaluation of vasospasm or Alzheimer-like presenile dementia point to wide fields of application for the new compound. Unlike its predecessors, it is always available and will probably be used, without any logistic investment, with the standard equipment of all Nuclear medicine departments.

Topics: Adult; Aged; Aged, 80 and over; Alzheimer Disease; Brain Ischemia; Cerebral Hemorrhage; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Hematoma; Humans; Ischemic Attack, Transient; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Aged; Cerebral Angiography; Cerebrovascular Disorders; Humans; Ischemic Attack, Transient; Middle Aged; Organometallic Compounds; Oximes; Radiographic Image Enhancement; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed; Ultrasonography

The radioisotope distribution following intravenous injection of 99mTc-labeled hexamethylpropyleneamine oxime (HM-PAO) in the brain was measured by single photon emission computed tomography (SPECT) and corrected for the nonlinearity caused by differences in net extraction. The "linearization" correction was based on a three compartment model, and it required a region of reference to normalize the SPECT image in terms of regional cerebral blood flow distribution. Two different regions of reference, the cerebellum and the whole brain, were tested. The uncorrected and corrected HM-PAO images were compared with cerebral blood flow (CBF) image measured by the C15O2 inhalation steady state method and positron emission tomography (PET). The relationship between uncorrected HM-PAO and PET-CBF showed a correlation coefficient of 0.85 but tended to saturate at high CBF values, whereas it was improved to 0.93 after the "linearization" correction. The whole-brain normalization worked just as well as normalization using the cerebellum. This study constitutes a validation of the "linearization" correction and it suggests that after linearization the HM-PAO image may be scaled to absolute CBF by employing a global hemispheric CBF value as measured by the nontomographic 133Xe clearance method.

Topics: Adult; Aged; Algorithms; Brain; Carbon Dioxide; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Oxygen Radioisotopes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

In 53 patients with cerebrovascular disease (CVD), regional cerebral blood flow (CBF) and blood volume (CBV) were imaged by SPECT within one session. Slice division (CBF: CBV) yielded distribution of regional cerebral perfusion reserve (CPR). Semiquantitative evaluation was obtained from manually set ROIs by interhemispherical ratios (for CBF, CBV and CPR), using 2 SD from a normal group (n = 10) as a threshold. Sensitivities were 59% for CBF, 94% for CBV and 83% for CPR. Combined sensitivity was 98%. Establishing three constellations for CBF, CBV and CPR, regionally normal CBFs but quantitatively increased CBVs (+69%) and decreased CPRs (-31%) were found in relatively early stages of CVD. Very advanced cases showed decreased CBFs (-65%), CBVs (-40%), CPRs (-49%) and a surrounding penumbra. In 87% (46/53 patients), such rheologically postulated constellations could be demonstrated. We conclude that combined CBF and CBV SPECT, assisted by CPR images, is a promising tool to detect CVD and to assess its individual regional severity.

Topics: Aged; Blood Volume; Cerebrovascular Circulation; Cerebrovascular Disorders; Erythrocytes; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Perfusion; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Regional cerebellar perfusion was imaged using technetium Tc 99m hexamethylpropylene amine oxime and single photon emission computed tomography (HM-PAO-SPECT) in a patient with chronic left lateral medullary syndrome with contralateral weakness due to traumatically induced thrombosis of the left vertebral artery. Despite continued neurologic deficits, x-ray transmission computed tomography was normal. However, HM-PAO-SPECT demonstrated that blood flow to the left cerebellar hemisphere was significantly impaired. This abnormality was still apparent after correction for atrophy as estimated by magnetic resonance imaging. Technetium Tc 99m hexamethyl-propyleneamine oxime and single photon emission computed tomography effectively imaged regional blood flow in the vertebrobasilar circulation and appears to more clearly reflect the nature and extent of the neurologic deficit than either x-ray transmission computed tomography or magnetic resonance scanning.

Topics: Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Aged; Aged, 80 and over; Amphetamines; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Xenon Radioisotopes

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed

Topics: Adult; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Predictive Value of Tests; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Aged; Cerebrovascular Disorders; Female; Humans; Iodobenzenes; Ischemic Attack, Transient; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed

Topics: Blood Flow Velocity; Brain; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

In order to validate the use of technetium-99m-d,l-hexamethylpropyleneamine oxime (HM-PAO) as a flow tracer, a total of 21 cases were studied with single photon emission computerized tomography (SPECT), and compared to regional cerebral blood flow (rCBF) measured by position emission tomography (PET) using the oxygen-15 CO2 inhalation technique. Although HM-PAO SPECT and rCBF PET images showed a similar distribution pattern the HM-PAO SPECT image showed less contrast between high and low activity flow regions than the rCBF image and a nonlinear relationship between HM-PAO activity and rCBF was shown. Based on the assumption of flow-dependent backdiffusion of HM-PAO from the brain, we applied a "linearization algorithm" to correct the HM-PAO SPECT images. The corrected HM-PAO SPECT images revealed a good linear correlation with rCBF (r = 0.901, p less than 0.001). The results indicated HM-PAO can be used as a flow tracer with SPECT after proper correction.

Topics: Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Models, Cardiovascular; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tissue Distribution; Tomography, Emission-Computed

Seventeen patients who had suffered a stroke in the previous 72 h have been studied using technetium 99m hexamethyl propylene amine oxime (HMPAO) to assess cerebral blood flow. Comparison of the scan appearances and clinical signs were made in all cases. Twelve of the patients had a repeat HMPAO scan 14 days later, together with further clinical assessment. Good correlation between the size and site of perfusion deficit and the clinical signs was found in 14 of the patients. When the results of the 12 patients who had repeat scans were examined at 14 days the correlation between the scan and the clinical signs was less accurate and it seems unlikely that the assessment of the size of cerebral infarction as demonstrated by an HMPAO scan will provide an accurate prognostic sign. Three of the patients, all of whom had suffered right hemiplegia and were dysphasic, had regions of increased uptake adjacent to the area of ischaemia and non deteriorated clinically; it is thought that this sign may represent hyperperfusion around infarction and indicates a fair prognosis. In patients suffering from transient neurological symptoms, the use of HMPAO may be useful by excluding the presence of other cerebral disease.

Topics: Aged; Aged, 80 and over; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Topics: Adult; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Epilepsy; Humans; Organometallic Compounds; Oximes; Sodium Pertechnetate Tc 99m; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Cerebrovascular Disorders; Female; Humans; Middle Aged; Organometallic Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime; Tomography, X-Ray Computed

Technetium-99m hexamethylpropyleneamineoxime ([99mTc]HM-PAO) brain single photon emission computed tomography (SPECT) was performed with a dual head rotating scintillation camera. Normal tracer distribution and side/side differences of counting rates were obtained in 11 healthy volunteers. Almost stable gray/white matter ratios were found (1.97-2.1) in one normal subject during 2 hr after tracer administration. Eighty-three investigated patients had the following diagnoses (in parentheses is percent of positive findings in each group): cerebral vascular disease 18 (94.4%), epilepsy 23 (82.6%), extrapyramidal disorders 8 (100%), dementia 12 (100%), headache 11 (63.6%), psychiatric disorders 11 (27.3%). In addition, SPECT was performed in 28 male volunteers during motor or visual imagery tasks and a significant increase (p = 0.035) of relative tracer deposition was observed in the left inferior occipital region during visual imagery when compared with motor imagery. The results indicate that [99mTc]HM-PAO SPECT is valuable for demonstrating pathologic and physiologic changes of the brain.

Topics: Adult; Aged; Basal Ganglia Diseases; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Dementia; Epilepsy; Female; Headache; Humans; Imagination; Male; Mental Disorders; Middle Aged; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

We have compared the regional distribution of 99Tcm-HMPAO with regional cerebral blood flow (rCBF). CBF was measured by single photon emission computerized tomography (SPECT) using a TOMOMATIC 64 after 133Xe inhalation in 41 patients. With the same SPECT device the distribution of 99Tcm-HMPAO was measured after i.v. injection. High resolution (HR) and low resolution (LR) studies were performed yielding a resolution of 6 to 10 mm (HR) and 15 to 20 (LR). 99Tcm-HMPAO images showed close resemblance to xenon-133 CBF tomograms. Only about 20% of the (decay corrected) brain counts were lost during the first 24 h post injection. A slight decrease in contrast was measured comparing side-to-side asymmetry ratios from the serial studies. This loss of contrast is mainly due to back-diffusion and clearance of a part of the 99Tcm-HMPAO complex from the brain. It could be corrected for by a linearization algorithm. The slight loss of contrast will not be of any importance for the clinical use of this tracer complex.

Topics: Brain; Brain Diseases; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Xenon Radioisotopes

Topics: Adult; Brain; Brain Diseases; Cerebrovascular Disorders; Epilepsy; Female; Headache; Humans; Middle Aged; Organometallic Compounds; Oximes; Reference Values; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adolescent; Adult; Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Aged; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Female; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Pure sensory stroke (PSS) is typically caused by a lacunar infarct located in the ventral-posterior (VP) thalamic nucleus contralateral to the paresthetic symptoms. The lesion is usually so small that it cannot be seen on computerized tomography (CT), as illustrated by our case. In our moderately hypertensive, 72-year-old patient with PSS, CT scanning and conventional nuclear magnetic resonance imaging (NMRI) scanning using a 7-mm-thick slice on a 1.5 Tesla instrument all failed to visualize the thalamic infarct. Using the high-resolution mode with 2-mm slice thickness it was, however, clearly seen. In addition, NMRI unexpectedly showed diffuse periventricular demyelinization as well as three other lacunar infarcts, i.e., findings characteristic of subcortical arteriosclerotic encephalopathy (SAE). This prompted psychometric testing, which revealed signs of mild (subclinical) dementia, in particular involving visiospatial apraxia; this pointed to decreased function of the right parietal cortex, which was structurally intact on CT and NMRI. Single photon emission computerized tomography by Xenon-133 injection and by hexamethyl-propyleneamine-oxim labeled with Technetium-99m showed asymmetric distribution of cerebral blood flow (CBF), with an 18% lower value in the right parietal cortex compared to the left side; this indicated asymmetric disconnection of the cortex by the SAE. Thus, the tomograms of the functional parameter, CBF, correlated better with the deficits revealed by neuropsychological testing than by CT or NMRI.

Topics: Aged; Brain; Brain Diseases; Cerebrovascular Circulation; Cerebrovascular Disorders; Dementia; Humans; Intracranial Arteriosclerosis; Magnetic Resonance Imaging; Male; Organometallic Compounds; Oximes; Syndrome; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Xenon Radioisotopes

A recently developed Tc-99m radiocompound, hexamethylpropyleneamine oxime (Tc-99m HM-PAO), exhibits favorable properties for regional cerebral blood flow study in man. The authors present a case of luxury perfusion syndrome observed in a 72-year-old patient with acute stroke and a right-sided hemiplegia, documented by planar scintigraphy and SPECT study in correlation with CT scan. The metabolic basis of this phenomenon is discussed and the usefulness of assessing regional brain perfusion by Tc-99m HM-PAO with conventional nuclear medicine equipment is underlined.

Topics: Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Male; Organometallic Compounds; Oximes; Radionuclide Imaging; Technetium; Technetium Tc 99m Exametazime

After having outlined the importance of evaluating, in cerebral diseases, the regional cerebral blood flow by means of a non invasive method, the advantages of SPECT with Tc99m HM-PAO compared to the SPECT with radioxenon and iodoamphetamine are point out. The results obtained with this method on 28 different patients, six of with were normal subjects, while the remaining 22 were suffering: six from cerebro vascular disease, four from epilepsy, three from TIA, six from dementia, two from depressive syndrome and one from hemicrania are reported. The comparison of the results with literature references, proves that the tracer employed is definitely superior to TCT, while there is a coincidence with SPECT data obtained with radioxenon and iodoamphetamine. The radiotracer employed can be successfully used, due to its convenient physical-chemical features, in a daily routine, for the evaluation of regional cerebral blood flow in encephalic diagnostics.

Topics: Adult; Aged; Brain Diseases; Cerebrovascular Disorders; Dementia; Depressive Disorder; Diagnosis, Differential; Epilepsy; Evaluation Studies as Topic; Humans; Middle Aged; Oximes; Reference Values; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

A new radiopharmaceutical, technetium-99m hexamethylpropyleneamine oxime (99mTc-d, 1-HM-PAO), has been reported to cross the blood-brain-barrier and to distribute in brain in proportion to regional blood flow. This study reports brain imaging obtained with 99mTc-d,1 HM-PAO in 20 subjects; seven without evidence of cerebral disease and 13 with cerebrovascular disorders. In 16 patients comparative data were available with N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamine ([123I]HIPDM). Technetium-99m-d, 1-HM-PAO is retained sufficiently long to allow single photon emission computed tomography (SPECT) with widely available rotating gamma camera systems. The kinetics demonstrated a rapid brain uptake and prolonged retention of activity in cerebral structures. Good tomographic images are obtained with much higher uptake in gray than in white matter. Blood flow maps are comparable to those achieved with [123I]HIPDM and established strokes were clearly seen, with similar details as in HIPDM studies. Delayed studies showed that the distribution in the brain remained virtually unchanged. Technetium-99m-d, 1-HM-PAO imaging appears particularly promising in routine examination of patients with cerebrovascular disorders.

Topics: Brain; Cerebrovascular Disorders; Evaluation Studies as Topic; Humans; Iodobenzenes; Ischemic Attack, Transient; Oximes; Regional Blood Flow; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Blood Volume; Brain; Cerebrovascular Disorders; Humans; Oximes; Regional Blood Flow; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Male; Oximes; Radionuclide Imaging; Technetium; Technetium Tc 99m Exametazime

The first clinical data is given on 99Tcm-hexamethylpropyleneamine oxime (HM-PAO) in normal subjects and patients with established stroke. Regional cerebral blood flow maps (rCBF) have been recorded and displayed in tomographic mode with this new radiopharmaceutical. Good images were obtained, comparable to those achieved with 123I-isopropylamphetamine (IMP).

Topics: Amphetamines; Brain; Cerebral Infarction; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Iodine Radioisotopes; Iofetamine; Oximes; Radiation Dosage; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed