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Regional cerebral blood flow was studied in 7 patients with clinically suspected Alzheimer's disease and 10 normal controls by single photon computed emission tomography (SPECT) using HM-PAO. All patients with Alzheimer's disease and no controls had parietal lobe hypoperfusion which was usually bilateral. In patients with more severe dementia hypoperfusion extended into the frontal lobes. Parietal lobe hypoperfusion corresponds to parietal lobe degeneration which is the one of the first neocortical regions to show the typical degenerative changes of Alzheimer's disease. SPECT with HM-PAO is a non-invasive investigation available in most nuclear medicine departments and complements existing tests in the routine evaluation of patients presenting with dementia.
BACKGROUND: Machado-Joseph disease (MJD) is one of the most frequently encountered spinocerebellar ataxias. However, few reports on brain single-photon emission computed tomographic (SPECT) imaging (BSI) with hexylmethylpropylene amineoxine labled with technetium Tc 99m and magnetic resonance imaging (MRI) have been performed for the evaluation of patients with MJD. OBJECTIVES: To investigate possible abnormalities with BSI and MRI in patients with MJD and to correlate these findings with the duration of symptoms; cerebellar, extrapyramidal, and pyramidal syndromes; and the molecular characteristics of the MJD mutation. PATIENTS AND METHODS: Twelve patients (8 males and 4 females [mean age, 39 years]) with genetically proven MJD were studied. The patients underwent BSI and MRI on the same day. Brain SPECT imaging was performed after an intravenous injection of 99mTc-hexylmethylpropylene amineoxine. The transaxial, coronal, and sagittal BSIs obtained were submitted to visual and semiquantitative analyses. Magnetic resonance imaging was obtained in a 2-T system with coronal, sagittal, transaxial, and 3-dimensional (volumetric) acquisitions. The volumes of the cerebellar hemispheres and vermis were calculated. Control groups for BSI (22 female and 20 male subjects [mean age, 33 years]) and MRI (13 female and 4 male subjects [mean age, 32.2 years]) were included for comparison. RESULTS: Correlation was observed between the perfusion abnormalities identified by visual analysis in the BSI with the structural abnormalities observed on MRI in the parietal lobes and vermis. Brain SPECT imaging identified (by visual analysis) more perfusion abnormalities in the inferior portion of the frontal lobes, mesial and lateral portions of the temporal lobes, basal ganglia, and cerebellar hemispheres. Magnetic resonance imaging identified more abnormalities in the pons and superior portions of the frontal lobes. Olivary atrophy was identified by MRI. Semiquantitative analysis showed a statistically significant difference of perfusion in the inferior and superior portions of the frontal lobes, lateral portion of the temporal lobes, parietal lobes, left basal ganglia, cerebellar hemispheres, and vermis when compared with the control group. A significant difference was noted between the vermis and cerebellar volumes on MRI when compared with the control group. A significant relationship was observed between the perfusion of the left parietal lobe (P =.05) and extrapyramidal syndrome. There was a tendency toward an inverse relationship between the duration of symptoms and the perfusion of the cerebellar hemispheres (rho = -0.37; P =.24) and volume of the vermis (rho = -0.30; P =.34); between the length of the expanded (CAG)n repeat and the perfusion of the left parietal lobe (rho = -0.32; P =.36), vermis (rho = -0.28; P =.43), and pons (rho = -0.28; P =.42). A direct association was observed between the length of the expanded (CAG)n repeat and the perfusion of the lateral portion of the right temporal lobe (rho = 0.67; P =.03). CONCLUSIONS: Brain SPECT imaging and MRI were capable of identifying subclinical abnormalities in individuals with MJD. These findings may be helpful for a better understanding of the pathophysiology of this disease.
Previous studies have led to the proposal that patients with Alzheimer's disease (AD) may have disturbed functional connectivity between different brain regions. Furthermore, recent resting-state functional magnetic resonance imaging (fMRI) studies have also shown that low-frequency (<0.08 Hz) fluctuations (LFF) of the blood oxygenation level-dependent signals were abnormal in several brain areas of AD patients. However, few studies have investigated disturbed LFF connectivity in AD patients. By using resting-state fMRI, this study sought to investigate the abnormal functional connectivities throughout the entire brain of early AD patients, and analyze the global distribution of these abnormalities. For this purpose, the authors divided the whole brain into 116 regions and identified abnormal connectivities by comparing the correlation coefficients of each pair. Compared with healthy controls, AD patients had decreased positive correlations between the prefrontal and parietal lobes, but increased positive correlations within the prefrontal lobe, parietal lobe, and occipital lobe. The AD patients also had decreased negative correlations (closer to zero) between two intrinsically anti-correlated networks that had previously been found in the resting brain. By using resting-state fMRI, our results supported previous studies that have reported an anterior-posterior disconnection phenomenon and increased within-lobe functional connectivity in AD patients. In addition, the results also suggest that AD may disturb the correlation/anti-correlation effect in the two intrinsically anti-correlated networks.
OBJECTIVE: To study the feature of regional cerebral metabolism rate of glucose (rCMRglc) of Alzheimer's disease (AD) and mild cognitive impairment (MCI) by positron emission tomography (PET) and the relationship between MCI and AD. METHODS: 13 AD patients, 10 MCI patients and 10 health volunteers as a control group (HC) were underwent 18F-fluoro deoxyglucose (18F-FDG)-PET scanning. RESULTS: (1) There was lightly decreasing of radioactivity of temporal lobe and parietal lobe in HC group, a little severer decrease in MCI group, markedly decrease of radioactivity of temporal lobe, parietal lobe and frontal lobe in AD group examined by naked-eye. (2) The rCMRglc of many parts of brain such as frontal lobe, including superior, middle and inferior frontal gyrus, orbital gyrus and rectus gyrus, temporal lobe, including superior, middle and inferior temporal gyrus, parietal lobe, including superior parietal lobe, supramarginal gyrus and angular gyrus, limbic system, including anterior cingulate gyrus, insular lobe, basal ganglions, including thalamus, caudate nucleus and amygdaloid nucleus decreased significantly in AD group, compared to MCI and HC groups (p < 0.05 to p < 0.001). (3) The rCMRglc of many parts of brain such as frontal lobe, temporal lobe, parietal lobe, limbic system, and basal ganglions in MCI group was lower than that in HC group, but not significantly (p > 0.05). Only that of the left caudate nucleus in MCI decreased significantly compared to that in HC group (p < 0.05). CONCLUSION: Decreasing of rCMRglc of parietal lobe is sensitive in evaluating cognitive function, next one is temporal lobe, and then frontal lobe. The rCMRglc of frontal lobe, temporal lobe, parietal lobe, limbic system, and basal ganglions decreasing markedly indicates that global function decayed in AD patients. While the rCMRglc of those parts in MCI patients' brain decreases mildly. This indicates that MCI is the middle state of AD and HC. Decreasing of rCMRglc of the left caudate nucleus has a certain role in diagnosis of MCI.
The incidence of cerebral amyloid angiopathy in a general population was evaluated in brains of 400 consecutive autopsies of residents of Hisayama, Japan (November 1971-October 1983). Six samples taken from frontal lobe, parietal lobe, temporal lobe, occipital lobe, hippocampus, and basal ganglia of the same side of each brain were stained with both hematoxylin and eosin and Congo red. The specimens were surveyed microscopically with polarized light for deposition of amyloid in the vascular wall. In 26 cases with brain hemorrhage, the region surrounding the hemorrhagic sites was further examined to study the probable causal relation between cerebral amyloid angiopathy and brain hemorrhage. Cerebral amyloid angiopathy was found in 40 of 218 men (18.3%) and 51 of 182 women (28.0%). The incidence increased with age in both sexes. The frontal lobe was most frequently affected (66 cases), followed by parietal lobe (65), occipital lobe (49), temporal lobe (44), and hippocampus (32); the putamen was never affected. The incidence of cerebral amyloid angiopathy did not correlate with blood pressure or with the severity of cerebral atherosclerosis. Among the 26 cases in which there was brain hemorrhage, only one cerebellar hemorrhage, in an 85-year-old man, was attributed to cerebral amyloid angiopathy. This case showed four microaneurysms in vessels, with cerebral amyloid angiopathy surrounding the hemorrhagic site. Thirty similar lesions were observed in eight cases without brain hemorrhage. Cerebral amyloid angiopathy may play an etiologic role in the development of brain hemorrhage through formation of angionecrosis and microaneurysm.
The chronological and spatial rules of changes during focal cerebral ischemia and reperfusion in different brain regions with magnetic resonance diffusion-weighted imaging (DWI) in a model of occlusion of middle cerebral artery (MCAO) and the development of cytotoxic edema in acute phase were explored. Fifteen healthy S-D rats with MCA occluded by thread-emboli were randomly divided into three groups. 15 min after the operation, the serial imaging was scanned on DWI for the three groups. The relative mean signal intensity (RMSI) of the frontal lobe, parietal lobe, lateral cauda-putamen, medial cauda-putamen and the volume of regions of hyperintense signal on DWI were calculated. After the last DWI scanning, T2 WI was performed for the three groups. After 15 min ischemia, the rats was presented hyperintense signals on DWI. The regions of hyperintense signal were enlarged with prolonging ischemia time. The regions of hyperintense signal were back to normal after 60 min reperfusion with a small part remaining to show hyperintense signal. The RMSIs of parietal lobe and lateral cauda-putamen were higher than that of the frontal lobe and medial cauda-putamen both in ischemia phase and recanalization phase. The three groups were normal on T2 WI imaging. DWI had good sensitivity to acute cerebral ischemia, which was used to study the chronological and spatial rules of development of early cell edema in ischemia regions.
Normative data on the in vivo size of the human brain and its major anatomically defined subdivisions are not readily available. In this study, high-resolution magnetic resonance imaging was used to measure regional brain volumes in 46 normal, right-handed adults (23 men, 23 women) between the ages of 22-49 years. Parcellation of the brain was based on neuroanatomical landmarks. The following brain regions were measured: the cerebral hemispheres, frontal lobe, temporal lobe, parietal lobe, occipital lobe, cingulate gyrus, insula, cerebellum, corpus callosum, and lateral ventricles. Males tend to be significantly larger than females, for the whole brain and for nearly all of its major subdivisions, including the corpus callosum. However, the proportional sizes of regions relative to total volume of the hemisphere are remarkably similar in males and females. Variation in size of region is always greater than variation in proportional representation. Asymmetries in brain regions are not profound, with the exception of the cingulate gyrus, which is larger in the left hemisphere. Brain regions are highly correlated in size, with the exception of the lateral ventricles. After controlling for hemisphere size, the volumes of the frontal and parietal lobes are significantly negatively correlated. The occipital lobe tends to be less sexually dimorphic than other major lobes, and less correlated with other brain regions for volume. These results have implications for understanding whether or not certain sectors of the brain have shown relative expansion over the course of hominid and hominoid evolution.
Glossolalia (or "speaking in tongues") is an unusual mental state that has great personal and religious meaning. Glossolalia is experienced as a normal and expected behavior in religious prayer groups in which the individual appears to be speaking in an incomprehensible language. This is the first functional neuroimaging study to demonstrate changes in cerebral activity during glossolalia. The frontal lobes, parietal lobes, and left caudate were most affected.
BACKGROUND: The pathogenesis of gait apraxia (GA) is unknown. Even though imaging studies provide excellent assessment of brain morphology, there is still a lack of congruous results. Single photon emission computed tomography (SPECT) using Tc-99m hexamethylpropyleneamine oxime (HMPAO) may show alterations in regional cerebral blood flow (rCBF) and provide indirect information about brain metabolism. METHODS: We conducted a SPECT study of GA patients and evaluated the related cortical function. rCBF was assessed in 16 GA patients (15 male, one female; age range 65-79 years, mean 70.5 years) by SPECT using HMPAO. Mean HMPAO cortical or basal ganglia/cerebellum activity ratios were calculated. The regions of interest included the frontal lobe, parietal lobe and basal ganglia. A battery of GA tests and magnetic resonance imaging (MRI) of the brain were also performed in these 16 patients. RESULTS: Nine of the patients had equilibrium disorder, and all 16 patients had locomotion disorder. The MRI findings were lacunar infarct (16/16 in basal ganglia, or 6/16 in thalamus), leukoaraiosis (4/16), enlarged ventricle (3/16), frontal lesion (3/16) and parietal lesion (1/16). Lower rCBF was noted in the frontal lobe (3/16), occipital lobe (1/16, thalamus (7/16) and basal ganglia (9/16). Though SPECT showed decreased rCBF in nine patients (9/16), mean cortical and basal ganglia regional uptake ratios in the patient group were not significantly different from values in the control group (cortical p = 0.0613; basal ganglia p = 0.0576, by Student's t-test). CONCLUSIONS: Though only a small number of patients were studied, it was clear that brain SPECT and MRI did not show any significant abnormalities in the frontal or parietal lobes of patients with GA. Thus, the pathogenesis of GA and its related anatomic lesion should be further investigated.
PURPOSE: To determine whether brain cortices have different signal intensities on turbo fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) images. MATERIALS AND METHODS: Coronal 5-mm-thick turbo FLAIR MR images in 56 neurologically normal patients (27 male and 29 female patients; age range, 12-73 years; mean age, 47 years) were evaluated retrospectively. Cortical signal intensities in the amygdala, hippocampus, cingulate gyrus, subcallosal area, insula, temporal lobe, parietal lobe, and occipital lobe were graded relative to cortical signal intensity in the frontal lobe. Contrast-to-noise ratios were compared for each cortical area. RESULTS: Increased signal intensity was frequently seen in the amygdala, hippocampus, cingulate gyrus, and subcallosal area, regardless of patient age. Signal intensities of temporal, parietal, and occipital cortices were similar to that of frontal cortex, and signal intensity of the insula was slightly higher than that of frontal cortex. There were no significant differences with respect to sex and laterality, whereas significant differences were found among cortical regions (P <.01). The contrast-to-noise ratios of the amygdala, hippocampus, cingulate gyrus, and subcallosal area were significantly greater than those of all other gray matter structures (P <.05). CONCLUSION: On turbo FLAIR images, high signal intensities of cortices of the limbic lobe are frequently seen in neurologically normal brain. These findings should not be considered abnormal.
OBJECTIVE: To study the biologic process of energy metabolism in brain during acupuncture using positron emission tomography (PET) with 18F-2-desoxyglucose (18FDG) for further elucidation of the relationship between acupunctural signal and nerve system. METHODS: Electroacupuncture (EA) was applied on right lateral of a healthy volunteer and paralytic limbs of 4 patients with cerebral infarction at acupoints L14, LI11, ST36 and SP6 using Hans acupoint-nerve stimulator. PET imaging was conducted on the healthy subject or patients with the same posture before and during EA with GE Advance II PET system. RESULTS: PET showed that in the healthy subject, before EA, the glucose metabolism (GM) in bilateral cerebral cortex, bilateral thalamus, basal nuclei and cerebellum was almost symmetrical, but during EA, the GM in contralateral thalamus, contralateral frontal lobe and parietal lobe (motor and sensory area) increased obviously. While in the patients before EA, the GM in the infarcted area was significantly lower than that in the non-infarcted area, as compared with that observed with CT and MRI, it showed a similar figure but with bigger abnormal area. During EA, GM in the infarcted area increased with apparent reduction of size. Increased GM of focal area, widened cerebral cortex and decreased edematous area were shown in patients with larger infarction area. Quantitative analysis revealed evident change in local/total ratio of glucose and increase of GM change rate. CONCLUSION: (1) EA on limb acupoints of healthy subject could induce obvious increase of regional GM in brain and contralateral thalamus, contralateral frontal lobe and parietal lobe (motor and sensory area). (2) EA on acupoints of paralytic limbs could cause increase of GM in contralateral thalamus, contralateral frontal lobe and parietal lobe. Besides, GM also increased in the area with lowered GM before EA, accompanied with shrinkage or disappearance of lesion. (3) Acupuncture could evoke the function of brain cells and raise the GM in them.
The cerebral blood flow and cerebrovascular reactivity to acetazolamide were investigated in Alzheimer's disease using stable xenon computed tomography (CT). Ten patients with Alzheimer's disease and 10 healthy controls were studied. The regional cerebral blood flow was measured using the xenon delivery and analysis system (AZ-7000 model, Anzai Sogyo, Tokyo, Japan) and CT (PreSage, Yokogawa Medical Systems, Tokyo, Japan). The subjects inhaled room air followed by a mixture of 30% xenon and 50% oxygen for 3 min. Serial scanning was performed once before xenon inhalation, three times in the wash-in process and five times in the washout process of 5 min. The xenon concentration in the end-tidal expired gas was recorded continuously by the thermoconductivity method. The regional cerebral blood flow was measured before and 20 min after i.v. injection of 17 mg/kg acetazolamide. The blood flows in the frontal lobe, parietal lobe and temporal lobe were reduced but the blood flows in the caudate nucleus, putamen and thalamus were normal in the Alzheimer's disease group. The cerebrovascular reactivity to acetazolamide was reduced in the frontal, parietal and temporal cortex but was normal in the other areas. There is a regional difference in the cerebral blood flow and the cerebrovascular reactivity to acetazolamide in Alzheimer's disease Copyright 1999 Harcourt Publishers Ltd.
Positron emission tomography (PET) with [18F]fluoro-D-deoxyglucose (FDG) has been used to detect seizure foci and evaluate surgical resection with localization related epilepsies. However, few investigations have focused on generalized epilepsy in children. To reveal the pathophysiology of generalized epilepsy, we studied 11 patients with generalized epilepsy except West syndrome, and 11 patients with localization related epilepsy without organic disease. The FDG PET was performed by simultaneous emission and transmission scanning. We placed regions of interest (ROI) on bilateral frontal lobe, parietal lobe, occipital lobe, temporal lobe, basal ganglia, thalamus and cerebellum. Standardized uptake value (SUV) was measured and normalized to SUV of ipsilateral cerebellum. Then, we compared the data of generalized epilepsy to those of localization related epilepsy. FDG PET revealed significant interictal glucose hypometabolism in bilateral basal ganglia in generalized epilepsy compared to that in localization related epilepsy (right side: p = 0.0095, left side: p = 0.0256, Mann-Whitney test). No other region showed any significant difference (p > 0.05) between the two groups. These findings indicate that the basal ganglia is involved in the outbreak of generalized seizures or is affected secondarily by the epileptogenicity itself.