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

The purpose of this atlas is to present a review of the literature showing the advantages of SPECT brain perfusion imaging (BPI) in mild or moderate traumatic brain injury (TBI) over other morphologic imaging modalities such as x-ray CT or MRI. The authors also present the technical recommendations for SPECT brain perfusion currently practiced at their center. For the radiopharmaceutical of choice, a comparison between early and delayed images using Tc-99m HMPAO and Tc-99m ECD showed that Tc-99m HMPAO is more stable in the brain with no washout over time. Therefore, the authors feel that Tc-99m HMPAO is preferable to Tc-99m ECD. Recommendations regarding standardizing intravenous injection, the acquisition, processing parameters, and interpretation of scans using a ten grade color scale, and use of the cerebellum as the reference organ are presented. SPECT images of 228 patients (age range, 11 to 88; mean, 40.8 years) with mild or moderate TBI and no significant medical history that interfered with the results of the SPECT BP were reviewed. The etiology of the trauma was in the following order of frequency: motor vehicle accidents (45%) followed by blow to the head (36%) and a fall (19%). Frequency of the symptoms was headache (60.9%), memory problems (27.6%), dizziness (26.7%), and sleep disorders (8.7%). Comparison between patients imaged early (<3 months) versus those imaged delayed (>3 months) from the time of the accident, showed that early imaging detected more lesions (4.2 abnormal lesions per study compared to 2.7 in those imaged more than 3 months after the accident). Of 41 patients who had mild traumatic injury without loss of consciousness and had normal CT, 28 studies were abnormal. Focal areas of hypoperfusion were seen in 77% (176 patients, 612 lesions) of the group of 228 patients. The sites of abnormalities were in the following order: basal ganglia and thalami, 55.2%, frontal lobes, 23.8%, temporal lobes, 13%, parietal, 3.7%, insular and occipital lobes together, 4.6%.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Basal Ganglia; Brain Injuries; Cerebrovascular Circulation; Child; Cysteine; Dizziness; Frontal Lobe; Headache; Humans; Image Processing, Computer-Assisted; Injections, Intravenous; Magnetic Resonance Imaging; Memory Disorders; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Thalamus; Time Factors; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Unconsciousness

The development of cholinergic therapies for Alzheimer's disease (AD) has highlighted the importance of understanding the role of attentional deficits and the relationship between attention and memory in the earliest stages of the disease. Variability in the tasks used to examine aspects of attention, and in the disease severity, between studies makes it difficult to determine which aspects of attention are affected earliest in AD, and how attentional impairment is related to other cognitive modules. We tested 27 patients in the early stages of the disease on the basis of the MMSE (minimal 24-30 corresponding to minimal cognitive impairment, very mild or possible AD in other classifications; and mild 18-23) on a battery of attentional tests aimed to assess sustained, divided, and selective attention, plus tests of episodic memory, semantic memory, visuoperceptual and visuospatial function, and verbal short-term memory. Although the mildly demented group were impaired on all attentional tests, the minimally impaired group showed a preserved ability to sustain attention, and to divide attention based on a dual-task paradigm. The minimally demented group had particular problems with response inhibition and speed of attentional switching. Examination of the relationship between attention and other cognitive domains showed impaired episodic memory in all patients. Deficits in attention were more prevalent than deficits in semantic memory suggesting that they occur at an earlier stage and the two were partially independent. Impairment in visuoperceptual and visuospatial functions and verbal short-term memory were the least common. Although attention is impaired early in AD, 40% of our patients showed deficits in episodic memory alone, confirming that amnesia may be the only cognitive deficit in the earliest stages of sporadic AD.

Topics: Aged; Alzheimer Disease; Attention; Disease Progression; Female; Follow-Up Studies; Humans; Intelligence Tests; Male; Memory Disorders; Neuropsychological Tests; Psychomotor Performance; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To determine if hypoperfusion abnormalities on single photon emission computed tomography (SPECT) are associated with poorer cognitive function at baseline or increased risk of decline in cognitive function and progression to dementia in memory-impaired but non-demented elderly subjects meeting the criteria for aging associated cognitive decline (AACD).. Cross sectional study of 36 AACD subjects comparing hexamethyl propylene-amine oxime (HMPAO) SPECT results rated by visual inspection with base line cognitive functioning. Prospective study of these AACD subjects with clinical and neuropsychological follow-up over 35 months.. The memory clinic and nuclear medicine unit of a university teaching hospital.. Thirty-six subjects meeting the criteria for AACD recruited from patients seen on a physician referral basis.. 1) Baseline cognitive function as measured by the Mini Mental State Examination (MMSE), Boston naming, Logical Memory I subtest of the WAIS-R, and verbal fluency, correlated with SPECT status. 2) Decline in cognitive function as measured by clinical exam and the MMSE, with progression to dementia on follow-up being correlated with SPECT status at baseline.. 18 of the 36 subjects progressed to dementia (probable Alzheimer's Disease) over follow-up. No correlation was found between the presence or absence of SPECT abnormality and MMSE or other cognitive measures. There was no correlation between the presence or absence of SPECT abnormality at initial examination, and cognitive decline according to the MMSE, or with the occurrence of clinical dementia on follow-up.. We conclude that SPECT abnormalities assessed by visual inspection do not correlate with severity of impairment in AACD individuals, and are not useful in predicting progression to dementia in AACD subjects.

Topics: Aged; Aged, 80 and over; Cognition Disorders; Cross-Sectional Studies; Female; Follow-Up Studies; Humans; Male; Memory Disorders; Middle Aged; Neuropsychological Tests; Prognosis; Prospective Studies; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Two radiopharmaceuticals, 99Tcm-hexamethyl propylene amine oxime (99Tcm-HMPAO) and 99Tcm-ethyl cysteinate dimer (99Tcm-ECD), are currently used to determine cerebral blood flow. 99Tcm-ECD is, by virtue of its greater stability, superseding 99Tcm-HMPAO for routine examinations. Since the clinical assessment of 99Tcm-ECD images is usually based on experience with 99Tcm-HMPAO, we used both radiopharmaceuticals to compare regional cerebral blood flow in the same individuals. Eleven healthy subjects aged 67.1 +/- 6.3 years (mean +/- S.D.) underwent 99Tcm-ECD followed by 99Tcm-HMPAO single photon emission tomography. Cerebral blood flow was quantified in cortical and central regions of interest (basal ganglia, ventricles, white matter) in relation to cerebellar uptake. The intra-subject comparison of cerebral blood flow in the cortical areas revealed higher levels of perfusion in the posterior parietal, parieto-occipital and temporo-occipital areas using 99Tcm-ECD. In contrast to the cortical areas, cerebral blood flow in the central areas was greater using 99Tcm-HMPAO, especially in the centrum semiovale, basal ganglia, frontal white matter and frontal horns. This difference in cerebral blood flow when imaging healthy individuals with 99Tcm-ECD and 99Tcm-HMPAO should be taken into account in clinical practice when changing from one radiopharmaceutical to the other.

Topics: Aged; Brain; Cerebrovascular Circulation; Cysteine; Female; Humans; Male; Memory Disorders; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Reference Values; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Xenon Radioisotopes

Alzheimer's disease (AD) and frontotemporal dementia (FTD) are the most common types of dementia in the presenile population. Episodic memory impairment, the clinical hallmark of AD, can also be encountered in patients with FTD, complicating accurate diagnosis. Several studies in FTD have correlated memory deficits with neuroimaging findings, but lacked to compare neuroimaging results in FTD patients with and without memory impairment, while this latter analysis may give us insight into the underlying mechanisms of memory impairment in FTD. The aim of the present study was to compare (99m)Tc-HMPAO SPECT hypoperfusion patterns between FTD with episodic memory impairment (n = 13), FTD patients without episodic memory impairment (n = 10) as well as early onset (< 70 yrs) AD patients (n = 13), and controls (n = 15). We performed our analyses by means of Statistical Parametric Mapping software (SPM5), and showed that FTD patients with episodic memory impairment had lower perfusion in the right temporal lobe compared with FTD patients without memory impairment. Lower perfusion in this region correlated with worse memory performance on the Clinical Dementia Rating scale in FTD patients. With equal performances on memory tests, patients with early onset AD showed posterior temporal and parietal lobe hypoperfusion in comparison with patients with FTD and memory impairment, while vice versa hypoperfusion in the anterior frontotemporal regions was found in FTD patients with memory impairment in comparison with AD.

Topics: Alzheimer Disease; Female; Frontotemporal Dementia; Humans; Male; Memory Disorders; Memory, Episodic; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Frontotemporal lobar degeneration (FTLD) is a clinically, genetically, and pathologically heterogeneous disorder. The aim of this study was to compare clinical features and perfusion patterns on SPECT of patients with familial FTLD-TAR DNA binding protein 43 kDa (TDP) and MAPT mutations.. Patients were included if they had MAPT or GRN mutations, positive family history with pathologically proven FTLD in the patient or first-degree relative, or were part of FTD-MND families. All patients and 10 age- and gender-matched controls underwent measurement of brain perfusion using (99m)Tc-HMPAO SPECT. We used SPM8 to perform image processing and voxel-based group analyses (p < 0.001). Gender and age were included as nuisance variables in the design matrices.. Of the 29 patients with familial FTLD, 19 had familial FTLD-TDP (GRN mutations in 6), and 10 had MAPT mutations. At clinical presentation, familial FTLD-TDP patients were older at onset (p = 0.030) and had more memory deficits (p = 0.011), whereas patients with MAPT had more naming deficits (p < 0.001) and obsessive-compulsive behavior (p = 0.001). The between-groups SPECT analyses revealed significantly less perfusion in the right frontal lobe, precuneus, cuneus, and inferior parietal lobule in familial FTLD-TDP, whereas significantly less perfusion was found in the left temporal and inferior frontal gyri in MAPT. Post hoc analysis of familial FTLD-TDP with unknown genetic defect vs MAPT revealed less perfusion in the right frontal and parietal lobe.. Familial FTLD-TDP shows relatively more posterior hypoperfusion, including the precuneus and inferior parietal lobule, possibly related to significant memory impairment. Patients with MAPT were characterized by impaired perfusion of the temporal regions and naming deficits.

Topics: Brain; DNA-Binding Proteins; Female; Frontotemporal Lobar Degeneration; Humans; Intercellular Signaling Peptides and Proteins; Male; Memory Disorders; Middle Aged; Mutation; Neuropsychological Tests; Obsessive-Compulsive Disorder; Progranulins; tau Proteins; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The aim of this article is to compare patients with Alzheimer's disease (AD) pathology and corticobasal degeneration pathology (CBD) presenting as corticobasal syndrome (CBS). Clinicopathologic series was used. Five patients with AD and 11 patients with CBD were clinically diagnosed with CBS. Patients with AD pathology had an earlier age of onset than patients with CBD pathology (58 vs. 68 years, P = 0.004), but the two groups had similar disease duration and core features of CBS. Tremors were only present in CBD cases (73%, P = 0.026), but myoclonus was more common in AD than CBD (80 vs. 18%, P = 0.036). Neuropsychological testing showed similar degrees of memory impairment and attentional deficits. (99m)Tc-HMPAO SPECT imaging demonstrated parietal hypoperfusion in AD patients and frontotemporal hypoperfusion in CBD patients. AD patients with clinical CBS have similar characteristics to CBD patients. Functional brain imaging may have greater utility than the clinical and neuropsychological features in differentiating AD presenting as CBS from CBD.

Topics: Aged; Alzheimer Disease; Autopsy; Basal Ganglia; Cerebral Cortex; Female; Humans; Male; Memory Disorders; Middle Aged; Neurodegenerative Diseases; Neuropsychological Tests; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To determine and correlate alterations in neuropsychological function and cerebral blood flow in bipolar patients.. Assessments included the Positive and Negative Symptom Scale, Global Assessment Functioning, Wechsler Adult Intelligence Scale (WAIS), Wisconsin Card Sorting Test (WCST), Stroop test, Trail Making Test (TMT), California Verbal Learning Test (CVLT), Wechsler Memory Scale (WMS) and phonetic verbal fluency/controlled oral word association tests. Single photon emission computed tomography (SPECT) was carried out with the administration of 99mTc-HMPAO. Forty-three outpatients out of 85 fulfilling RDC diagnostic criteria for bipolar disorder and six healthy subjects were included in the study. SPECT and neuropsychological assessments were performed in 30 patients in manic (n = 7), hypomanic (n = 8), depressed (n = 12) or euthymic (n = 3) states. All assessments were carried out before starting treatment.. Several corrected correlations between neuropsychological function and cerebral blood flow (CBF) were identified: executive function (WCST) and striatal, frontal, temporal, cerebellum, parietal and cingulate CBF; memory (WMS, WAIS-Digits) and striatal, frontal, temporal and parietal CBF; attentional tasks (Stroop) and striatal, temporo-medial and parietal CBF; verbal learning (CVLT) and frontal, posterior temporal, cingulate and occipital CBF; psychomotor disturbances (TMT) and anterior temporal CBF; poorer intelligence performance scores (WAIS-Vocabulary) and cerebellum and parietal CBF.. This study confirms the presence of functional disturbances in fronto-subcortical structures, the cerebellum and limbic system in bipolar patients.

Topics: Adult; Bipolar Disorder; Brain; Cerebrovascular Circulation; Cognition Disorders; Female; Humans; Male; Memory Disorders; Psychomotor Disorders; Radiopharmaceuticals; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Wechsler Scales

To identify group differences in the prodromal phase of Alzheimer disease (AD) using quantitative single-photon emission computed tomography (SPECT) perfusion and magnetic resonance imaging (MRI) volume measures within specific volumes of interest.. Gerontology research unit.. There were 17 healthy controls, 56 nondemented patients with memory problems who did not develop AD during 3 to 5 years of follow-up (questionables), and 27 nondemented patients with memory problems who developed AD during follow-up (converters).. A Tc 99m hexamethylpropyleneamine oxime SPECT study and an MRI were performed in each participant at baseline. Mean SPECT activity concentration and MRI volume were estimated within 9 structures: rostral anterior cingulate, caudal anterior cingulate, posterior cingulate, hippocampus, entorhinal cortex, basal forebrain, temporal horn, amygdala, and the banks of the superior temporal sulcus. Data were analyzed using overall and pairwise discriminant analysis, and performance in pairwise group discrimination was measured using correlated receiver operating characteristic curve analysis.. The overall (3-group) discriminant function was significant for SPECT (F test, P<.001) and MRI (F test, P<.0001). For the SPECT analysis, the ranking of structures for discriminating among the 3 groups was, in order of decreasing discriminating power, caudal anterior cingulate, temporal horn, superior temporal sulcus, entorhinal cortex, hippocampus, rostral anterior cingulate, amygdala, basal forebrain, and posterior cingulate. For the MRI analysis, this ranking was entorhinal cortex, superior temporal sulcus, temporal horn, hippocampus, amygdala, caudal anterior cingulate, rostral anterior cingulate, basal forebrain, and posterior cingulate. Combining the 2 modalities yielded significantly better discrimination performance than did either alone. Furthermore, the correlation between SPECT and MRI measures was low.. Measures of structure activity concentration and volume carry independent information; both reveal group differences in prodromal AD.

Topics: Aged; Alzheimer Disease; Brain; Humans; Magnetic Resonance Imaging; Memory Disorders; Predictive Value of Tests; Radiography; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The purpose of the present study was to evaluate neuropsychological performance and regional cerebral blood flow in migraine patients, and to investigate whether possible abnormalities in any of these fields could be related to the chronicity of the disease. The sample included 60 patients and 30 healthy control subjects; all of them were subjected to a complete neuropsychological assessment, including emotional variables. In addition an interictal 99Tc-HMPAO SPECT was performed in 56 patients and 15 controls. Disturbances in memory, attention and visuomotor speed processing were observed among migraineurs experiencing higher frequency of attacks and in those with a long history of migraine. Anxiety levels were higher in patients than in controls and were positively correlated with attack frequency, but not with cognitive test scores. Brain perfusion abnormalities, mostly hypoperfusion areas, were found in the 43% of patients; poorer performance in two tests, measuring verbal and visual memory, respectively, was found in these patients.

Topics: Adolescent; Adult; Aged; Anxiety; Attention; Brain; Cerebrovascular Circulation; Cognition Disorders; Female; Humans; Male; Memory Disorders; Middle Aged; Migraine Disorders; Neuropsychological Tests; Psychomotor Performance; Reaction Time; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Inadequate sodium amytal delivery to the posterior hippocampus during the intracarotid Wada test has led to development of selective tests. Our purpose was to show the sodium amytal distribution in the posterior cerebral artery (PCA) Wada test and to relate it to functional deficits during the test. We simultaneously injected 80 mg sodium amytal and 14.8 MBq 99mTc-hexamethylpropyleneamine oxime (HMPAO) into the P2-segment of the PCA in 14 patients with temporal lobe epilepsy. To show the skull, we injected 116 MBq 99mTc-HDP intravenously. Sodium amytal distribution was determined by high-resolution single-photon emission computed tomography (SPECT). In all patients, HMPAO was distributed throughout the parahippocampal gyrus and hippocampus; it was also seen in the occipital lobe in all cases and in the thalamus in 11. Eleven patients were awake and cooperative; one was slightly uncooperative due to speech comprehension difficulties and perseveration. All patients showed contralateral hemianopia during the test. Four patients had nominal dysphasia for 1-3 min. None developed motor deficits or had permanent neurological deficits. Neurological deficits due to inactivation of extrahippocampal areas thus do not grossly interfere with neuropsychological testing during the test.

Topics: Adult; Amobarbital; Aphasia; Brain; Epilepsy, Temporal Lobe; Female; Hemianopsia; Humans; Injections, Intra-Arterial; Male; Memory; Memory Disorders; Middle Aged; Posterior Cerebral Artery; Postoperative Complications; Psychomotor Performance; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To examine the role of structural (magnetic resonance imaging [MRI]) and functional (single photon emission computed tomography [SPECT]) imaging and neuropsychologic evaluation in the early diagnosis of frontal variant frontotemporal dementia (fvFTD).. Current criteria for FTD stress the need for neuropsychologic and functional neuroimaging abnormalities, yet caregivers report lengthy histories of behavioral change. It is not known when, in the course of the disease, these investigations become abnormal, because few longitudinal studies have been reported.. Longitudinal study of two patients with serial neuropsychologic evaluation and MRI and HMPAO-SPECT scanning.. Both patients, men aged 49 and 50, had major changes in personality, behavior, and social conduct that progressed over 5 to 6 years in a way that conformed to the clinical picture of fvFTD. There was remarkably little abnormality on neuropsychologic testing, and MRI and HMPAO-SPECT findings initially were normal. Over time, however, abnormalities on SPECT, frontal atrophy on MRI, or a neuropsychologic profile more typical of fvFTD developed in both patients.. Standard neuropsychologic tests and conventional brain imaging techniques (MRI and SPECT) may not be sensitive to the early changes in fvFTD that occur in the ventromedial frontal cortex, and better methods of accurate early detection are required. These findings are relevant to the diagnostic criteria for FTD.

Topics: Atrophy; Chronic Disease; Cognition Disorders; Dementia; Disease Progression; Frontal Lobe; Humans; Irritable Mood; Longitudinal Studies; Magnetic Resonance Imaging; Male; Memory Disorders; Middle Aged; Neuropsychological Tests; Personality Disorders; Sensitivity and Specificity; Social Behavior Disorders; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Thirty-four patients with a probable Alzheimer's Disease (AD) (mild AD = 16; moderate AD = 18) and 12 matched controls were evaluated using semiquantitative SPECT-99mTc-HMPAO and neuropsychological tests (CERAD).. Both temporal hypoperfusion (p < 0.01) and memory tests (p < 0.001) made it possible to differentiate the controls from mild AD patients. In these patients, significant correlations (p < 0.05) were also found between: 1) delayed recall test/temporal hypoperfusion, 2) learning memory test/temporoparietal and frontal hypoperfusion and 3) visual constructive praxis/posterior temporal hypoperfusion. In contrast to mild AD, moderate AD patients showed higher temporal (p < 0.01) parietal and frontal (p < 0.05) hypoperfusion along with worsening of praxis (p < 0.001) and memory tests (p < 0.05).. SPECT imaging and neuropsychology evaluation can distinguish controls from AD patients with mild an moderate grades of dementia, showing a strong correlation from the early stages of AD.

Topics: Aged; Alzheimer Disease; Brain; Cerebrovascular Circulation; Dementia; Diagnosis, Differential; Female; Humans; Male; Memory Disorders; Middle Aged; Neuropsychological Tests; Sensitivity and Specificity; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Hippocampal damage has been linked to memory impairment. To clarify the relationship between decreased hippocampal blood flow and memory impairment in patients after cardiovascular surgery, the authors compared Tc-99m HMPAO SPECT findings and Mini Mental State Examination (MMSE) scores. Eight patients who had valve replacement, two who underwent aorto-coronary bypass, two who had aortic aneurysm replacement and one who had a ventricular septal defect closure were included in this study. Cerebral perfusion was estimated using reconstructed tomographic images, which were parallel to the longitudinal axis of the hippocampal formations. The hippocampal uptake ratios of Tc-99m HMPAO were calculated and normalized to that of the cerebellum. In three patients whose MMSE score decreased after surgery, the hippocampal uptake ratio was significantly reduced (0.69 +/- 0.09) compared with the remaining 10 patients whose MMSE scores did not decrease after surgery (0.91 +/- 0.02). These data suggest that SPECT imaging parallel to the longitudinal axis of the hippocampus is sensitive to decreased hippocampal blood flow, and decreased hippocampal blood flow is related to memory impairment in some patients after cardiovascular surgery.

Topics: Adolescent; Adult; Aged; Cardiovascular Surgical Procedures; Cerebrovascular Circulation; Female; Hippocampus; Humans; Male; Memory Disorders; Mental Status Schedule; Middle Aged; Postoperative Complications; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A 49-year-old man was admitted to our hospital because of epileptic seizures and memory dysfunction. He had been experiencing seizures several times a day since the age of 43 years. Despite antiepileptic drug therapy (sodium valproate [VPA] and clonazepam [CZP], he suffered from frequent complex partial seizures originating in the temporal lobe, and he had a memory disturbance since age 47. When carbamazepine (CBZ) was substituted for VPA and CZP, the epileptic seizures stopped and the memory disturbance improved. Noninvasive regional cerebral blood flow (rCBF) measurements using 99mTc-HMPAO-SPECT imaging were performed twice. The initial measurements on admission showed overall decreased rCBP that was more prominent in the cerebral cortex than in the subcortical nuclei. A follow-up SPECT examination after clinical improvement revealed a marked overall increase in rCBF, especially in the cerebral cortex. The SPECT findings suggest that the memory disturbance in this patient may have been associated with the overall cerebral blood hypoperfusion. This overall hypoperfusion can be attributed to the frequent complex partial seizures and/or the adverse effect of VPA and CZP. SPECT can provide important information suggesting the pathogenesis of memory disturbance associated with epilepsy.

Topics: Anticonvulsants; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Humans; Magnetic Resonance Imaging; Male; Memory Disorders; Middle Aged; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To better understand how to differentiate the "in vivo" normal aging brain from pathological conditions, namely dementia of the Alzheimer type (DAT), by means of magnetic resonance imaging (MRI), single photon emission computerized tomography (SPECT), and proton magnetic resonance spectroscopy (1H-MRS), to show neuroanatomical, perfusional and neurochemical details, respectively.. 1H-MRS, MRI-based hippocampal volumetry and 99mTc-HMPAO SPECT were performed in healthy older subjects as well as patients suffering from age-associated memory impairment (AAMI) and dementia of Alzheimer type (DAT).. Eighteen subjects were selected from those referred to an outpatient clinic for diagnostic evaluation of cognitive impairment entered the study. Six patients fulfilled NINCDS-ADRDA diagnostic criteria for DAT, six subjects were affected by AAMI, and six cognitively healthy subjects, selected from among relatives of the patients, were defined as controls.. The 1H-MRS and MRI studies were performed on a 1.5 Tesla NMR-imaging system equipped with a spectroscopy research package. SPECT scans were performed on a Gamma 11 computer system.. 1H-MRS showed significantly lower N-acetylasparatate concentration in DAT and AAMI compared with controls. Conversely, mean inositol concentration was significantly higher in DAT than in controls, whereas AAMI subjects registered intermediate values. MRI measurements showed significantly reduced volumes of hippocampal formations in DAT and AAMI groups compared with controls. Finally, 99mTc-HMPAO SPECT showed a significant frontal, temporo-parietal, and occipital hypoperfusion in DAT patients only.. These findings support the hypothesis of a continuum among the three conditions studied, or at least between AAMI and DAT, where AAMI seems to be an early, monosymptomatic stage of Alzheimer disease. Accepting this view, it would be questionable to maintain the term "age-associated memory impairment" as a discrete entity.

Topics: Aged; Aged, 80 and over; Aging; Alzheimer Disease; Aspartic Acid; Brain Chemistry; Case-Control Studies; Diagnosis, Differential; Female; Hippocampus; Humans; Inositol; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Memory Disorders; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The value of hexamethylpropyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) as a diagnostic test for Alzheimer's disease (AD) was assessed in 44 patients attending a Memory Clinic. A comprehensive physical and psychiatric examination and detailed neuropsychological tests were used to arrive at a clinical diagnosis, in accordance with NINCDS-ADRDA criteria. The mean patient age was 69 (range 59-84) years, and the mean score on the Mini-Mental State Examination (MMSE) was 24 (range 7-30). Of 26 patients with a clinical diagnosis of AD, only 15 demonstrated a scan pattern strongly suggestive of AD. Four scans were normal, four showed evidence of ischaemic change and three were in the category 'other', one of which showed bilateral frontal hypoperfusion, but normal temporoparietal flow. Of the eight patients considered by clinical criteria to be non-demented, no scan showed an AD pattern, but three showed an ischaemic pattern. Both of the patients diagnosed clinically as suffering from multi-infarct dementia showed SPECT scan evidence of ischaemic change. Of the remaining eight patients with other clinical diagnoses only one scan suggested AD. We conclude that the HMPAO SPECT scan appearances which arise from AD in the early stages of the disease do not on their own allow the disease to be accurately diagnosed, but they may be useful if interpreted in conjunction with other imaging techniques.

Topics: Aged; Alzheimer Disease; Brain; Female; Geriatric Assessment; Humans; Male; Memory Disorders; Organotechnetium Compounds; Outpatient Clinics, Hospital; Oximes; Referral and Consultation; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To better identify regions of the brain affected by intracarotid amobarbital injections and to more precisely predict whether resections of specific brain regions will cause postoperative memory deficits.. We modified the standard intracarotid amobarbital procedure by adding a radioactive tracer to the amobarbital injection, thereby providing better correlation between behavior and deactivated brain region.. Tertiary-care hospital center with a dedicated program for medical and surgical treatment of epilepsy.. We studied 39 patients with medically intractable epilepsy drawn from a regional referral base.. Intracarotid injection of 125 mg of sodium amobarbital with 37 MBq of technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO), followed by language and memory testing.. The distribution of amobarbital as measured by single photon emission computed tomographic imaging of HMPAO and patient performance on memory tasks.. Medial temporal regions were irrigated by the amobarbital in only 28% of the injections. Overall, findings suggest that medial temporal and lateral neotemporal cortex play a role in memory.. The regions involved in memory function vary by individual, as does the distribution of amobarbital. Thus, the most accurate method of determining correlation of brain region with memory function during intracarotid amobarbital injection involves the use of a tracer such as HMPAO.

Topics: Adolescent; Adult; Amobarbital; Brain; Carotid Arteries; Cerebrovascular Circulation; Epilepsy; Female; Humans; Injections; Male; Memory Disorders; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Radionuclide Imaging; Technetium Tc 99m Exametazime; Temporal Lobe

The aim of the present study was to see whether HMPAO-SPECT may contribute to the differentiation between dementia of the Alzheimer type (DAT) and major depression (MD). The results in 77 patients with memory impairment were evaluated. 48 patients suffered from DAT and 29 from MD. Initially, the defects in SPECT imaging were attributed to a cerebral region and the degree of decrease was evaluated (-1/-2/-3). Thereafter, the results were classified by 7 categories. In some of these categories an accumulation of cases of either DAT or MD was found. 35% of the patients suffering from DAT had bilateral defects with distinct (> -1) parietal/parietotemporal hypoperfusions, but no patient with MD showed this perfusion pattern. 62% of the patients with MD had unilateral defects but only 31% of the patients with DAT. The present study demonstrates that only 35% of all patients suffering from DAT show a perfusion pattern, thought earlier as "pathognomonic" for this disease. This perfusion pattern--if it exists--may be used as a safe criterion to exclude MD. Beyond that no clearcut ("specific") perfusion pattern may be recognized but unilateral defects point to MD.

Topics: Aged; Alzheimer Disease; Depressive Disorder; Female; Humans; Male; Memory Disorders; Organotechnetium Compounds; Oximes; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A 32-year old woman presented with serious memory impairment and a mental syndrome named loss of psychic auto-activation or psychic akinesia following carbon monoxide poisoning. The MRI findings were bilateral pallidal lesions probably associated with thalamic lesions. The evolution was favourable.

Topics: Adult; Brain; Carbon Monoxide Poisoning; Electroencephalography; Female; Humans; Magnetic Resonance Imaging; Memory Disorders; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Substance-Related Disorders; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Technetium (99mTc) hexamethyl propylene amine oxime (HM-PAO) was injected into the internal carotid artery in ten epileptic patients after the end of amobarbital speech-memory tests. The cerebral perfusion as visualized from SPET was compared to cerebral angiographies, which showed unilateral filling of intracranial vessels in seven patients. SPET revealed cross-flow between the hemispheres in four of these seven patients. In three patients in whom the angiograms had shown bilateral contrast filling, SPET showed cross-flow in only two. It is concluded that 99mTc-HM-PAO SPET examinations provide valuable information for correct interpretation of amobarbital tests on cognitive hemisphere functions. The SPET technique may help to explain atypical speech and memory responses caused by unusual intracranial vascularization.

Topics: Adult; Amobarbital; Brain; Carotid Artery, Internal; Cerebral Angiography; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Humans; Injections, Intra-Arterial; Male; Memory Disorders; Organotechnetium Compounds; Oximes; Speech Disorders; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon