Regional Cerebral Blood Flow Deficits Research Articles

A serial study of regional cerebral blood flow deficits in patients with left anterior thalamic infarction: Anatomical and neuropsychological correlates

Thalamic damage is associated with a variety of neuropsychological dysfunctions, as well as strategic infarct dementia. However, only a limited number of reports in the medical literature have discussed the correlation between the clinical findings and the specific functional changes observed on images. We investigated the neuropsychological correlation of the regional cerebral blood flow (rCBF) deficits in four patients with left anterior thalamic infarction within two days after their stroke. All of the patients showed anterograde amnesia on the verbal memory test. Some dysexecutive features were present such as decreased word fluency and an impaired performance on the Stroop test. A decreased rCBF was observed in the left supramarginal gyrus, the superior temporal gyrus, the middle and inferior frontal gyri, and the medial dorsal and anterior nuclei of the left thalamus. The changes of rCBF may have been due to remote suppression by the interruption of the thalamo-cortical circuit that connects the anterior thalamic nucleus and various cortical areas. These initial findings remained unchanged even on the follow-up studies.

Regional cerebral blood flow reductions, heart failure and Alzheimer's disease

Objectives: To discuss whether there are similarities between the functional brain abnormalities detectable in association with the diagnoses of heart failure (HF) and Alzheimer's disease (AD), focusing particularly on neuroimaging findings in vivo.Methods: Using an electronic database (Medline), we reviewed imaging studies that have evaluated resting cerebral blood flow (CBF), resting glucose metabolism or amyloid deposition in groups of subjects suffering AD or HF compared with healthy controls.Results: Single photon emission computed tomography (SPECT) investigations have reported global CBF reductions in HF groups compared with controls. In one recent SPECT study using modern voxel-based methods for image analysis, regional CBF deficits in the pre-cuneus and posterior cingulate gyrus were detected in a sample of HF sufferers relative to controls. The regional distribution of functional deficits in the latter study was similar to that found in many positron emission tomography (PET) investigations of glucose metabolism at early AD stages, as well as in recent PET investigations of amyloid deposition in AD.Discussion: Imaging studies have rarely investigated whether there are localized functional brain deficits in association with HF. Recent regional CBF SPECT data provide preliminary anatomic support to a view that AD-like brain changes may develop in HF patients, possibly as a consequence of chronic CBF reductions. Additional studies of larger HF samples are needed to confirm this possibility, preferably using PET measures that have afforded greater sensitivity and specificity to identify brain functional abnormalities associated with the diagnosis of AD, such as indices of glucose metabolism and amyloid deposition.

Blood Flow Imaging of the Brain: 50 Years Experience

Blood Flow Imaging of the Brain: 50 Years Experience

Regional cerebral blood flow deficits in mild Alzheimer's disease using high resolution single photon emission computerized tomography

In spite of its wide availability, single photon emission computerized tomography (SPECT) scanning is uncommonly used in the assessment of Alzheimer's disease (AD) and related dementias. In light of recent advances in scanning protocols and image analysis, SPECT needs to be re-examined as a tool in the diagnosis of dementia. A total of 18 subjects with early AD and 10 healthy elderly control subjects were examined with high resolution SPECT during the performance of a simple word discrimination task. SPECT images were coregistered with individual magnetic resonance imaging scans, allowing delineation of predetermined neuroanatomical Regions of Interest (ROI). There was a gradation of regional cerebral blood flow (rCBF) values in both groups, with the lowest values being in the hippocampus and the highest in the striatum, thalamus and cerebellum. Compared to healthy controls, AD subjects demonstrated lower relative rCBF in parietal and prefrontal cortices. Analysis of individual ROI demonstrated bilateral reduction of rCBF in prefrontal poles, posterior temporal and anterior parietal cortex, and unilateral reduction of rCBF in left dorsolateral prefrontal cortex, right posterior parietal cortex and the left cingulate body. There were no significant differences for hippocampal, occipital or basal ganglia rCBF. Discriminant function analysis indicated that rCBF in the prefrontal polar regions achieved the best classification of cases. SPECT has utility in the diagnostic assessment of AD if standardized and semiquantitative techniques are used.

A technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography study in adolescent patients with major depressive disorder.

We have not encountered any brain single-photon emission tomography (SPET) study performed in adolescent depressed patients in the literature. Therefore, we used technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) brain SPET in adolescent patients with major depressive disorder (MDD) to examine the possible changes in cerebral perfusion and the possible association between perfusion indices and clinical variables. Fourteen adolescent out-patients (nine females, five males; mean+/-SD age: 13.11+/-1.43 years; range: 11-15 years) fulfilling the DSM-IV criteria for MDD and 11 age-matched healthy control subjects (six females, five males; mean+/-SD age: 13.80+/-1.60 years; range: 12-15 years) were included in the study. 99Tc-HMPAO brain SPET was performed twice in the patient group and once in the control group. The first SPET investigation was performed under non-medicated conditions and the second was performed after depressive symptoms had subsided. A relative perfusion index (PI) was calculated as the ratio of regional cortical activity to the whole brain activity. We found significant differences between the PI values of the untreated depressed patients and those of the controls, indicating relatively reduced perfusion in the left anterofrontal and left temporal cortical areas. No significant differences in regional PI values were found between the remitted depressed patients and the controls. Our study suggests that adolescent patients with MDD may have regional cerebral blood flow deficits in frontal regions and a greater anterofrontal right-left perfusion asymmetry compared with normal subjects. The fact that these abnormalities in perfusion indices have a trend toward normal values with symptomatic improvement suggests that they may be state-dependent markers for adolescent MDD.