technetium-tc-99m-exametazime and Cerebral-Infarction

Radiotracers called chemical microsphere are widely accepted as brain perfusion agents. Following the intravenous administration, these drugs are transported via the artery to the brain, cross the intact blood-brain barrier, and enter the brain tissue. Once the tracer flows into the brain, the efflux of the tracer is prevented by some trapping mechanism, resulting in prolonged retention. Because the distribution of the accumulated tracer remains approximately consistent with regional cerebral blood flow for a relatively long period, high-quality SPECT images reflecting the distribution pattern of cerebral blood flow can be acquired. However, unlike true microsphere, cerebral kinetics of the brain perfusion agents is complicated, and various causes may produce discrepancy between the distributions of the tracer and blood flow. In this review, cerebral kinetics of the brain perfusion agents used commonly is discussed. The knowledge of the mechanism of brain accumulation appears to be essential to appropriately determine the tracer of choice and interpret the obtained images.

Topics: Amphetamines; Brain; Brain Neoplasms; Cerebral Infarction; Cerebrovascular Circulation; Cysteine; Humans; Iodine Radioisotopes; Iofetamine; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime

Topics: Adult; Aged; Astrocytoma; Brain; Brain Diseases; Brain Neoplasms; Cerebral Infarction; Electroencephalography; Female; Humans; Magnetic Resonance Spectroscopy; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Left-sided hemichorea developed suddenly in a 73-year-old male. Computed tomography revealed a left subdural hematoma (SDH) and infarction in the right corona radiata and temporo-occipital region. Hemichorea subsided completely after removal of the SDH. Postoperative single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime revealed a global low-perfusion area in the right cerebral hemisphere. Right carotid angiography demonstrated severe stenosis of the trunk of the right middle cerebral artery. The cerebral blood flow in the right cerebral hemisphere had probably already decreased to nearly the critical level and was reduced further by the left SDH, inducing the left-sided hemichorea due to dysfunction of the right cerebral hemisphere. This case shows that when hemichorea ipsilateral to a SDH is present, it is important to ascertain whether there is a pre-existing ischemic lesion in the contralateral cerebral hemisphere, particularly in the basal ganglia, thalamus, or corona radiata.

Topics: Aged; Cerebral Infarction; Chorea; Chronic Disease; Dominance, Cerebral; Hematoma, Subdural; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

This study evaluated blood flow and metabolite changes in cerebral diaschisis from internal capsule region infarction using regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT) and 1H magnetic resonance spectroscopic imaging (MRSI). We hypothesized that complementary measures of diaschisis effects in white matter (characterized by 1H MRSI) and gray matter (characterized by changes in rCBF) can be measured and exhibit parallel changes.. Five stroke patients and 16 normal controls underwent Tc-99m hexamethylpropyleneamine-oxime brain SPECT and 1H MRSI at 4.1 T. The metabolites N-acetyl aspartate (NAA) and creatine (Cr) were measured using 1H MRSI. The tissue content was expressed as the percent of gray or white matter in each MRSI voxel to allow comparison of the differential effects of diaschisis in gray and white matter tissue types. The blood flow and metabolite changes were evaluated at superior cerebral regions distant from the stroke to allow a measure of diaschisis relatively unconfounded by their expected changes in the infarction region.. The rCBF SPECT data in stroke patients showed a perfusion defect, with size ranging from 1.23 cc to 10.23 cc, in the region of cortical diaschisis. 1H MRSI showed increased Cr/NAA ratios in regions of white matter diaschisis. There was a tendency for larger rCBF defect size to be associated with greater increases in Cr/NAA values in the same diaschitic cerebral hemisphere, ipsilateral to the infarction.. Diaschisis ipsilateral to stroke in white matter can be characterized by 1H MRSI, and diaschisis ipsilateral to stroke in cortical gray matter regions can be characterized by changes in rCBF. The tendency for greater reductions in cortical rCBF values to be associated with increased Cr/NAA values in the same diaschitic cerebral hemisphere implies that a relationship exists between rCBF reductions in gray matter and abnormal changes in white matter subservient to it.

Topics: Adult; Aged; Aspartic Acid; Blood Flow Velocity; Brain; Cerebral Infarction; Cerebrovascular Circulation; Creatine; Female; Humans; Internal Capsule; Magnetic Resonance Spectroscopy; Male; Middle Aged; Paresis; Predictive Value of Tests; Reference Values; Stroke; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were studied in 75 patients with cerebral infarction. All patients were alert with the symptoms of hemiparesis and/or aphasia, and were divided into two groups: 42 patients had occlusion or stenosis of >75% at the internal carotid artery or main trunk of middle cerebral artery; and 33 patients did not. Hemispheric mean CBF was measured by performing first-pass radionuclide angiography using 99mTc-hexamethylpropylene amine oxime. CVR was measured as the percentage change from the baseline mean CBF value after the administration of 500 mg acetazolamide. The CVR in both groups was significantly impaired (5.2+/-6.3%, P<0.001 and 7.7+/-6.1%, P<0.01, respectively) compared with normal controls (14.7+/-3.3%), although the mean CBF was not significantly reduced compared with age-matched controls. In the 12 patients with unilateral carotid occlusion, five patients with good collateral flow via the anterior communicating artery showed preserved CVR (11.0+/-7.8%), but those without did not (1.6+/-7.0%). CVR is impaired in alert patients with cerebral infarction, although the mean CBF is not reduced, and good collateral flow via the anterior communicating artery in patients with carotid occlusion may be a sign of well-preserved haemodynamic status.

Topics: Acetazolamide; Adult; Aged; Aged, 80 and over; Carbonic Anhydrase Inhibitors; Carotid Stenosis; Cerebral Infarction; Cerebrovascular Circulation; Chronic Disease; Female; Humans; Male; Middle Aged; Radiopharmaceuticals; Stroke; Technetium Tc 99m Exametazime; Ventriculography, First-Pass

There is no routinely used method for imaging the location of the extent and severity of cerebral tissue perfusion changes during the first hours of ischemic stroke, the period during which therapeutic intervention is most likely to be successful. Cerebral perfusion measurements with single-photon emission CT (SPECT) may potentially provide this information rapidly and noninvasively. In this study, the sensitivity and specificity of 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT cerebral perfusion measurements during the first 48 hours of cerebral ischemia for the localization of cerebral infarction were determined.. One hundred and four patients with acute ischemic stroke underwent 99mTc-HMPAO SPECT and CT scanning during the first 48 hours. In each patient, the location of the SPECT perfusion abnormality was compared with the location of infarction on a second brain CT acquired at a mean of 8 days after stroke.. During the first 48 hours of ischemic stroke, the sensitivity of 99mTc-HMPAO SPECT in locating the site of infarction was 79% (110/139), and the specificity was 95% (362/381). SPECT was more sensitive in the localization of the vascular territory of cortical infarction (sensitivity, 93%) than pure subcortical infarcts (sensitivity, 47%). During the first 48 hours, SPECT was significantly more sensitive than brain CT (sensitivity of brain CT during the first 48 hours, 35%; P < .001, Mann-Whitney U test).. HMPAO SPECT measurement provides a widely available and practical technique of locating cerebral ischemia acutely and demonstrates high sensitivity and specificity within the first 48 hours for the localization of the vascular territory of cerebral infarction. It is most sensitive for cortical ischemia but is limited by its resolution in the subcortex, particularly of white matter perfusion changes.

Topics: Aged; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Organotechnetium Compounds; Oximes; Prospective Studies; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

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

A comparative interim analysis was performed of clinical parameters, computed tomographic (CT) scan results and technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (SPET) findings obtained within 12 h of acute supratentorial ischaemic infarction. First, the applicability for SPET semiquantification in this study of the "method of Mountz", simultaneously accounting for extent and degrees of hypoperfusion by expressing deficits as millilitre of zero perfusion, was considered. Next, the relative contributions of perfusion SPET and CT scan in the acute stage of ischaemic infarction were compared in 27 patients (mean age 68.8 years). Finally, the correlation of SPET lesions with clinical parameters at onset was evaluated. The method of Mountz represents a workable, accurate virtual parameter, with the assumption that the contralateral brain region remains uninvolved. Interobserver reproducibility in 12 SPET studies, with lesions varying between 6 and 369 cc, showed a correlation coefficient r of 0.99. In practice, because of inconstant distribution of activities in the brain, the method can only be applied slice by slice and not on the total global volume. While the mean delay since the onset of symptomatology was approximately 7 h for both SPET and CT scan, SPET showed lesions concordant with the clinical neurological findings in 100% and CT scan in only 48%. One could hypothesize that SPET examinations performed later would show larger functional defects, because of the development of additional functional changes secondary to biochemical alterations. However, in this regard no statistically significant differences were found between two subproups, taking the median of delay before SPET examination as cut-off.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Cerebral Infarction; Cerebrovascular Circulation; Double-Blind Method; Female; Humans; Male; Organotechnetium Compounds; Oximes; Piracetam; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

We report a 65-year-old man with a right cerebral infarction that occurred 15 years ago and a residual left hemiparesis that began with progressive contralateral hemiparesis. During the hospitalization, the patient developed a bilateral alien hand syndrome. Urgent CT, MR, CT angiography, and brain perfusion SPECT were performed that revealed an old right cerebral infarction and a new ischemic lesion in left parietal lobe and adjacent brain territories.

Topics: Aged; Alien Limb Phenomenon; Cerebral Angiography; Cerebral Infarction; Humans; Magnetic Resonance Imaging; Male; Multimodal Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We report a 66-year-old ambidextrous man who suddenly developed aphasia seven days after coronary artery bypass grafting surgery. CT scan performed 30 minutes after onset failed to depict acute ischemic lesion. MR imaging could not be performed because of intrathoracic wires. An emergent angiogram demonstrated filling defect in the right precentral artery territory. Transaxial images of 99mTc-HMPAO SPECT showed hypoperfusion areas in the right frontal and left temporo-parietal regions. Using the three-dimensional stereotactic surface projections (3D-SSP) of 99mTc-HMPAO SPECT, we could clearly detect a sharply demarcated ischemic area which was later confirmed to be an infracted lesion in the follow-up CT. 3D-SSP, thus, appears to be useful for identifying acute infarction in such cases that MRI is impermissible.

Topics: Acute Disease; Aged; Brain; Cerebral Infarction; Humans; Imaging, Three-Dimensional; Male; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To evaluate the feasibility of utilizing cerebral blood flow (CBF) index images, we attempted to investigate 1) whether CBF index images can reveal the resulting infracted area, 2) whether the CBF index can correlate other modality (SPECT).. DWI and DPI were obtained in 17 patients within 12 hours of stroke onset and follow up MRI. On three DPI delivered images, namely relative regional cerebral blood volume (rrCBV), uncorrected mean transit time (MTTu) and CBF index images, correlations between initial lesion volume of and follow up infarction volume of three images and rCBF images delivered with singular value decomposition (SVD) methods were assessed. Then 99mTc-ECD SPECT was taken immediately after MRI to correlate to MRI data.. Among the three images, lesion volume of CBF index images against follow up infarct volume had the highest correlation (r = 0.995) to a linear fit and the slope was closest to 1.0 (0.91) and had identical accuracy to the regression coefficient of rCBF images. CBF index well correlated to SPECT delivered CBF.. CBF index images can accurately predict final infarct volume. Evaluating CBF index images together with DWI can guide the initial assessment in the acute stage of cerebral ischemia.

Topics: Acute Disease; Brain; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; Diffusion Magnetic Resonance Imaging; Echo-Planar Imaging; Humans; Magnetic Resonance Angiography; Prognosis; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Carbon-11-L-methyl-methionine (11C-methionine) has been reported to be useful for evaluating brain tumors, but several other brain disorders have also shown signs of high methionine uptake. We retrospectively evaluated the significance of 11C-methionine uptake in cerebrovascular diseases, and also compared our results with those for 18F-FDG PET and 99mTc-HMPAO SPECT.. Seven patients, including 3 patients with a cerebral hematoma and 4 patients with a cerebral infarction, were examined. All 7 patients underwent both 11C-methionine PET and 99mTc-HMPAO SPECT, and 6 of them underwent 18F-FDG PET.. A high 11C-methionine uptake was observed in all 3 patients with cerebral hematoma. Increased 99mTc-HMPAO uptake was observed in 2 out of 3 patients, and all 3 patients had decreased 18F-FDG uptake. Of 4 patients with a cerebral infarction, high 11C-methionine uptake was observed in 3. Increased 99mTc-HMPAO uptake was also observed in one patient, whereas 3 patients had decreased 18F-FDG uptake.. We should keep in mind that high 11C-methionine uptake is frequently observed in cerebrovascular diseases. CVD should therefore be included in the differential diagnosis when encounting patients with a high 11C-methionine uptake.

Topics: Adolescent; Adult; Aged; Cerebral Hemorrhage; Cerebral Infarction; Female; Fluorodeoxyglucose F18; Hematoma; Humans; Male; Methionine; Middle Aged; Radiopharmaceuticals; Retrospective Studies; Technetium Tc 99m Exametazime; Tissue Distribution; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Cerebral Infarction; Chronic Disease; Heart Ventricles; Humans; Incidental Findings; Magnetic Resonance Imaging; Male; Middle Aged; Persistent Vegetative State; Radiography; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Thrombosis; Ventricular Dysfunction, Left

The brain distribution of 9mTc-hexamethylpropyleneamine oxime (HMPAO) correlates with regional brain perfusion, whereas 99mTc-ethyl cysteinate dimer (ECD) reflects not only perfusion but also the metabolic status of brain tissue. We compared 99mTc-ECD single-photon emission CT (SPECT) with 99mTc-HMPAO SPECT early after recanalization by local intraarterial thrombolysis (LIT) in patients with acute embolic middle cerebral artery occlusion. We also assessed the predictive value of 99mTc-HMPAO and 99mTc-ECD SPECT for the development of ischemic brain damage.. 99mTc-HMPAO and consecutive 99mTc-ECD SPECT studies were performed in 15 patients within 3 hours of LIT. The two SPECT studies were obtained independently using a subtraction technique. SPECT evaluation was performed using semiquantitative region-of-interest analysis. Noninfarction, infarction, and hemorrhage were identified by follow-up CT or MR imaging.. Forty-five lesions were identified (21 noninfarctions, 19 infarctions, and five hemorrhages). Regardless of 99mTc-HMPAO SPECT findings, lesions showing isoactivity (count rate densities of 0.9 to 1.1 as compared with the contralateral side) on 99mTc-ECD SPECT were salvaged. Lesions with hypoactivity (values < 0.9) on 99mTc-ECD SPECT developed irreversible brain damage. Hemorrhage appeared in lesions with both hyperactivity (values > 1.1) on 99mTc-HMPAO SPECT and hypoactivity on 99mTc-ECD SPECT.. The brain distribution of 99mTc-ECD in a reperfused area identified by 99mTc-HMPAO SPECT early after recanalization of acute ischemic stroke is dependent on cerebral tissue viability. By combining 99mTc-ECD and 99mTc-HMPAO SPECT, performed within the first few hours of LIT, it is possible to identify patients at risk for hemorrhagic transformation reliably.

Topics: Aged; Arterial Occlusive Diseases; Brain; Cerebral Hemorrhage; Cerebral Infarction; Cysteine; Female; Fibrinolytic Agents; Humans; Injections, Intra-Arterial; Intracranial Embolism; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Predictive Value of Tests; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Cognitive dysfunction is found in a considerable proportion of patients with systemic lupus erythematosus (SLE). SPECT provides an estimate of regional cerebral blood flow (rCBF) which has been claimed to be sensitive to detect brain involvement in SLE. It is, however, uncertain if these perfusion defects are related to cognitive dysfunction. In the present study we investigated whether cerebral dysfunction assessed by neuropsychological measures was associated with changes in rCBE Fifty-two SLE patients were examined with a battery of neuropsychological tests and MRI of the brain. For each patient 99mTC-HMPAO-SPECT was performed with the visual cortex as reference, and a reduction in rCBF of > 15% was considered abnormal. Regional CBF was performed with an automated computer program quantitatively estimating blood perfusion in 16 symmetrical sectors of the brain. Several sectors of the brain showed varying areas of reduced rCBF with the temporal lobes most frequently involved. There were generally no associations between cognitive level of functioning and reduced rCBF. MRI demonstrated cerebral infarcts in 9 (17%) patients. In general rCBF was reduced in all sectors of the brain in patients with infarcts, although statistical significant difference in rCBF between patients with and without infarcts was only seen in the parietal lobe. Several neuropsychological functions were influenced by the presence of cerebral infarcts. There was no significant association between immunological measures and SPECT findings or neuropsychological measures. Neuropsychological dysfunction in SLE was associated with the presence of cerebral infarcts detected by MRI, but not by changes in rCBF. SPECT seems to add little if any information to that obtained by clinical examination, neuropsychological testing, and MRI. Since anticoagulation may prevent cerebral infarcts, such prophylactic intervention may be of importance in preventing cognitive deterioration.

Topics: Adult; Anticoagulants; Cerebral Cortex; Cerebral Infarction; Cognition Disorders; Female; Humans; Lupus Erythematosus, Systemic; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Radiopharmaceuticals; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cerebral perfusion single photon emission computed tomography (SPECT) has been used to confirm the localization of the epileptic focus and the evaluation of seizure. Recently, diffusion-weighted MR imaging (DWI) has been recognized for evaluation of seizure activity. We describe a case of transient seizure activity demonstrated by Tc-99m HMPAO SPECT and DWI. This patient was a 61-year-old woman with a 10-month history of right middle cerebral artery (MCA) infarction who had a generalized seizure during MRI. DWI immediately after seizure showed transient hyperintensity in the right frontal gray matter and the white matter, and these apparent diffusion coefficients (ADC) were transiently decreased. This transient hyperintensity on DWI corresponded to transient hyperperfusion identifying the epileptic focus on interictal Tc-99m HMPAO SPECT. Transient sustained seizure activity might cause these changes on DWI and SPECT. It was considered that interictal Tc-99m HMPAO SPECT showed the delayed hyperperfusion caused by excitatory neuronal overaction and DWI showed cytotoxic edema seizure-induced by energy failure of the membrane-bound Na/K-ATPase pump.

Topics: Cerebral Infarction; Female; Humans; Magnetic Resonance Imaging; Middle Aged; Paresis; Radiopharmaceuticals; Seizures; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cerebral blood flow (CBF) and cerebral autoregulation have been investigated 24 h after transient focal ischaemia in the rat. Cerebral blood flow was measured autoradiographically before and during a moderate hypotensive challenge, to test autoregulatory responses, using two CBF tracers, (99m)Tc-d,l-hexamethylproyleneamine oxide and 14C-iodoantipyrine. Prior to induced hypotension, CBF was significantly reduced within areas of infarction; cortex (28 +/- 20 compared with 109 +/- 23 mL/100 g/min contralateral to ischaemic focus, P = 0.001) and caudate (57 +/- 31 compared with 141 +/- 32 mL/100 g/min contralaterally, P = 0.005). The hypotensive challenge (mean arterial pressure reduced to 60 mmHg by increasing halothane concentration) did not compromise grey matter autoregulation in the contralateral hemisphere; CBF data were not significantly different at normotension and during hypotension. However, in the ipsilateral hemisphere, a significant volume of cortex adjacent to the infarct, which exhibited normal flow at normotension, became oligaemic during the hypotensive challenge (e.g. frontal parietal cortex 109 +/- 15% to 65 +/- 15% of cerebellar flow, P < 0.01). This resulted in a 2.5-fold increase in the volume of cortex which fell below 50% cerebellar flow (39 +/- 34 to 97 +/- 46 mm3, P = 0.003). Moderate hypotension induced a significant reduction in CBF in both ipsilateral and contralateral subcortical white matter (P < 0.01). In peri-infarct caudate tissue, CBF was not significantly affected by hypotension. In conclusion, a significant volume of histologically normal cortex within the middle cerebral artery territory was found to have essentially normal levels of CBF but impaired autoregulatory function at 24 h post-ischaemia.

Topics: Animals; Antipyrine; Blood Pressure; Brain; Carbon Radioisotopes; Cerebellum; Cerebral Cortex; Cerebral Infarction; Cerebrovascular Circulation; Homeostasis; Ischemic Attack, Transient; Male; Rats; Rats, Inbred F344; Regional Blood Flow; Technetium Tc 99m Exametazime; Time Factors

Topics: Brain; Cerebral Infarction; Cerebrovascular Circulation; Diagnosis, Differential; Hemianopsia; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The authors describe a patient in whom neuroimaging using Tc-99m HMPAO SPECT, F-18 fluorodeoxyglucose (F-18 FDG) coincidence imaging, and magnetic resonance imaging (MRI) identified an anterior choroidal artery infarction. Neuroimaging played a critical role in confirming this diagnosis, because the patient had symptoms of progressive cognitive decline and satisfied the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD).. Tc-99m HMPAO brain SPECT was performed using a triple-head gamma camera. F-18 FDG scanning was obtained 40 minutes after intravenous injection of 5 mCi F-18 FDG using a coincidence camera. A brain MRI scan was performed using a 1.5-Tesla scanner.. Tc-99m HMPAO SPECT showed focal hypoperfusion to the right parahippocampal cortex. F-18 FDG coincidence imaging showed a more extensive reduction in glucose metabolism compared with SPECT. The MRI scan confirmed the presence of a small segmental choroidal artery infarction. The Tc-99m HMPAO and F-18 FDG scans were not consistent with AD.. This case illustrates the value of the regional cerebral blood flow SPECT for evaluating memory impairment in the elderly. Decreased regional cerebral blood flow to the posterior temporoparietal region is consistent with AD, whereas regional cerebral blood flow diminution in a vascular territory is consistent with vascular dementia. In this case, the patient was clinically diagnosed with AD, and SPECT was performed to establish the baseline regional cerebral blood flow before the cholinesterase inhibitor donepezil was administered. An infarction was diagnosed on the regional cerebral blood flow brain SPECT scan, which was later confirmed by MRI. Infarctions of the parahippocampal cortex may resuft in memory impairment, which can appear clinically similar to AD.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Brain; Cerebral Infarction; Cerebrovascular Circulation; Cognition Disorders; Diagnosis, Differential; Female; Fluorodeoxyglucose F18; Humans; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The relationship between hypofixation and hyperfixation of 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) remains unclear. The purpose of this study was to compare 99mTc-HMPAO SPECT with regional cerebral blood flow (CBF) imaging using 133Xe inhalation in patients with subacute cerebral infarction and to investigate the behavior of 99mTc-HMPAO in the infarct area using dynamic SPECT.. 133Xe and consecutive 99mTC-HMPAO SPECT studies, the latter of which consisted of dynamic and static scanning, were performed on 51 patients (22 women, 29 men; age range, 40-83 y; mean age, 61 y) with cortical infarction in the middle cerebral artery territory 13-15 d after stroke onset. One region of interest (ROI) was drawn in the infarct area. The control ROI was mirrored to the contralateral side, and the same set of ROIs was applied to all SPECT studies. Fractional fixation of 99mTc-HMPAO in the infarct area was evaluated relatively as the ratio of the infarct-to-control region in 99mTc-HMPAO static tomograms/the ratio of the infarct-to-control region in CBF images using 133Xe inhalation and was classified as hyperfixation when this value was >1.1 and hypofixation when this value was <0.9. To investigate the behavior of 99mTc-HMPAO in the infarct area, the second (36-72 s after tracer injection) and eighth (252-288 s after tracer injection) of 8 dynamic scans were selected, and the washout rate was calculated using the formula: 1 - (mean count in the eighth scan/mean count in the second scan).. The infarct area showed hyperfixation of 99mTc-HMPAO when CBF in the area was 35 mL/100 g/min or less and showed hypofixation when CBF was >45 mL/U100 g/min. The washout rate was usually negative when CBF imaging using 133Xe inhalation was <20 mL/100 g/min but was positive when it was >45 mUL/100 g/min. The washout rate was negative when the infarct area showed hyperfixation of 99mTc-HMPAO but was positive when it showed hypofixation.. 99mTc-HMPAO SPECT underestimates CBF in high-flow regions and overestimates CBF in low-flow regions of subacute cerebral infarction. 99mTc-HMPAO hypofixation and hyperfixation are associated with backdiffusion from the brain to blood and gradual accumulation of hydrophilic metabolites, respectively. Dynamic images should be useful for discriminating between 99mTc-HMPAO hypofixation and hyperfixation.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon Radioisotopes

Loss of psychic self-activation has been described after bilateral lesions to the globus pallidus, striatum, and white matter of the frontal lobes, but it is a very rare sign of bithalamic lesions. The exact functional-anatomic mechanism underlying loss of psychic self-activation following bithalamic lesions remains to be elucidated.. We present clinical, neuropsychological, structural, and functional neuroimaging data of an 18-month follow-up period of a man with prominent loss of psychic self-activation after coronary arteriography. Except for memory decline, accompanying symptoms remained restricted to the acute phase. The neurobehavioral syndrome consisted mainly of apathy, indifference, poor motivation, and flattened affect, and this remained unchanged during the entire follow-up period. MRI showed a bithalamic infarction involving the nucleus medialis thalami bilaterally. Single-photon emission CT revealed a severe relative hypoperfusion of both thalami, a relative hypoperfusion of both nuclei caudati, and a relative hypoperfusion mesiofrontally.. Single-photon emission CT data support the hypothesis that the neurobehavioral manifestations after bithalamic paramedian infarction are caused by disruption of the striatal-ventral pallidal-thalamic-frontomesial limbic loop. Probably, bilateral disruption at different levels of the striatal-ventral pallidal-thalamic-frontomesial loop may lead to a similar clinical picture consisting of loss of psychic self-activation.

Topics: Affect; Amnesia; Arousal; Awareness; Cerebral Infarction; Functional Laterality; Humans; Intelligence Tests; Male; Middle Aged; Motivation; Radiopharmaceuticals; Self Concept; Stroke; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon

Though diffusion-weighted images (DWI) have been increasingly used to detect super-acute-phase cerebral infarction in recent years, they have primarily been obtained through the use of high magnetic machines of more than 1.5T. In this study, we discussed the usefulness of DWI obtained using 0.5T MRI in comparison with CT, MRI (FLAIR and T2 weighted image) and SPECT (99mTc-HMPAO). DWI were able to detect ischemic lesions earlier than FLAIR or T2-weighted images. Scanning time was short at four seconds for eight slices, and the quality of image was sufficient for clinical usage. The most available b-value seems to be 800. There were less susceptibility artifacts in the 0.5T DWI than in the 1.5T DWI. From these data, we presume that it is possible to detect super-acute-phase cerebral ischemia on the 0.5T DWI, proving the clinical usefulness of DWI. Furthermore, DWI is considered useful in observing chronological changes in cerebral infarction, differentiation of abscess or brain tumor, diagnosis of moyamoya disease, degenerative disease and so on.

Topics: Acute-Phase Reaction; Aged; Aged, 80 and over; Brain; Cerebral Infarction; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

The aim of this study was to correlate the abnormality in cerebral blood volume (CBV) measured by dynamic susceptibility contrast-enhanced MRI with that in cerebral blood flow (CBF) estimated by single-photon emission CT with [99mTc]hexamethylpropylenamine-oxime in patients with acute ischemic stroke.. Nine patients with unilateral occlusion of either the middle cerebral artery or the internal carotid artery (4 men and 5 women; mean+/-SD age, 74.4+/-11.6 years) were studied within 6 hours after stroke onset. The relative CBV (relCBV) and CBF (relCBF) in the lesions were defined relative to the contralateral mirror regions.. In the brain regions with mild (relCBF >/=0.60), moderate (0.401.0) regions was significantly lower than that for hypovolemic (relCBV <1.0) regions in the relCBF range between 0.40 and 0.50 (P<0.02).. In acute ischemic stroke within 6 hours of onset the CBV can be either increased, normal, or decreased, depending on the severity of hypoperfusion. The increased CBV has a protective effect on evolving infarction. Although the CBF is a better predictor of tissue outcome, the CBV measurement may help detect potentially salvageable brain tissue in the penumbra with compromised blood flow.

Topics: Acute Disease; Aged; Aged, 80 and over; Arterial Occlusive Diseases; Blood Volume; Cerebral Angiography; Cerebral Infarction; Cerebrovascular Circulation; Contrast Media; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Multivariate Analysis; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Quantification of metabolite concentrations by proton magnetic resonance spectroscopy (1H-MRS) in the human brain using water as an internal standard is based on the assumption that water content does not change significantly in pathologic brain tissue. To test this, we used 1H-MRS to estimate brain water content during the course of cerebral infarction. Measurements were performed serially in the acute, subacute, and chronic phase of infarction. Fourteen patients with acute cerebral infarction were examined as well as 9 healthy controls. To correlate with regional cerebral blood flow (rCBF) SPECT-scanning using 99mTc-HMPAO as flow tracer was performed in the patients. Mean water content (SD) in the infarct area was 37.7 (5.1); 41.8 (4.8); 35.2 (5.4); and 39.3 (5.1) mol x [kg wet weight](-1) at 0-3; 4-7; 8-21; and >180 days after stroke, respectively. Water content increased between Day 0-3 and Day 4-7 (p = 0.034) and decreased from Day 0-3 to Day 8-21 (p = 0.028). Water content at Day 4-7 was significantly higher than in controls (p < or = 0.05). At the same time intervals, mean rCBF (SD) was 76 (23); 94 (31); 106 (35); and 64 (26)%, respectively. There was a significant increase in rCBF from Day 0-3 to Day 4-7 (p = 0.050) and from Day 0-3 to Day 8-21 (p = 0.028). No correlation between rCBF and water content was found. Water content in ischemic brain tissue increased significantly between Day 4-7 after stroke. This should be considered when performing quantitative 1H-MRS using water as an internal standard in stroke patients.

Topics: Acute Disease; Aged; Body Water; Brain; Brain Chemistry; Case-Control Studies; Cerebral Infarction; Cerebrovascular Circulation; Humans; Magnetic Resonance Spectroscopy; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Time Factors

The aim of this study was to evaluate regional and remote diaschisis of inferior brain stem or cerebellar infarcts in 25 patients presenting with relatively limited lesions. Patients presented with medullary, pontine or cerebellar infarction.. Lesions were evaluated on MRI (0.5 T). Regional cerebral blood flow (rCBF) was assessed by means of SPECT, after injection of 9rmTc-hexamethyl propyleneamine oxime (HMPAO) and, when possible, inhalation of 133Xe in the same session. For each method, asymmetry indices (Als), comparing contralateral to ipsilateral rCBF values, were calculated in four areas of each cerebral hemisphere and in the cerebellum and later compared with values obtained in healthy subjects (P = 0.05).. Higher rCBF values were observed in the contralateral cerebellum in 2 of 7 patients with selective lateral medullary lesions, and cerebellar Als were significantly increased. When a cerebellar infarct was associated with a lateral medullary lesion, the cerebellar and contralateral hemispheric asymmetries were more severe. Unilateral paramedian pontine infarcts had more frequent consequences on the cerebellum (2 of 3 cases), with rCBF or tracer uptake being reduced in the ipsilateral or the contralateral lobe. Inverse cerebral hemispheric asymmetry could then be observed. Bilateral pontine lesions were difficult to evaluate. Using 99mTc-HMPAO, discrete cerebellar asymmetry was observed in 3 of 6 cases. Pure cerebellar infarcts in the posterior inferior cerebellar artery territory were always associated with a severe ipsilateral flow drop in the cerebellum, and contralateral hemispheric diaschisis was frequent (3 of 4 patients), predominating in the frontotemporal cortex and subcortical structures. This was also more obvious using 99mTC-HMPAO than 133Xe. Variance analysis showed that hemispheric diaschisis was more severe in mixed brain stem and cerebellar infarcts than in pure cerebellar or brain stem lesions. Furthermore, cerebellar and hemispheric AI values were not correlated with measurements of clinical deficits, disability or handicap.. Unilateral and limited inferior brain stem lesions can have ipsi- or contralateral consequences on the cerebellum and cerebral hemispheres rCBF. These remote effects are related to lesions of the main pathways joining these structures, resulting in deactivation and, in some cases, overactivation. Contrary to what has been suggested, consequences on cerebral hemispheres are more severe in mixed cerebellar and brain stem infarcts than in pure cerebellar lesions.

Topics: Adult; Cerebellar Diseases; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Medulla Oblongata; Middle Aged; Pons; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon Radioisotopes

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

Topics: Cerebral Infarction; Cerebrovascular Circulation; Humans; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Cerebral Infarction; Cerebrovascular Circulation; Humans; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Perfusion defects can be demonstrated reliably at an early stage with regional cerebral blood flow studies using SPECT. The administration of thrombolytic therapy in ischemic stroke is targeted at restoring cerebral perfusion immediately, leading to salvage of ischemic penumbra, smaller infarct size, and improved clinical outcome. This study considered the role of brain perfusion SPECT in the evaluation of reperfusion and brain function recovery of the infarcted area after early recanalization (less than 6 hours) of the occluded artery using intracarotid arterial urokinase therapy (ICAU).. Intracranial artery occlusion was confirmed in seven patients using emergency carotid angiography performed within the initial 6-hour period. Intracarotid arterial urokinase (500,000 to 800,000 units) was administered into the occluded arterial system (the left middle cerebral artery in four and the right middle cerebral artery in three patients). CT scanning was performed when the patients arrived in the emergency department and was repeated 24 to 48 hours after ICAU and at 7 days or earlier if clinically indicated. All patients had two SPECT studies, the first before urokinase administration and the second 24 or 48 hours later.. Complete recanalization of the occluded vessels was seen in one patient after ICAU, effective partial recanalization was achieved in four patients, and minimal recanalization occurred in the other two. Before ICAU, Tc-99m HMPAO brain SPECT showed decreased uptake of the infarcted area in all patients, whereas the follow-up brain SPECT performed 24 or 48 hours after ICAU revealed improvement in the uptake of the recanalized area on qualitative and semiquantitative assessments using an asymmetry index, suggestive of brain function recovery and clinical improvement. Hemorrhagic transformation adjacent to the reperfused regions occurred in two patients with partial recanalization of the left middle cerebral artery.. Reperfusion of the recanalized area and brain function recovery could be achieved if the occluded artery is recanalized within the initial 6-hour period using ICAU, and this was documented using brain perfusion SPECT without a delay in the therapeutic time window. Because the number of patients we studied was limited, further study is necessary to evaluate the effect of ICAU and to determine its prognostic significance.

Topics: Acute Disease; Adult; Aged; Brain; Carotid Arteries; Cerebral Angiography; Cerebral Arteries; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Injections, Intra-Arterial; Male; Middle Aged; Plasminogen Activators; Radiopharmaceuticals; Recovery of Function; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Urokinase-Type Plasminogen Activator

Topics: Brain; Brain Diseases; Carotid Artery Thrombosis; Carotid Artery, Internal; Cerebellar Diseases; Cerebral Infarction; Child; Female; Heart Septal Defects; Humans; Radiopharmaceuticals; Spleen; Syndrome; Technetium Tc 99m Aggregated Albumin; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Whole-Body Counting

Little is known about the effect of spontaneous reperfusion of human cerebral infarcts. Single photon emission computerised tomography (SPECT) data were analysed from a study using 99Tc(m) HMPAO (99Tc(m) hexamethylpropyleneamine oxime) in human cerebral infarction for the frequency of reperfusion and to see if it affected infarct size, oedema, haemorrhagic transformation, or functional outcome.. Fifty sequential cases of ischaemic stroke were studied with 124 99Tc(m) HMPAO SPECT at around one day, one week, and three months after stroke along with detailed clinical and functional assessments.. Visually apparent reperfusion occurred in 14 of 50 patients (28%) with a mean delay of 5.8 days and reperfusion was seen in seven others in whom it was identified on the basis of changes in perfusion deficit volume. It occurred in 13 of 23 embolic events but only in three of 23 other events. In only two cases did spontaneous reperfusion occur early enough to preserve tissue or function. Reperfusion did not otherwise reduce infarct size, or improve clinical or functional outcome, and was not associated with oedema but an association with haemorrhagic transformation was suggested. Reperfusion significantly decreased the apparent perfusion defect as measured by SPECT one week from the ictus, but was mostly non-nutritional and transient. The mean volume of tissue preserved by nutritional reperfusion was 10 cm3, but this was unequally distributed between cases. Late washout of 99Tc(m) HMPAO from areas of hyperaemic reperfusion may be a good prognostic marker but is a rare phenomenon and too insensitive to be of general applicability.. Spontaneous reperfusion after cerebral infarction occurs in 42% of cases within the first week but is associated with clinical improvement in only 2%. It has few adverse consequences although it may be associated with haemorrhagic transformation.

Topics: Activities of Daily Living; Adult; Aged; Aged, 80 and over; Brain; Cerebral Infarction; Female; Humans; Hyperemia; Male; Middle Aged; Prognosis; Prospective Studies; Radiopharmaceuticals; Reperfusion Injury; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Cerebral microangiopathy, indicated in MRI by lacunar infarctions (LIs) and deep white matter lesions (DWMLs), is said to be accompanied by vascular dementia, which is reportedly caused by LI and DWML.. To confirm this assumption, 57 patients with cerebral microangiopathy were assessed for changes in regional cerebral blood flow (rCBF) and glucose utilization (rMRGlu) in both white matter and cortex, and these findings were correlated to the results of extensive neuropsychological testing (cognitive, mnestic and attentiveness tests), as well as to MRI findings. A special head holder ensured reproducibility of positioning during measurement of rCBF (99mTc-HMPAO SPECT) and rMRGlu (18F-FDG PET) and MRI. White matter and cortex were quantified with regions of interest defined on MRI and superimposed to corresponding PET/SPECT slices. The rMRGlu was calculated according to Sokoloff, and rCBF was determined from normalization to the cerebellum. LI and DWML were graded by number and extent. Brain atrophy was classified as no to slight inner and/or outer atrophy (Group A) or moderate-to-severe inner and outer atrophy (Group B).. Even in severe DWMLs and in multiple LIs, rCBFs and rMRGlu values were not reduced. Analysis of variance identified atrophy and neuropsychological deficits as the main determinants for reduced rCBF and rMRGlu values (p < 0.05). However, 60% of patients (19 of 31) with neuropsychological deficits in attentiveness tests and 61% of patients (23 of 38) with mnestic deficits belonged to Group A and revealed decreased rCBF and rMRGlu values. Neuropsychological deficits correlated well with decreased rCBF and rMRGlu, whereas MRI patterns, such as LI and DWML, did not.. We conclude that LI and DWML are epiphenomena that morphologically characterize cerebral microangiopathy. Dementia or neuropsychological deficits, however, are exclusively reflected by functional criteria (rCBF and rMRGlu), as long as cerebral atrophy does not occur.

Topics: Aged; Brain; Cerebral Infarction; Cerebrovascular Circulation; Cohort Studies; Dementia, Vascular; Female; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Glucose; Humans; Magnetic Resonance Imaging; Male; Neuropsychological Tests; Radiopharmaceuticals; Reproducibility of Results; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Previous studies have shown the usefulness of divalent cobalt isotopes to visualize cerebral damage after stroke. The site of accumulation of cobalt ion is unknown but may be explained by neuronal influx, analogous to that of calcium ion. Additionally, uptake may be due to infiltrating leukocytes or protein-bound cobalt. The aims of this study were to compare 57Co-SPECT with leukocyte SPECT and to compare the SPECT findings with clinical outcome as scored by the Orgogozo scale.. Ten patients with a CT scan positive for middle cerebral artery infarcts were included in the study (7 men, 3 women; mean age 70 yr). Technetium-99m leukocyte and cobalt-SPECT (interval 2-4 days) were made with a double-headed gamma camera, after the injection of 10-15 mCi 99mTc-HMPAO-labeled leukocytes and 0.4 mCi 57Co, respectively. Scans were performed within 5-30 days after onset of the first symptoms. Regions of interest (ROI) containing the area of infarction in the slices displaying enhanced radioactivity or the middle cerebral artery (MCA) region in four successive slices were defined for calculating enhancement ratios. The 99mTc leukocyte enhancement ratio (LER) and cobalt enhancement ratio (CER) were defined as the quotient of radioactivity in the ROI and an identical contralateral ROI. The MCA stroke-scale according to Orgogozo was used to assess neurological deficits at the time of scanning and discharge.. Cobalt-57 and 99mTc-HMPAO showed uptake in the infarcted brain area in five patients; the quantitative uptake in the infarcted brain area of the two tracers correlated significantly (p < 0.05). Both the LER and the CER correlated significantly (p < 0.05) with the Orgogozo score at the time of scanning. Only the LER correlated significantly (p < 0.05) with the Orgogozo score at discharge.. Uptake of cobalt and leukocytes in the peri-infarct tissue suggests that 57Co may visualize a component of the inflammatory response. Divalent 57Co may be convenient to predict clinical prognosis after stroke.

Topics: Aged; Brain; Brain Ischemia; Cerebral Infarction; Cobalt Radioisotopes; Female; Humans; Leukocytes; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Two patients with subacute cerebral infarction underwent benzodiazepine receptor imaging using I-123-iomazenil and cerebral perfusion imaging with Tc-99m HMPAO and Tc-99m ECD. Iomazenil early images resembled HMPAO images, which demonstrated increased uptake in a part of the infarcted site. Iomazenil delayed images and ECD images showed reduced accumulation in the same area. Crossed cerebellar diaschisis was observed in HMPAO, ECD, and iomazenil early images, but it was not remarkable in iomazenil delayed images. These cases suggest that sequential iomazenil images visualized increased uptake with relatively impaired viability in the infarcted site and hypoperfusion with preserved viability in the contralateral cerebellar hemisphere, which could not be recognized without using both HMPAO and ECD in the subacute phase of cerebral infarction.

Topics: Adult; Brain; Cerebellum; Cerebral Infarction; Cerebrovascular Circulation; Cysteine; Female; Flumazenil; Humans; Iodine Radioisotopes; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Receptors, GABA-A; Technetium Tc 99m Exametazime; Temporal Lobe; Tissue Survival; 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

Luxury perfusion characterized by depressed metabolism compared with CBF might be changed by decreasing cerebral perfusion pressure during the sitting position. A 77-yr-old man with subacute cerebral infarction was studied with brain X-ray computed tomography (CT), raise-up test with 99mTc-d,1-hexamethylpropyleneamine oxime (HMPAO) brain single photon emission tomography (SPECT) and positron emission tomography (PET). Brain X-ray CT revealed a low-density area in the left middle cerebral artery (MCA) anterior area. Raise-up 99mTc-HMPAO brain SPECT revealed decreased uptake in the left MCA anterior area in the sitting position and subsequent supine 99mTc-HMPAO brain SPECT revealed hot accumulation there. PET study in the supine position demonstrated some differences between CBF and the cerebral metabolic rate for oxygen in the left MCA anterior area, indicating luxury perfusion. CBF in the area of luxury perfusion might be decreased during the sitting or standing position and increased during the supine position by dysautoregulation of the cerebral vessels in the luxury perfusion during the subacute infarct.

Topics: Aged; Animals; Brain; Cerebral Infarction; Humans; Male; Posture; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

This paper describes abnormal brain perfusion unexpectedly demonstrated by Tc-99m MAA total-body imaging in two children with intracardiac right-to-left shunt (RLS) associated with complex congenital heart disease. One child was a 12-year-old girl with asplenia cardiac syndrome and multiple cerebral infarctions caused by thromboembolism in the internal carotid artery, and the other child was a 6-month-old boy who developed focal cerebral infarction following shunt operation. In both children, the total-body imaging depicted the brain due to RLS, where radioactivity decreased unilaterally in the cerebral hemisphere. In the first patient, radioactivity also decreased in the contralateral cerebellum, suggesting the crossed cerebellar diaschisis phenomenon. These abnormalities in brain perfusion were confirmed by Tc-99m HMPAO brain SPECT. Careful review of the distribution of the radiotracer in the depicted brain on Tc-99m MAA total-body imaging may provide important information regarding brain perfusion in some patients with a high risk of stroke complication associated with RLS.

Topics: Brain; Carotid Artery Diseases; Carotid Artery, Internal; Cerebellum; Cerebral Infarction; Child; Female; Functional Laterality; Heart Defects, Congenital; Humans; Infant; Lung; Male; Radiopharmaceuticals; Technetium Tc 99m Aggregated Albumin; Technetium Tc 99m Exametazime; Thromboembolism; Tissue Distribution; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

[123I]Iomazenil is a specific radioligand for the central benzodiazepine receptor that may be useful as an indicator of the intactness of cortical neurons after focal cerebral ischemia. We evaluated the binding of this receptor in reperfused cortex among patients with ischemic stroke to detect viable neurons in cortex that appeared structurally intact on conventional neuroimaging studies.. Fourteen patients were selected by (1) angiography within 24 hours of onset showing embolic occlusion of an intracranial artery, (2) cerebral blood flow showing ischemia of moderate severity in 12 cases and spontaneous reflow in 2 cases, and (3) thrombolysis with reperfusion within 24 hours in most cases. Thirty reperfused cortical areas that remained structurally intact, 7 infarcted cortical areas, and 6 contralateral cerebellar areas with reduced blood flow were selected as regions of interest to estimate receptor binding 5 days to 23 months after the stroke. A two-compartment model was used to compute the distribution volume (Vd) of iomazenil in relative units, with Vd proportional to benzodiazepine receptor concentration. The side-to-side asymmetry ratio of Vd was calculated.. The mean asymmetry ratio was 0.89 +/- 0.11 (range, 0.64 to 1.05), 0.50 +/- 0.15 (range, 0.23 to 0.67), and 0.97 +/- 0.05 (range, 0.90 to 1.04) in reperfused cortex, infarcted cortex, and contralateral cerebellum, respectively. Compared with unity, both reperfused cortex and infarcted cortex showed significant decrease of Vd (P < .001). Contralateral cerebellum showing diaschisis had no reduction of Vd. On MRI, obtained 3 or 6 months after the stroke, mild cortical atrophy was observed in two reperfused areas where the asymmetry ratio was moderately reduced (0.64 and 0.80).. The reduction of benzodiazepine receptor concentration in reperfused cortex that remained structurally intact is likely to be the result of injury involving only a limited number of neurons (ie, incomplete infarction). Our data suggest that the degree of viability of ischemic cortex apparently salvaged by early reperfusion can be quantified by iomazenil.

Topics: Aged; Cerebellum; Cerebral Cortex; Cerebral Infarction; Cerebrovascular Circulation; Female; Flumazenil; Humans; Intracranial Embolism and Thrombosis; Iodine Radioisotopes; Magnetic Resonance Imaging; Male; Middle Aged; Models, Theoretical; Organotechnetium Compounds; Oximes; Receptors, GABA-A; Reperfusion; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Xenon Radioisotopes

We studied 26 patients with a single supratentorial infarction using 99mTc-HMPAO SPECT and MRI to investigate the phenomenon of crossed-cerebellar diaschisis (CCD).. From the total single-photon emission counts obtained from each cerebellar hemisphere, the percent difference between the contralateral (CCH) and ipsilateral (ICH) cerebellar hemispheres [delta %cbll = (CCH-ICH)/ ICH x 100] was calculated. Both SPECT (SVD) and MRI volume deficit (MVD) were measured to examine their relationship with CCD.. A CCD was observed in 12 of the 26 patients (46%) with cerebral infarction. There was no significant correlation between SVD and delta %cbll or MVD and delta %cbll in the patients with cerebral infarction. There were no significant differences in SVD and MVD between the patients with and without CCD. The frequency of CCD was significantly higher in the patients whose infarctions were in the frontoparietal lobes or the deep middle cerebral artery territory, including the basal ganglia and internal capsule (11/19) than in the patients whose infarctions were in other regions (1/7) (p = 0.048). The severely hemiparetic patients had a higher frequency of CCD and lower delta %cbll than the patients with milder or no hemiparesis (frequency, 5/5 compared with 6/18, p = 0.008; delta %cbll, -21.4% +/- 3.8% compared with -8.3% +/- 11.1%, p = 0.018). However, CCD also occurred in 5 of the 14 patients without hemiparesis and was not seen in 5 of the 12 hemiparetic patients. None of the patients with CCD demonstrated the apparent clinical signs of cerebellar dysfunction.. The location rather than the extent and severity of the lesion may be the major determinant for the occurrence and magnitude of CCD in patients with cerebral infarction. Our results also support the notion that CCD is a consequence of the interruption of the corticopontocerebellar pathway at the supratentorial level.

Topics: Adult; Aged; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Magnetic Resonance Angiography; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Topics: Aged; Aged, 80 and over; Basal Ganglia; Cerebral Infarction; Chorea; Dominance, Cerebral; Humans; Male; Neurologic Examination; Organotechnetium Compounds; Oximes; Parietal Lobe; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A 60-year-old right-handed man developed disorientation, antegrade amnesia and transient mild clouding of consciousness. The antegrade amnesia persisted for more than one year after its onset. T2-weighted MR images showed high signal intensity in the left anteromedial thalamus. 99mTc-HM-PAO SPECT revealed decreased uptake in the left frontal and temporal lobes. These SPECT findings were still observed a year later. These findings suggest that functional involvement of the frontal and temporal lobe connections with the dorsomedial nucleus, anterior nucleus, and the mamillothalamic tract in the anteromedial part of thalamus were responsible for the prolonged antegrade amnesia. We think that SPECT findings are important for evaluating the outcome of thalamic amnesia.

Topics: Amnesia; Cerebral Infarction; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon

The cerebellum has been implicated in higher-order behavior. Blood flow studies (SPECT) have shown that cerebral diaschisis can appear after cerebellar lesions and this phenomenon could serve as a basis for a potential neuropsychological derangement after cerebellar insults. Our objectives in this study were to delineate the neuropsychological profile after cerebellar stroke, to evaluate cerebral diaschisis as measured by SPECT and to correlate the findings. We prospectively studied 26 patients with cerebellar stroke and 16 subjects matched for age, sex and educational level as a control group. A neuropsychological battery test, MRI and cerebral SPECT were performed in both groups. We found that cerebellar stroke results in motor control impairment and mild naming deficit, whereas no dysfunction in declarative memory, language, visuospatial or executive abilities is evident. The anatomical distribution of the lesion does not seem relevant in terms of neuropsychological impairment or diaschisis. Both ipsilateral and contralateral diaschisis as a result of a cerebellar stroke are found, but this phenomenon does not seem to result in overt neuropsychological derangement.

Topics: Adult; Aged; Brain Mapping; Cerebellum; Cerebral Infarction; Dominance, Cerebral; Female; Humans; Male; Middle Aged; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To evaluate the EEG changes during seizures in children with drug resistant focal epilepsy who demonstrate hypoperfusion at the "seizure focus" interictally, but no perfusion change during the seizure.. Ictal EEG findings of six children with focal epilepsy who demonstrated hypoperfusion on rCBF SPECT after an interictal injection of (99)Tc(m) HMPAO concordant with the seizure focus, but who did not demonstrate rCBF change after an ictal injection (group 1) were reviewed. These were contrasted with the EEG data of six children matched as closely as possible for age, type of epilepsy, and pathology who did show hyperperfusion at the seizure focus on ictal scan when compared with the interictal study (group 2).. The children in group 1 showed slowing of the EEG at the time of the (99)Tc(m) HMPAO injection relative to that seen at the onset of the seizure. Those in group 2 showed rhythmic activity, or sharp waves, or both on EEG at the time of injection. This last change was also seen consistently when the EEG data of a further 13 children who also showed ictal hyperperfusion at the seizure focus were reviewed.. Ictal rCBF does not invariably increase at the seizure focus in patients with drug resistant focal epilepsy.

Topics: Adolescent; Adult; Brain Diseases; Brain Neoplasms; Cerebral Infarction; Child; Cysts; Drug Resistance; Electroencephalography; Epilepsies, Partial; Hippocampus; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To clarify whether muscarinic acetylcholine receptor (mAChR) binding can be a viable muscarinic neuronal marker which provides therapeutic information different from perfusional information in global brain, we evaluated the discrepancy between the distribution of cerebral blood flow (CBF), mAChR and its five subtypes of messenger ribonucleic acid (mRNA) in the acute (n=9) and chronic (n=8) phases of a middle cerebral artery (MCA) occlusion model and in sham-operated controls (n=6). In the acute phase, regional CBF was markedly reduced in the MCA territory, whereas mAChR was not reduced and the mRNA was reduced only slightly. In the chronic phase, mAChR was reduced markedly in the infarcted lesion and the mRNA was also reduced. The mAChR was slightly reduced in the ipsilateral substantia nigra and pontine nucleus because of remote effects; however, regional CBF in the substantia nigra was slightly increased and did not change in the pontine nucleus. The discrepancy between CBF and mAChR was clarified, and the tendency toward a reduction in mRNA in the acute ischaemic region without a reduction in mAChR suggested the presence of cholinergic neurons which were viable but hypometabolic. It is concluded that mAChR imaging may be of value for the assessment of the viable cholinergic neuron density in vivo.

Topics: Animals; Autoradiography; Brain; Cerebral Arteries; Cerebral Infarction; Cerebrovascular Circulation; Male; Organotechnetium Compounds; Oximes; Quinuclidinyl Benzilate; Rats; Rats, Sprague-Dawley; Receptors, Muscarinic; RNA, Messenger; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Hemorrhagic transformation (HT) is a common evolution of large-volume ischemic lesions, particularly of cardioembolic origin. We used transcranial Doppler ultrasound (TCD), single-photon emission computed tomography (SPECT) with 99mTc-hexamethylpropyleneamine oxime (HMPAO), and the Toronto Embolic Scale (TES) to decide (1) whether TCD, HMPAO-SPECT, and TES can improve on clinical and CT tests to predict spontaneous HT and (2) whether SPECT can help to predict the outcome of symptomatic HT.. Prognostic criteria included Canadian Neurological Scale (CNS) scores < or = 50 on admission, early ischemic changes on CT, M1 middle cerebral artery occlusion on TCD, the focal absence of brain perfusion on SPECT, and a high risk of cardiogenic embolism on TES.. In part 1, 85 consecutive patients admitted within the first 6 hours were studied. No patient received thrombolysis. HT was found in 11 patients (13%) at 3 to 5 days. Admission CNS and CT were not predictive of HT: odds ratios (95% confidence intervals) were 0.49 (0.18 to 1.23) (P = .1) and 0.88 (0.23 to 3.45) (P = .8), respectively, TCD, SPECT, and TES were significant predictors of HT (P < .05), as follows: TCD, 8.67 (1.42 to 70.59); SPECT, 17.40 (2.69 to 170.89); and TES, 18.13 (2.6 to 406.86). In part 2, 490 consecutive patients were studied and 21 (4%) had symptomatic HT, of which 12 had focal hypoperfusion on SPECT at 4 days after stroke onset and 9 had focal hyperperfusion. Patients with hypoperfusion had larger CT lesions (115 +/- 97 versus 42 +/- 29 cm3; P = .04) and poorer outcome at 2 weeks (CNS, 38 +/- 45 versus 96 +/- 10; P = .001), including death (6/12 versus 0/9; P = .04); compared with those with hyperperfusion on SPECT.. High risk of cardioembolism, M1 middle cerebral artery occlusion, and absence of collateral flow evaluated by TES, TCD, and SPECT help to identify patients at risk for spontaneous HT. Although TES was the most powerful predictor of HT, SPECT is the best single adjunct to the triage of clinical and CT tests. Patients with brain hyperperfusion on HMPAO-SPECT after symptomatic HT have better chances for recovery.

Topics: Anticoagulants; Cerebral Hemorrhage; Cerebral Infarction; Coronary Thrombosis; Humans; Intracranial Embolism and Thrombosis; Organotechnetium Compounds; Oximes; Prognosis; Prospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Ultrasonography, Doppler, Transcranial

Topics: Aged; Cerebellar Nuclei; Cerebellum; Cerebral Cortex; Cerebral Infarction; Cerebrovascular Circulation; Humans; Male; Mesencephalon; Neural Pathways; Ophthalmoplegia; Organotechnetium Compounds; Oximes; Pons; Radiopharmaceuticals; Syndrome; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon

Tc-HMPAO isotope brain scans were performed in three patients who received hyperbaric oxygen treatment following carbon monoxide poisoning. Cerebral perfusion imaging provides an index of severity of the initial cerebral damage which correlated with outcome.

Topics: Adult; Brain; Carbon Monoxide Poisoning; Cerebral Hemorrhage; Cerebral Infarction; Cerebrovascular Circulation; Fatal Outcome; Female; Forecasting; Humans; Hyperbaric Oxygenation; Male; Organotechnetium Compounds; Oximes; Purpura; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Treatment Outcome

Single photon emission computed tomography (SPECT) using [123I]iomazenil (radioligand of central-type benzodiazepine receptors) was employed to examine two patients with striatocapsular infarction. Patient 1 was a 61-year-old female with motor aphasia and hemiplegia on the right side. Magnetic resonance imaging (MRI) showed a lesion in the anterior limb of internal capsule and putamen on the left side. SPECT using 99mTc-HMPAO revealed a reduction of cerebral blood flow (CBF) in the frontoparietal region on the left side, but the delayed images in SPECT using [123I]iomazenil showed only a mild decrease of accumulation in the frontal lobe. Patient 2 was a 55-year-old male with hemiplegia on the left side. MRI showed a lesion localized in the basal ganglia and posterior limb of the internal capsule on the right side. SPECT using 99mTc-HMPAO revealed a reduction of CBF in the frontoparietal region on the right side and in the cerebellar hemisphere on the left side, but the delayed images in SPECT using [123I]iomazenil showed little decrease of accumulation in parietal lobe. The discrepancy between CBF and receptor images suggested that cortical hypoperfusion on striatocapsular infarction might reflect hypometabolism due to disconnection of the neuronal network between subcortical structure and cortex.

Topics: Aphasia; Basal Ganglia; Cerebral Cortex; Cerebral Infarction; Cerebrovascular Circulation; Female; Flumazenil; Hemiplegia; Humans; Iodine Radioisotopes; Magnetic Resonance Imaging; Male; Middle Aged; Neostriatum; Radionuclide Imaging; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The brain benzodiazepine (BZD) receptor distribution in patients with chronic cerebrovascular disease was assessed with 123I-iomazenil (IMZ) SPECT, and the findings were compared with the data for the cerebral blood flow (CBF) and cerebral metabolism.. We examined nine patients with chronic cerebrovascular diseases, six patients with cerebral infarction and three with moyamoya disease. Iodine-123-IMZ SPECT images were obtained for 15 min, 3 hr after the administration of 167 or 222 MBq 123I-IMZ. In seven patients, the CBF and oxygen metabolism were measured by the 50 steady-state method. In two patients, the CBF and glucose metabolism were measured by 99mTc-HMPAO SPECT and 18F-fluoro-2-deoxy-D-glucose-PET, respectively. The brain was initially classified into 18 regions, and abnormalities in the BZD receptor distribution, CBF and cerebral metabolism were visually evaluated. The count ratio of lesion-to-contralateral normal region (L-to-C ratio) was then used for comparison.. In the core of the infarct, the 123I-IMZ uptake decreased (L-to-C ratios of the blood flow 0.42 +/- 0.26; metabolism 0.45 +/- 0.24; and 123I-IMZ uptake 0.46 +/- 0.14). In the peri-infarct region, the 123I-IMZ uptake slightly decreased (L-to-C ratios of 0.81, 0.82 and 0.89, respectively). In the region of misery perfusion, the 123I-IMZ uptake was preserved (L-to-C ratios of 0.73, 1.07 and 1.02, respectively). In the remote deafferentiated areas in the ipsilateral cerebrum, the 123I-IMZ uptake was preserved (L-to-C ratios of 0.76 +/- 0.10, 0.75 +/- 0.04 and 0.98 +/- 0.05, respectively). In the remote areas in the contralateral cerebellum, the 123I-IMZ uptake was preserved (L-to-C ratios of 0.84 +/- 0.08, 0.85 +/- 0.04 and 0.94 +/- 0.05, respectively).. The BZD receptor distribution, as measured by 123I-IMZ SPECT, is not considered to reflect neuronal function, but it may reflect neuronal cell viability. Iodine-123-IMZ SPECT may, therefore, hold promise as a potential probe for neuronal damage.

Topics: Brain; Cerebral Infarction; Cerebrovascular Circulation; Female; Flumazenil; Humans; Iodine Radioisotopes; Male; Middle Aged; Moyamoya Disease; Radiopharmaceuticals; Receptors, GABA-A; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Cerebral Infarction; Cerebrovascular Circulation; Humans; Magnetic Resonance Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

The role of single-photon emission CT (SPECT) in the prognosis of cerebral infarction is controversial, but most studies report that SPECT using a variety of radiopharmaceutical agents gives useful prognostic information. Only one study has questioned whether acute perfusion deficits independently add to a valid clinical prognostic score. This study was limited to middle cerebral artery territory infarcts and was negative. We present data on the prognostic utility of SPECT using 99mTc-hexamethylpropyleneamine oxime (HMPAO) in cerebral infarction, unselected by site.. Fifty consecutive unselected patients admitted to the hospital with acute cerebral infarction, of whom 10 died and 7 withdrew, had SPECT performed serially at onset and at 1 week and 3 months after stroke onset using 99mTc-HMPAO and the NOVO 810 dedicated high-resolution head tomograph. Clinical severity at presentation and outcome was measured with the Canadian Neurological Scale and the Barthel Index. Infarct volumes were measured from both the SPECT and CT scans. The data for the 43 subjects who completed the study or died were evaluated to determine the most powerful prognostic measures. Predictors were the Canadian Neurological Scale score at onset and 1 week, the Barthel Index at 1 week, the CT infarct volume typically done between 3 and 7 days after stroke onset, and the infarct volumes at the first and second SPECT. Outcome measures were the Canadian Neurological Scale score and Barthel Index score at 3 months, scored as zero for those patients who died.. The clinical prognostic indicators correlated with the outcome measures, with coefficients between .617 and .821 (P < .0006 in all cases). The Canadian Neurological Scale score measured at 1 week was the best of these. Infarct volumes measured from SPECT correlated less well (coefficients between -.518 and -.683, P < .0019 in all cases). CT infarct volume was the poorest predictor. Although SPECT infarct volumes predicted outcome, they did so less well than clinical examination. Spontaneous infarct reperfusion did not affect outcome.. Although the measurement of infarct volume on SPECT using 99mTc-HMPAO provides a predictor of stroke outcome, it is not a better predictor than the Canadian Neurological Scale score.

Topics: Acute Disease; Adult; Cerebral Infarction; Follow-Up Studies; Forecasting; Humans; Logistic Models; Magnetic Resonance Imaging; Neurologic Examination; Organotechnetium Compounds; Oximes; Prognosis; Prospective Studies; Reperfusion; Survival Rate; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Treatment Outcome

Cerebral infarction and prolonged regional hypoperfusion have been described in patients with transient ischemic attacks (TIAs). The aim of this study was to compare the sensitivity of single-photon emission CT (SPECT) with that of brain CT and to evaluate the clinical significance of differentiation of TIA patients with or without focal hypoperfusion.. From a hospital-based population, we studied the SPECT and CT findings in 76 consecutive patients, without a stroke history, who presented with TIA in the carotid artery territory. The recorded variables were the time of SPECT, imaging (<36 or > or = 36 hours), clinical presentation, history of previous TIA(s), duration of the presenting attack (<2 or > or = 2 hours), vascular risk factors, and etiology. We used both visual and semiquantitative analyses for the SPECT evaluation. Acetazolamide challenge was not performed.. The overall SPECT sensitivity was 36% (27/76). When brain CT and SPECT were performed in the same patients, the SPECT sensitivity was significantly higher than that of CT (19/59 [32%] versus 8/59 [14%]; P=.007). The SPECT sensitivity was not dependent on the time of investigation, duration of attacks, history of TIA(s), or the clinical presentation. The vascular risk and etiologic factors were not significantly different between the patients with or without prolonged focal hypoperfusion. Logistic regression did not identify any variable to discriminate the two groups.. Despite its better sensitivity compared with CT, SPECT performed without the acetazolamide test provides no additional clinically useful information on the vascular risk factors and etiology in TIA patients.

Topics: Acetazolamide; Adult; Aged; Aged, 80 and over; Brain; Carotid Arteries; Cerebral Infarction; Cerebrovascular Circulation; Cohort Studies; Female; Humans; Ischemic Attack, Transient; Logistic Models; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prospective Studies; Risk Factors; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Vasodilator Agents

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

Various observations on the cerebellar vasoreactivity in crossed cerebellar diaschisis (CCD) have previously been reported. The purpose of this study is to clarify the difference between oxygen-15 H2O positron emission tomographic (PET) and technetium-99m hexamethylpropylene amine oxime (HMPAO) single-photon emission tomograph (SPET) findings in CCD and to evaluate the effect of the absolute values of the cerebellar blood flow as measured by 15O-H2O PET on the 99mTc-HMPAO SPET findings. The subjects comprised 15 patients with a supratentorial infarct and CCD. The cerebellar blood flow increased by about 40% at 5 and 20 min after acetazolamide i.v. on both the CCD and the non-CCD side, as measured by 15O-H2O PET. The percentage differences in cerebellar blood flow between the CCD and the non-CCD side were -22.3%+/-5.7% in the resting state, -19. 6%+/-6.4% at 5 min after acetazolamide i.v. and 21.5%+/-6.7% at 20 min after acetazolamide i.v., as measured by 15O-H2O PET, while they were -10.6%+/-5.5% in the resting state and -5.6%+/-5.1% at 5 min after acetazolamide i.v., as measured by 99mTc-HMPAO SPET. After Lassen's linearization correction, the latter two measurements were -16.2%+/-7.7% and -9.6%+/-8.9%, respectively. The effect of acetazolamide did not differ between the CCD and the non-CCD side in 15O-H2O PET, while a greater response on the CCD side was observed in 99mTc-HMPAO SPET, even after Lassen's linearization correction. It is concluded that acetazolamide HMPAO SPET may overestimate the cerebellar vascular response on the CCD side (or underestimate it on the non-CCD side).

Topics: Acetazolamide; Adult; Aged; Cerebellum; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Oxygen Radioisotopes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Water

Topics: Acute Disease; Cerebral Infarction; Follow-Up Studies; Forecasting; Humans; Logistic Models; Neurologic Examination; Organotechnetium Compounds; Outcome Assessment, Health Care; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The purpose of this study is to assess the clinical usefulness of super dynamic SPECT of 99mTc-HM-PAO. Six patients with unilateral occlusion of middle cerebral artery (MCA) or internal carotid artery (ICA) in the chronic phase, and 5 patients with subacute cerebral infarction were studied. We used a ring-type SPECT "HEADTOME." Two types of collimator were used: a high sensitivity (HS) collimator for super dynamic scan and a high resolution (HR) collimator for static scan. First, the intravenous constant infusion of 99mTc-HM-PAO (925-1480 MBq) for 1 minute was started. After 30 seconds from the beginning of the injection, we performed the 12 seconds/frame super dynamic SPECT for 2 minutes. Then, the static SPECT for 10 minutes was done. For semiquantitative analyses, differential percentage of regional activity between affected and non-affected hemispheres was calculated in the 6th frame image of super dynamic SPECT and static SPECT image. In all 6 patients with unilateral occlusion of MCA and ICA, super dynamic SPECT images showed the better contrast of low perfusion areas in comparison with the static SPECT images. In 5 patients with subacute cerebral infarction who showed focal hyperactivities on static SPECT, focal hyperactivities (hyperperfusion or hyperemia) were displayed in 3 cases, whereas, focal hypo- or isoactivities (hypo- or isoperfusion) were shown in 2 cases on super dynamic SPECT. However, all patients with subacute cerebral infarction showed hyperfixation on static SPECT as compared with super dynamic SPECT. Although the image quality on super dynamic SPECT is not as high as that on static SPECT, cerebral hemodynamics would be detected with less backdiffusion of 99mTc-HM-PAO from the brain to blood, and with less accumulation of hydrophilic components in subacute infarct region. In conclusion, super dynamic SPECT in early distribution of 99mTc-HM-PAO using dedicated SPECT device might be helpful to detect cerebral perfusion close to true cerebral blood flow distribution.

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

A unique infarction limited to the posterior insula and intrasylvian parietal opercular cortex produced a subtype of conduction aphasia, characterized by a predominance of semantic paraphasias. Temporal lobe hypoperfusion seen on hexamethylpropyleneamineoxime single-photon emission computed tomography in the absence of any signs of ischemia suggested that cortical diaschisis played a role in the emergence of this syndrome.

Topics: Aphasia, Conduction; Cerebral Cortex; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Parietal Lobe; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

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 main objective of this study was to assess whether 99mTc-HMPAO brain SPECT imaging can identify patients at high risk of developing an infarct following permanent carotid occlusion in the course of brain surgery.. Test balloon occlusion of the internal carotid artery was performed in 44 patients with a variety of head and neck tumors or aneurysms. Technetium-99m-HMPAO was injected intravenously while the balloon was initiated and a SPECT study was obtained 30 min later. Follow-up CT scans were obtained routinely for all patients at 2 wk and 1 mo following surgery, or earlier when necessary. Thirty patients and five normal volunteers had semiquantitative analysis of cerebral perfusion.. Twenty-six patients demonstrated ipsilateral perfusion abnormalities during trial occlusion. Eight patients in this group underwent bypass grafting prior to sacrifice of the artery: two resulting in infarcts. Eighteen patients had symmetric cerebral perfusion during occlusion and four of these patients underwent permanent therapeutic carotid occlusion; three patients had subsequent infarcts and the fourth patient had an impending stroke.. Patients with symmetric cerebral perfusion measured by 99mTc-HMPAO SPECT may still have a high long-term complication rate following carotid sacrifice. The scan findings in these patients were not predictive of the outcome. Patients with asymmetric cerebral perfusion had alternative therapeutic approach to carotid sacrifice and most of them had good surgical outcomes.

Topics: Brain; Brain Neoplasms; Carotid Artery, Internal; Catheterization; Cerebral Infarction; Cerebrovascular Circulation; Female; Follow-Up Studies; Head and Neck Neoplasms; Humans; Intracranial Aneurysm; Male; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Predictive Value of Tests; Risk Factors; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Carotid Artery, Internal; Catheterization; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Predictive Value of Tests; Risk Factors; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Brain 99Tcm-HMPAO single photon emission tomography (SPET) and 1H-MRS (proton magnetic resonance spectroscopy) were used to determine correlations between alterations in regional cerebral blood flow (rCBF) and changes in neuronal metabolites in 21 patients (28 examinations) with ischaemic cerebral infarction examined in different phases. rCBF was determined semi-quantitatively using Lassen's linearization algorithm. SPET provided evidence of the hypoperfused site of necrosis within a few hours after the acute event and alterations in rCBF were detected in both the infarcted and diaschistic areas at all stages. 1H-MRS was used to monitor the concentration of the following metabolites: N-acetyl-aspartate (NAA), creatine and phosphocreatine (CR + PCr), compounds containing choline (Cho) and lactate (Lac). A significant correlation was found between reduction in rCBF and a fall in NAA and Cr + PCr in both the acute and chronic phases, but not during "luxury perfusion' in the subacute phase. The presence of LAC in the infarcted area up to 9 months post-ictus was totally unexpected. Simultaneous SPET and 1H-MRS thus provides additional information regarding the physiopathogenesis of cerebral ictus by clarifying the relation between alterations in rCBF and biochemical neuronal changes. We believe that NAA and Cr + PCr concentrations are the best expression of agreement between flow and metabolism in infarcted areas, particularly with regard to hypoperfused areas not clearly detectable by magnetic resonance imaging in the early post-ictus stage.

Topics: Adult; Aged; Aspartic Acid; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; Choline; Creatine; Female; Humans; Lactates; Lactic Acid; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Phosphocreatine; Protons; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Aged; Aged, 80 and over; Basal Ganglia Diseases; Blood Flow Velocity; Brain Mapping; Cerebral Infarction; Chorea; Corpus Striatum; Dominance, Cerebral; Humans; Male; Neural Inhibition; Neurons; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Thalamic Nuclei; Thalamus; Tomography, Emission-Computed, Single-Photon

This study was performed to study the dynamics of polymorphonuclear leukocyte (PMNL) accumulation in human cerebral infarction and its association with neurological outcome and brain lesion.. A total of 88 patients diagnosed as having hemispheric ischemic stroke were examined. PMNL accumulation was studied using technetium-99m hexamethylpropyleneamine oxime (99mTc HMPAO)-labeled leukocyte brain single-photon emission computed tomography (SPECT). Volume of brain infarction was evaluated by CT scan. The Mathew Scale was used for neurological assessment. Dynamics of PMNL accumulation was studied at 3 to 6, 6 to 12, and 12 to 24 hours and 6 to 9, 28 to 30, and 90 days after stroke onset. In parallel, at admission, at 6 to 9 days, and at 28 to 30 days neurological outcome and infarction volume were evaluated.. Generally, PMNL accumulation progressively increased during 6 to 24 hours after stroke, remained at a high level up to 6 to 9 days and then declined. With the use of cluster analysis, all patients were subdivided into three groups: patients with severe PMNL accumulation that dramatically increased within 12 hours after stroke onset and persisted even at 28 to 30 days (group A); those with moderate PMNL accumulation that significantly decreased at 30 days (group B); and those with mild PMNL accumulation that decreased at 6 to 9 days (group C). Baseline neurological deficit and brain tissue damage at admission appear to be at a similar level for all groups of patients. In dynamics, however, in patients with severe PMNL accumulation, neurological outcome was worse and infarction volume larger than in patients with less marked PMNL accumulation.. The present clinical study confirms that PMNLs intensively accumulate in the regions of cerebral infarction. The present study revealed that this accumulation correlated with the severity of the brain tissue damage and poor neurological outcome.

Topics: Aged; Brain; Cerebral Infarction; Female; Humans; Male; Middle Aged; Nervous System; Neutrophils; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

We evaluated the posterior circulation in patients with moyamoya disease by SPECT and MRI.. Six patients with idiopathic moyamoya disease were studied by SPECT, MRI and angiography. Patients received an injection of 555-740 MBq of 99mTc-HMPAO, after which SPECT images were taken. The cerebral-to-cerebellar activity ratio in five cerebral regions was calculated to assess the regional cerebral blood flow (rCBF). The SPECT and MRI findings were then compared with angiographic.. Of the 12 posterior cerebral arteries (PCAs) in the six patients studied, seven PCAs (58%) in five patients had a stenotic or occluded lesion. Furthermore, rCBF in all five regions significantly decreased as the degree of steno-occlusive lesions of the PCA progressed. No significant correlation, however, was found between the steno-occlusive lesions of the internal carotid artery bifurcation and the rCBF. The rCBF significantly decreased in the absence of leptomeningeal collateral vessels from the PCA to the anterior circulation. On the basis of the MR images, the frequency of cerebral infractions significantly increased in patients with steno-occulasive PCA lesions.. The rCBF in moyamoya disease decreases proportionally with the degree of steno-occlusive lesions of the PCA. The steno-occlusive PCA lesions decrease the number of leptomeningeal collateral vessels to the anterior circulation, thereby causing severe cerebral ischemia that is likely to result in infractions.

Topics: Adolescent; Adult; Carotid Artery, Internal; Carotid Stenosis; Cerebral Angiography; Cerebral Infarction; Cerebrovascular Circulation; Child; Collateral Circulation; Constriction, Pathologic; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Moyamoya Disease; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To clarify the clinical significance of fibrinolytic therapy for acute ischemic stroke.. We analyzed findings in 18 patients with occlusion of a major artery in respect to cerebral blood flow thresholds for infarction. Nine of these patients had shown complete recanalization just after the treatment, between 3.5 and 7.25 hours after symptom onset, and the other nine had shown no change. Cerebral blood flow was measured by single-photon emission CT using 99mTC-labeled hemamethylpropyleneamine oxime and assessed semiquantitatively: multiple regions of interest were placed on the section images and two parameters, the R/CL ratio and the R/CE ratio, were calculated (where R represents a mean count of the region of interest in the affected hemisphere, CL on the opposite side, and CE in the cerebellar hemisphere on the affected ischemic side).. Reperfusion significantly reduced the development of infarction in the regions of interest with an R/CL ratio between 0.65 and 0.85 or an R/CE ratio between 0.55 and 0.75. No correlation was observed between the development of infarction and the duration of ischemia. The cerebral blood flow threshold in patients without recanalization was higher than that in patients with recanalization.. Reperfusion achieved by fibrinolytic therapy in the acute stage can save ischemic brain within a limited cerebral blood flow value.

Topics: Aged; Brain; Brain Ischemia; Cerebral Infarction; Dominance, Cerebral; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Humans; Intracranial Embolism and Thrombosis; Male; Middle Aged; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Tissue Plasminogen Activator; Tomography, Emission-Computed, Single-Photon; Urokinase-Type Plasminogen Activator

The sensitivity of single-photon emission computed tomography (SPECT) in evaluating posterior circulation infarcts compared with that of computed tomography (CT) or magnetic resonance imaging (MRI) remains unknown. In a hospital-based population, the authors studied SPECT, CT, and MRI in 35 consecutive patients presenting with acute infarction clinically localized in the thalamus (7), posterior cerebral artery (PCA) territory (15), brainstem (19), and cerebellum (3). Multiple infarcts were noted in 8 patients. Overall, the SPECT sensitivity was lower than that of MRI (21% vs 93%, p = 0.004) and CT (42% vs 65%, p = 0.046). The SPECT and CT sensitivities were not significantly different (67% vs 73%) for PCA infarcts. Performed within 24 hours, SPECT showed a relevant hypoperfusion in all PCA infarcts. For brainstem infarcts, CT (33%, p = 0.074) and MRI (91%, p = 0.004) were more sensitive than SPECT, which showed no hemispheric hypoperfusion. The sensitivity of the three imaging techniques was 100% for large cerebellar infarcts. For the small group of thalamic infarcts, the SPECT, CT, and MRI sensitivities were 14, 71, and 100%, respectively. Thus, SPECT compared to CT and MRI is not helpful in the subacute phase to localize PCA and cerebellar infarcts and is of limited value for thalamic infarcts. In the first hours, the absence of cerebral hypoperfusion in brainstem infarcts may help to differentiate them from hemispheric infarcts usually associated with profound hypoperfusion.

Topics: Aged; Aged, 80 and over; Brain Stem; Cerebellar Diseases; Cerebellum; Cerebral Arteries; Cerebral Infarction; Cerebrovascular Circulation; Cohort Studies; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prospective Studies; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

A 56-year-old man with Staphylococcal aureus septicemia and clinically suspected infective endocarditis was imaged using Tc-99m HMPAO leukocytes. Although abnormal uptake was seen at 3 hours after injection, 24-hour images demonstrated marked concentration of radiolabeled leukocytes in a myocardial abscess and large posterior parietal infarct. In addition, multiple splenic infarcts were shown. The Tc-99m labeled leukocyte scan proved to be an excellent whole body screening procedure for diagnosing sites of infection and infarction in this patient.

Topics: Bacteremia; Cerebral Infarction; Endocarditis, Bacterial; Humans; Leukocytes; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Splenic Infarction; Staphylococcal Infections; Technetium Tc 99m Exametazime; Time Factors

It is quite difficult to confirm the diagnosis of demential disorders, including senile dementia of the Alzheimer type (SDAT) by clinical means only. Through the combination of 99mTc-HMPAO brain SPECT and serum vitamin B12 determination it was hoped to speed up and improve the diagnosis of SDAT. 116 patients who had been divided into four groups according to their defect pattern in the 99mTc-HMPAO brain SPECT 17 very probably had SDAT; of these 15 showed a defect-pattern with brain SPECT which could be associated to SDAT. The majority of SDAT patients had serum vitamin B12 levels in the lower normal range or pathologically below that range. Both investigations contributed to establishing the SDAT diagnosis without replacing other investigations. The determination of serum vitamin B12 does not require any major additional effort.

Topics: Aged; Alzheimer Disease; Brain; Cerebral Infarction; Dementia; Diagnosis, Differential; Humans; Organotechnetium Compounds; Oximes; Reference Values; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vitamin B 12

For semiquantification of SPECT studies we tried to calculate cerebral 99mTc-HMPAO uptake related to injected dose and estimated brain volume. The method was applied to SPECT investigations of 27 patients who had at least one ischaemic attack and a confirmed 80-100% stenosis of the corresponding internal carotid artery (ICA). Vascular reactivity was tested by parenteral administration of acetazolamide (AZ). Increase in HMPAO uptake after AZ was evident in both hemispheres, although the increase (AZ effect) was significantly lower in the affected hemisphere (+24% versus +28%). No interhemispheric uptake differences were seen in patients with largely normal SPECT studies, although local asymmetries in HMPAO deposition were visible. Patients with low density lesions on CT and with a well-demarcated lesion in the same location on SPECT revealed interhemispheric uptake differences, with lower uptake on the affected side. This was not due solely to alterations in the lesion, but also to reduced HMPAO uptake and AZ effect in the surrounding area. The AZ effect showed no correlation with angiographic findings, indicating no major haemodynamic influence of the ICA stenosis on cerebral hemisphere perfusion. Calculated cerebral HMPAO uptake changes after AZ administration were in good accordance with absolute cerebral blood flow measurements, and made interindividual comparisons possible. However, as changes in the area around an infarct or local reduction in vascular reserve may not be reproduced adequately by uptake calculations, visual inspection is still necessary.

Topics: Acetazolamide; Adult; Aged; Brain; Brain Mapping; Carotid Artery, Internal; Carotid Stenosis; Cerebral Cortex; Cerebral Infarction; Dominance, Cerebral; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Regional Blood Flow; 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

Regions of decreased cerebral blood flow are often seen on single-photon emission computed tomography (SPECT) after stroke and have been widely reported to add to the clinical deficit. However, such reports have not distinguished between correlation and causation. We analyzed 124 serial SPECT scans performed in 50 patients to assess the role of diaschisis in the clinical deficit after stroke.. SPECT with the use of 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) was performed in a prospective, unselected series of 50 patients with cerebral infarcts studied at a median of 1.1, 6.8, and 95 days after ictus. Patients were also assessed with the use of the Canadian Neurological Scale, the Barthel Index, a neuropsychological evaluation, and infarct volume measurement.. One hundred twenty-four serial SPECT scans were done in 50 patients. Diaschisis was identified at 168 sites. There was insufficient correlation between diaschisis and the clinical measurements to support the suggestion that diaschisis independently causes clinical deficits beyond those due to the infarct itself. Unlike the clinical status, diaschisis showed little tendency to resolve during the 3-month follow-up period of the study. Several of the instances of correlation were shown to be of a noncausal kind, with both the diaschisis and the clinical deficit being due to the lesion directly; there was no known mechanism for the diaschisis to cause the clinical deficit.. Diaschisis does not independently add to the clinical deficit after stroke. It is more likely that it simply represents part of the damage done by the stroke.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebral Infarction; Female; Follow-Up Studies; Humans; Male; Middle Aged; Organ Specificity; Organotechnetium Compounds; Oximes; Prospective Studies; Psychological Tests; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

Topics: Brain; Cerebral Infarction; Humans; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Topics: Aged; Brain; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Organotechnetium Compounds; Oximes; Predictive Value of Tests; Prognosis; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Three patients with subacute ischemic cerebral infarction examined by SPECT with 99mTc-ECD and PET within the same day showed signs of luxury perfusion in the subacute phase, which is between 9 to 20 days after the onset. A 99mTc-HMPAO SPECT study was also performed within 2 days of the ECD-SPECT study. ECD-SPECT images of three patients displayed a focal decreased uptake in the infarcted lesions, while in infarcted foci, there was almost equivalent or increased CBF compared to normal and unaffected areas, decreased CMRO2, and high HMPAO uptake. The ECD-SPECT results were similar to those of CMRO2 rather than CBF, though the HMPAO-SPECT image was similar to that of CBF. In one patient, HMPAO images revealed hyperfixation of the tracer. In the chronic phase and in the acute phase before 5 days after the onset, there were no discrepancies among the ECD-SPECT, CBF, HMPAO-SPECT, and CMRO2 images. These observations indicated that 99mTc-ECD is a good indicator of damaged brain tissues in subacute ischemic infarction. They also suggested that 99mTc-ECD is a potential agent with which to evaluate cerebral tissue viability in some pathological states of cerebrovascular disease. The characteristics may be suitable for confirming the effects of thrombolytic therapy in acute ischemia, because these conditions often show signs of luxury perfusion when the therapy is successful.

Topics: Aged; Brain; Cerebral Infarction; Cerebrovascular Circulation; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Oxygen Consumption; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Intracerebral uptake of methylene diphosphonate (MDP) was unexpectedly found in metastatic work-up of lung cancer. The history of the 52-year-old patient revealed a sudden onset of weakness of right limbs 10 days ago. Technetium-99m diethylenetriamine pentaacetate (Tc-99m DTPA) brain scan and Tc-99m hexamethyl propylene amine oxime (HMPAO) brain single photon emission computed tomography (SPECT) were done, and both showed abnormality in the left temporoparietooccipital region corresponding to the territory of left middle cerebral artery. A repeated bone scan four months later showed complete resolution of the intracerebral Tc-99m MDP uptake. We present this case to emphasize the importance of complementary and enhanced radionuclide images.

Topics: Brain; Cerebral Infarction; Humans; Lung Neoplasms; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Technetium Tc 99m Medronate; Technetium Tc 99m Pentetate; Tomography, Emission-Computed, Single-Photon

Topics: Acute Disease; Adult; Blood Flow Velocity; Brain Edema; Cerebral Arteries; Cerebral Infarction; Cerebrovascular Circulation; Cysteine; Humans; Ischemic Attack, Transient; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon

Technetium-99m-HMPAO can be used to evaluate abnormal brain perfusion in the hyperacute stage of stroke.. We investigated cerebral blood flow using 99mTc-HMPAO SPECT in 31 patients within 6 hr after the onset of cerebral infarction and analyzed the relationship between abnormal perfusion and morphological changes on follow-up CT scans. Patients were classified into an infarct group and a noninfarct group, and the lesions on SPECT images were divided into infarct and peri-infarct regions.. Among a total of 30 infarct regions, three lesions studied at 1.5, 2.5 and 5 hr after the ictus showed local hyperperfusion suggestive of early postischemic hyperemia, while the other 27 lesions demonstrated local hypoperfusion. All of the peri-infarct regions showed moderate hypoperfusion. The noninfarct group consisted of five patients, four of whom showed no perfusion abnormalities. The lesion-to-contralateral radioactivity ratios for the infarct and peri-infarct regions were respectively 0.48 +/- 0.14 and 0.75 +/- 0.10 in the patients with hypoperfusion, while the right-to-left ratio in the noninfarct group was 0.97 +/- 0.10.. This SPECT study of cerebral blood flow demonstrates that local hyperperfusion occurs in some infarcts even within 6 hr of onset and that infarcted and morphological viable brain can be distinguished by a lesion-to-contralateral radioactivity ratio of 0.6 within this time range.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebral Angiography; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) single photon emission computed tomographic (SPECT) brain imaging performed in conjunction with balloon test occlusion of the carotid artery has been used to assess risk of neurologic sequelae that might follow permanent surgical ligation of the artery. The predictive value of cortical hypoperfusion during temporary carotid occlusion for adverse neurologic events has been debated in previous publications. We believe that the risk of an adverse event is greater when a reduction in cortical perfusion during balloon test occlusion is associated with crossed cerebellar diaschisis (CCD). To test our hypothesis we evaluated the results of 27 99Tcm-HMPAO SPECT brain studies obtained in association with balloon test occlusions of the carotid artery. In each case we correlated clinical outcome with the presence or absence of regional decreases in cerebral perfusion and CCD. All of the 27 patients were free of neurologic symptoms during the balloon test occlusion. Seventeen of the 27 scintigraphic studies were felt to be abnormal, showing cortical perfusion defects all on the side of the occlusion. Among these 17 patients, five demonstrated CCD. Four of these five CCD patients showed evidence for cerebral cortical ischaemia on the side of the temporary carotid occlusion either shortly after the procedure or following carotid artery sacrifice. Of the remaining 12 patients with regionally reduced cerebral perfusion and no CCD, none showed evidence for cortical ischaemia in association with balloon test occlusion, and five of these 12 patients had carotid ligation without subsequent neurologic sequelae.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Aged, 80 and over; Brain; Carotid Artery, Common; Carotid Artery, Internal; Catheterization; Cerebellar Diseases; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Predictive Value of Tests; Risk Factors; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Cerebral Infarction; Cysteine; Humans; Organotechnetium Compounds; Oximes; Radioactive Tracers; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Thallium-201 brain single-photon emission tomography (201Tl-SPET) is widely used to detect viable tumour tissue with increased metabolic activity. When reperfusion takes place early in cerebrovascular lesions of embolic origin, the presence of tissue areas with increased regional blood flow and preserved metabolic activity can also be assumed. In the present study our purpose was to investigate whether or not foci of 201Tl accumulation occur in reperfused areas with sustained morphological integrity indicated by computed tomography (CT) scans not showing hypodensity in the acute or subacute period. In 16 stroke patients with possible cortical embolic infarction, dual 201Tl and technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) SPET was performed in both the acute and the subacute period. 99mTc-HMPAO SPET was performed to detect reperfusion. Follow-up CT scans from the same period were also available. In five cases 99mTc-HMPAO SPET ruled out reperfusion and 201Tl SPET was also negative. In four cases 99mTc-HMPAO studies indicated reperfusion early in the acute phase (24-72 h), and comparative CT, without showing hypodensity in the acute or subacute period, also favoured the possibility of sustained metabolic activity. In these cases 201Tl SPET was negative in both the acute and the subacute period. In seven cases CT already showed necrosis in 99mTc-HMPAO hypoperfused areas in the acute period, with negative results on corresponding 201Tl SPET. Later reperfusion occurred in the subacute period (8-14 days) as indicated by 99mTc-HMPAO SPET, at which time an unexpected focal accumulation of 201Tl was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Cerebral Infarction; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Bilateral infarction in the anterior cerebral artery vascular territory is rare and usually results from rupture of an aneurysm of the anterior communicating artery. In the case of an anomaly of the anterior part of the circle of Willis, thrombosis also may lead to bilateral infarction.. A 73-year-old right-handed man presented with a complete loss of communicative behavior and an almost complete quadriplegia. 99mTc-hexamethylpropyleneamine oxime single-photon emission-computed tomography (HMPAO SPECT) of the brain showed a "horseshoe" image, reflecting bilateral perfusion defects in areas supplied by the anterior cerebral arteries. Postmortem examination of the brain revealed an unusual anomaly of the circle of Willis in which the postcommunicating part of the right anterior cerebral artery was absent.. In our patient a unique developmental anomaly of the circle of Willis indirectly contributed to bilateral infarction in the territory of the anterior cerebral artery. The patient's neuropsychological profile, dominated by akinetic mutism, was highly suggestive of involvement of the receptive language modalities. For the first time, 99mTc-HMPAO SPECT of the brain revealed a horseshoe image in bilateral infarction in the territory of the anterior cerebral artery.

Topics: Aged; Cerebral Arteries; Cerebral Infarction; Circle of Willis; Humans; Intracranial Embolism and Thrombosis; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To assess the clinical role of 99mTc-ethyl cysteinate dimer (ECD) as a cerebral perfusion tracer, 10 patients with unilateral cerebral infarction were studied.. ECD SPECT images were compared with IMP and/or HMPAO SPECT in nine patients, seven in chronic phases and two in subacute phases. Five of these patients and one additional patient with chronic infarction received PET imaging in order to compare ECD distribution with quantitative regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) images.. In patients with chronic cerebral infarction, regression analysis showed excellent correlation between ECD and IMP in the uptake ratio of lesions-to-nonaffected cortices (r = 0.91). In two cases of subacute infarction, decreased uptake of ECD was observed in the area of "luxury perfusion," which showed elevated or preserved rCBF with diminished rCMRO2. On visual analysis, ECD image contrast was less prominent compared to that of IMP, but contrast was better than that of HMPAO.. ECD uptake showed a curvilinear relationship against rCBF, suggesting flow-limited uptake in a high flow range. ECD is a clinically useful cerebral perfusion tracer with distinct characteristics when compared with other available agents.

Topics: Adult; Amphetamines; Brain; Cerebral Infarction; Cerebrovascular Circulation; Contrast Media; Cysteine; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; 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

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

In the period from October 1990 to December 1991, 23 patients with acute ischemic stroke were treated with recombinant tissue plasminogen activator (rt-PA) at a median of 205 min (range 78-355 min) after symptom onset. In this open pilot study rt-PA was given intravenously after an acute CT scan had not shown acute changes. In 12 patients regional cerebral blood flow was measured intravenously using 99mTc-HMPAO before and within 24 h after thrombolytic therapy. Reperfusion of the ischemic area was obtained in 10 patients. In these patients clinical improvement was greater the shorter the delay from symptom onset to initiation of treatment. Three of the 23 patients died, one of a parenchymatous hematoma, one of a large middle cerebral artery infarct, and one of acute myocardial infarction.

Topics: Cerebral Infarction; Denmark; Feasibility Studies; Humans; Intracranial Embolism and Thrombosis; Neurologic Examination; Organotechnetium Compounds; Oximes; Pilot Projects; Survival Rate; Technetium Tc 99m Exametazime; Thrombolytic Therapy; Tissue Plasminogen Activator; Tomography, Emission-Computed, Single-Photon

Double tracer autoradiography was performed to measure regional cerebral blood flow (rCBF) and the binding of central type benzodiazepine receptors (BZR) in infarction by means of permanent occlusion of the unilateral middle cerebral arteries (MCA) in rat. Iodine-125 Iomazenil and 99mTc-HMPAO was used to label BZR and rCBF respectively. In the chronic phase of infarction 21 to 28 days after occlusion (5 rats), rCBF in the left MCA territory was decreased to 62% of the sham control (4 rats), while BZR was more decreased to 45% of the control. In remote areas from the MCA lesion, the ipsilateral thalamus showed 28% decrease of BZR as compared to the control, though the decrease of rCBF was not significant. Iomazenil distribution may represent neuron density or BZR density on a neuron, since central type BZR is reported to be located on neurons. These results suggest that central type BZR imaging is more useful tool for the evaluation of brain tissue viability and transneuronal degeneration than rCBF imaging in brain infarction.

Topics: Animals; Autoradiography; Brain; Cerebral Infarction; Cerebrovascular Circulation; Chronic Disease; Flumazenil; Iodine Radioisotopes; Male; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Rats; Rats, Inbred Strains; Receptors, GABA-A; Technetium Tc 99m Exametazime

Attenuation coefficient maps (mu-maps) are a useful way to compensate for non-uniform attenuation when performing single photon emission tomography (SPET). A new method was developed to record single photon transmission data and a mu-map for the brain was produced using a four-head SPET scanner. Transmission data were acquired by a gamma camera opposite to a flood radioactive source attached to one of four gamma cameras in the four-head SPET scanner. Attenuation correction was performed using the iterative expectation maximization algorithm and the mu-map. Phantom studies demonstrated that this method could reconstruct the distribution of radioactivity more accurately than conventional methods, even for a severely non-uniform mu-map, and could improve the quality of SPET images. Clinical application to technetium-99m hexamethyl-propylene amine oxime (HMPAO) brain SPET also demonstrated the usefulness of this method. Thus, this method appears to be promising for improvement in the image quality and quantitative accuracy of brain SPET.

Topics: Adult; Algorithms; Brain; Cerebral Infarction; Humans; Image Processing, Computer-Assisted; Male; Models, Structural; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Cerebellar Diseases; Cerebral Infarction; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Cross-clamping of the carotid artery during carotid endarterectomy implies a risk of developing an ischaemic insult. To evaluate the effects of carotid artery occlusion on cerebral blood flow (CBF), both hemispheric and regional CBF (rCBF) were investigated using intravenously (i.v.) administered 133Xenon with 3 min clearance recording time for two-dimensionally (hemispheric CBF) and 99m-technetium-hexamethylpropylene amine oxime (99mTC-HMPAO) for three-dimensionally single photon emission computed tomography (SPECT) measurements (rCBF). Thirteen patients scheduled to undergo carotid endarterectomy anaesthetised with fentanyl/isoflurane participated in the study. Preoperative evaluation included investigation of rCBF with SPECT in all participants. Two intraoperative 133Xe CBF measurements were performed in each patient, before and after occlusion of the carotid artery. The preoperative rCBF measurement constituted the reference, for technical reasons, for the intraoperative investigations of rCBF during cross-clamping, which was completed immediately after the hemispheric measurements. The increase in preoperative risk evaluation as described by Sundt et al. and modified by Cho et al. corresponded excellently to a decrease in hemispheric CBF due to cross-clamping. A significant decrease in rCBF (p < 0.005) was present between patients with high and low preoperative risk score for the region of the middle cerebral artery. In this region, a correlation between decrease in rCBF and corresponding decrease in hemispheric CBF was also present. The present study demonstrates that the vascular regions of the ipsilateral middle cerebral artery are the most vulnerable vascular area during cross-clamping in individuals with high preoperative risk score.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Blood Flow Velocity; Brain; Brain Ischemia; Cerebral Infarction; Endarterectomy, Carotid; Female; Humans; Intraoperative Complications; Male; Middle Aged; Models, Theoretical; Monitoring, Intraoperative; Organotechnetium Compounds; Oximes; Regional Blood Flow; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

58 patients with recent transient or permanent neurologic deficits of with proven carotid stenoses were examined by dynamic CT at the level of the internal capsule. In the presence of cerebral infarcts there was marked delay in the time/density curve with reduced peaks. Abnormal perfusion could be demonstrated by early examinations before definite morphological changes were seen. With transient ischaemic attacks there were no significant changes in perfusion; in the presence of carotid stenoses the results were variable. The perfusion abnormalities in the hemispheres shown by dynamic cranial CT could be confirmed to some extent by 99mTc-HMPAO-SPECT.

Topics: Adult; Aged; Aged, 80 and over; Brain Ischemia; Cerebral Infarction; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Four patients with clinical signs of cerebellar stroke were studied twice by SPECT using 99mTc-HMPAO as a tracer for cerebral blood flow (CBF). When first scanned 6 to 22 days after onset, all had a region of very low CBF in the symptomatic cerebellar hemisphere, and a mild to moderate CBF reduction (average 10%) in contralateral hemispheric cortex. In all four cases clinical signs of unilateral cerebellar dysfunction were still present when rescanned 1 to 4 months later and the relative CBF decrease in the contralateral cortex of the forebrain also remained. The basal ganglia contralateral to the cerebellar lesion CBF showed variable alterations. A relative CBF decrease was seen in upper part of basal ganglia in all four cases, but it was not a constant phenomenon. A relative CBF increase in both early and late SPECT scans was seen at low levels of neostriatum in two cases. The remote CBF changes in cerebellar stroke seen in the forebrain are probably caused by reduced or abolished cerebellar output. The term "Crossed Cerebral Diaschisis" may be used to describe these CBF changes that would appear to reflect both decreased and increased neuronal activity.

Topics: Aged; Basal Ganglia Diseases; Cerebellar Diseases; Cerebellum; Cerebral Infarction; Cerebrovascular Circulation; Functional Laterality; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Cerebral Arteries; Cerebral Infarction; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vision Disorders

The previously reported method for quantitative measurements of whole-brain or hemispheric-brain perfusion using technetium-99m hexamethylpropylene amine oxime (HMPAO) radionuclide angiography is now further developed so that regional cerebral blood flow (rCBF) can be measured. Lassen's correction algorithm is used for the linearization of a curve-linear relationship between the radioactivity in the brain and blood flow as seen with single-photon emission tomography (SPET) images. In this algorithm, the cerebral hemisphere was chosen as the reference region and the correction factor alpha was adapted to rCBF in the reference region. This new method of measuring CBF from SPET has been validated in 33 normal subjects and 22 patients with cerebrovascular disease. Regional CBF values in 20 brain regions of the normal subjects were in good agreement with reported values measured by other methods. Regional CBF in the frontal cortex was greater than that in the temporal, parietal or occipital cortex for the entire age range. This hyperfrontal perfusion tended to be less pronounced with advancing age. Seventeen patients with unilateral brain infarction showed significantly lower rCBF than normal subjects. The infarct core showed a low rCBF value of 11.1 ml/100 g/min on average. An increase in rCBF after acetazolamide administration was observed and measured with this method in five patients with unilateral occlusive vascular pathology. These results suggest that this non-invasive method (without any blood sampling) permits the routine measurement of rCBF from HMPAO SPET tomograms of blood flow.

Topics: Acetazolamide; Algorithms; Brain; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Angiography; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The balloon occlusion test (BOT) of the internal carotid artery (ICA), combined with induced hypotension and cerebral blood flow (CBF) mapping, was carried out in three patients with a large or giant aneurysm of the ICA. Occlusion of the ICA for 10 minutes in the normotensive state was followed by 5 minutes of induced hypotension. During the last 2 minutes of hypotensive occlusion, technetium-99m-hexamethyl-propyleneamine oxime was administered to study the CBF. All patients tolerated the procedure well. One patient with moderate CBF reduction developed ischemic complications 24 hours after permanent ICA occlusion. Another showed no significant change in CBF and tolerated permanent ICA occlusion well, while the third refused permanent occlusion. The provocative BOT combined with CBF mapping is a promising predictor of complications of ICA occlusion secondary to perfusion abnormalities.

Topics: Aged; Algorithms; Aneurysm; Blood Pressure; Carotid Artery Diseases; Carotid Artery, Internal; Catheterization; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Hypotension, Controlled; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Topics: Adenoma, Acidophil; Aged; Cerebral Infarction; Humans; Male; Organotechnetium Compounds; Oximes; Pituitary Neoplasms; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The usefulness of a new cerebral perfusion imaging radiopharmaceutical, 99mTc-ethyl cysteinate dimer (ECD), was clinically evaluated. The subjects of this study were 14 patients with neurological disorders including 10 patients with cerebral infarction and 4 patients with other diseases. A total of 15 examinations was performed. 99mTc-HM-PAO or 123I-IMP SPECTs were performed simultaneously, and the findings from those examinations were compared with 99mTc-ECD. As to the count ratio of lesions to normal area (L/N), the L/N ratio in severe ischemic patients was lower in 99mTc-ECD than in 99mTc-HM-PAO or 123I-IMP. In mild ischemic patients, on the other hand, the L/N ratio was the lowest in 123I-IMP. When the relationship between rCBFs obtained from 123I-IMP and the values of L/N in 99mTc-ECD or 99mTc-HM-PAO was compared, the values of L/N in 99mTc-ECD or 99mTc-HM-PAO were found to have decreased linearity with increasing rCBF. In a patient showing luxury perfusion, the accumulation pattern of 99mTc-ECD was different from that of the other two radiopharmaceuticals, and focal defect was revealed in 99mTc-ECD SPECT. On the dynamic SPECT of 99mTc-ECD in a patient with meningioma, the tumor showed a change from high to low perfusion with the passage of time. This finding indicated that care should be taken in the evaluation of accumulation of 99mTc-ECD. Therefore, 99mTc-ECD was found to be useful as a cerebral perfusion agent. In addition, as accumulation of 99mTc-ECD might somehow reflect metabolism in some cases, further careful investigation of many cases should be carried out.

Topics: Adult; Aged; Amphetamines; Cerebral Infarction; Cysteine; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

99mTc-HMPAO crossed the blood brain barrier instantly in proportional to cerebral blood flow. Raise up stress and supine resting 99mTc-HMPAO with brain SPECT was devised for detecting abnormal response in the changes of cerebral perfusion pressure. Asymmetric ratio in the middle cerebral artery area in patients with internal carotid artery occlusion (n = 5) was changed significantly from 0.82 +/- 0.06 to 0.90 +/- 0.06 and that of normal (n = 5) was not changed from 0.94 +/- 0.03 to 0.95 +/- 0.01. Raise up 99mTc-HMPAO brain SPECT enhanced the detectability in abnormality of regional cerebral blood flow and visualized the dys-autoregulated area during blood pressure falls.

Topics: Blood Pressure; Brain; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Perfusion; Posture; Pressure; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The aim was to validate the MRI assessment of regional cerebral blood flow. Measurements were performed on a 1.5 T imaging system using a fast T2*-weighted gradient-echo sequence. After intravenous injection of gadolinium-DTPA 30 images were acquired in the same slice position during 84 seconds. In 12 volunteers we observed a symmetrical cortical decrease of signal intensity during the passage of the contrast medium. In 9/23 patients with impairment of cerebral blood flow a circumscribed area of reduced signal intensity decrease (hypoperfusion) was found. In 4/23 patients the decrease of signal intensity was more pronounced than in normals (hyperfusion). In 9/23 patients signal intensity changes were normal. HMPAO-SPECT confirmed successful MRI assessment of cerebral blood flow in 22/23 patients.

Topics: Cerebral Infarction; Cerebrovascular Circulation; Contrast Media; Gadolinium; Gadolinium DTPA; Humans; Injections, Intravenous; Magnetic Resonance Imaging; Organometallic Compounds; Organotechnetium Compounds; Oximes; Pentetic Acid; Prospective Studies; Reference Values; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Twenty-six patients with acute cerebral infarction were imaged by 99Tcm-hexamethylpropyleneamine oxime (HMPAO)-labelled white blood cell brain (Tc-WBC) single photon emission computed tomography (SPECT). The regions of interest were equally placed in the whole hemispheres of both sides with summation of all transaxial slices in the Tc-WBC SPECT. The asymmetric indices (AI) were calculated as 200[[(right - left)]/(right + left)]. Grouping of patients with cerebral infarction was based on activities of daily living (ADL) at outcome. The results showed that the poor outcome patient group had a higher AI of Tc-WBC than that of the other patients (13.0 +/- 3.0 S.E.M. versus 5.4 +/- 1.0 S.E.M., and P less than 0.05 by Wilcoxon rank sum test). In conclusion, the Tc-WBC SPECT may be considered as a new prognostic index to predict patient outcome in human cerebral ischaemic infarctions consistent with newly established ischaemic injury theories.

Topics: Acute Disease; Aged; Cerebral Infarction; Female; Humans; Leukocytes; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Acetazolamide; Adolescent; Adult; Aged; Brain; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Polyneuropathies; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We report on the use of Tc-99m hexamethylpropylene amineoxime (HMPAO) in watershed infarcts in five patients who had focal neurologic symptoms. Good correlation between Tc-99m HMPAO and CT was found in two patients. In three patients only Tc-99m HMPAO SPECT in a watershed distribution showed a perfusion abnormality that explained the clinical findings. Tc-99m HMPAO SPECT may be more sensitive than CT in the detection of infarctions in the watershed distribution.

Topics: Adult; Aged; Aged, 80 and over; Brain; Cerebral Infarction; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Using SPECT, the time course of brain uptake was compared between N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) and Tc-99m d,l hexamethyl-propyleneamine oxime (Tc-99m HM-PAO). Of 14 patients with cerebrovascular disease showing areas of the "filling-in phenomenon" (i.e. delayed uptake) with I-123 IMP brain SPECT, 7 exhibited persistent defects with Tc-99m HM-PAO (Group I), and 7 showed early washout after the initial uptake (Group II). The filling-in of I-123 IMP did not always correlate to the washout region of Tc-99m HM-PAO. The temporal changes were also confirmed by semiquantitative analysis. While the filling-in of I-123 IMP was affected by many factors, the washout of Tc-99m HM-PAO was attributed to significant reduction of Tc-99m HM-PAO in the plasma. Delayed imaging of the brain with Tc-99m HM-PAO using SPECT may give a more accurate estimate of regional cerebral blood flow in cerebrovascular disease, because it should be lees effected by cerebral blood volume.

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

The annular single-crystal brain camera (ASPECT) is a digital SPECT system with a single-crystal sodium iodide thallium Nal(Tl) ring detector and collimator system designed to view the patient's head from three angles simultaneously. The ring is rotated concentrically to the detector for three-dimensional reconstruction over a 21.4 cm (diameter) by 10.7 cm (length) field of view. We evaluated the system clinically by imaging a Hoffman brain phantom and seven subjects, of whom two were normal controls, three had previous cerebral infarction and two had dementia. The ASPECT system produced tomographic images of high spatial resolution. In normal subjects, the separation of striata from thalami by the posterior limbs of the internal capsules was much clearer on ASPECT images than on rotating gamma camera images. The high spatial resolution obtained with the ASPECT system translates into superior anatomical representation of the brain compared to the standard rotating gamma camera.

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

Topics: Acute Disease; Blood-Brain Barrier; Cerebral Infarction; Cerebrovascular Circulation; Humans; Organometallic Compounds; Oximes; Prognosis; Radionuclide Imaging; Technetium Tc 99m Exametazime

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

Topics: Aged; Cerebral Infarction; Female; Humans; Male; Organometallic Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Acute Disease; Aged; Brain; Brain Ischemia; Cerebral Cortex; Cerebral Infarction; Female; Follow-Up Studies; Humans; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prospective Studies; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

The results of previous reports on the usefulness of brain perfusion single photon emission computed tomography (SPECT) in predicting the outcome of patients with acute cerebral infarction are conflicting. We therefore studied brain perfusion in 64 patients with a single supratentorial infarction. Contradictory to previous results the perfusion defect volume estimated from transversal and coronal slices correlated significantly with both presenting clinical findings and outcome. Although the clinical status at admission also correlated well with outcome, there was a subgroup of patients in which the favourable outcome was predicted only by SPECT and not by physical or any other examination at admission.

Topics: Adult; Aged; Amphetamines; Brain; Cerebral Infarction; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Aged; Cerebral Infarction; Erythrocytes; Humans; Intracranial Arteriovenous Malformations; Male; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Aged; Amphetamines; Brain; Cerebral Infarction; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed

A combined measurement of regional cerebral blood flow (r CBF) and volume (r CBV) by SPECT was performed in 15 patients with ischaemic cerebral infarction. For measurement of r CBF 99mTc-HMPAO was used, and for r CBV 99mTc-labelled red blood cells. Patients with acute or subacute cerebral infarction (n = 10) showed elevation of r CBV whereas r CBF was either reduced or elevated. Patients with chronic cerebral infarction (n = 5) showed reduction of both r CBF and r CBV. The combined measurement of both r CBF and r CBV by SPECT allows imaging and semiquantitative evaluation of haemodynamic changes in ischaemic cerebral infarction at various stages. The resulting data may be helpful in describing the pathophysiologic compensatory mechanisms.

Topics: Aged; Aged, 80 and over; Blood Volume; Blood Volume Determination; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; Humans; Middle Aged; Organometallic Compounds; Oximes; Sodium Pertechnetate Tc 99m; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

A new cerebral blood flow agent, 99Tcm-hexamethylpropyleneamine oxime (HM-PAO), was evaluated for early detection of acute cerebral infarction in conjunction with the transmission computed tomographic (CT) studies. The data from 22 cases were analysed. Results reveal that 99Tcm-HM-PAO enables the early detection of acute cerebral infarction prior to CT with rather proper depiction of the extent of physiological abnormality in the majority of patients. This promising result together with the lack of logistical problems will make 99Tcm-HM-PAO a useful and practical agent worldwide for diagnosing and managing acute cerebral infarction.

Topics: Brain; Cerebral Infarction; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed

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