Gender differences in healthy aging and Alzheimer's Dementia: A 18F‐FDG‐PET study of brain and cognitive reserve

Cognitive reserve (CR) and brain reserve (BR) are protective factors against age‐associated cognitive decline and neurodegenerative disorders. Very limited evidence exists about gender effects on brain aging and on the effect of CR on brain modulation in healthy aging and Alzheimer's Dementia (AD). We investigated gender differences in brain metabolic activity and resting‐state network connectivity, as measured by ¹⁸F‐FDG‐PET, in healthy aging and AD, also considering the effects of education and occupation. The clinical and imaging data were retrieved from large datasets of healthy elderly subjects (HE) (225) and AD patients (282). In HE, males showed more extended age‐related reduction of brain metabolism than females in frontal medial cortex. We also found differences in brain modulation as metabolic increases induced by education and occupation, namely in posterior associative cortices in HE males and in the anterior limbic‐affective and executive networks in HE females. In AD patients, the correlations between education and occupation levels and brain hypometabolism showed gender differences, namely a posterior temporo‐parietal association in males and a frontal and limbic association in females, indicating the involvement of different networks. Finally, the metabolic connectivity in both HE and AD aligned with these results, suggesting greater efficiency in the posterior default mode network for males, and in the anterior frontal executive network for females. The basis of these brain gender differences in both aging and AD, obtained exploring cerebral metabolism, metabolic connectivity and the effects of education and occupation, is likely at the intersection between biological and sociodemographic factors. Hum Brain Mapp 38:4212–4227, 2017. © 2017 Wiley Periodicals, Inc.     

Gender differences in brain reserve

Background Neuropathological studies suggest that the association between neurodegenerative brain damage and clinical symptoms may be stronger in women than in men. Objective To test the hypothesis that cerebral metabolic deficits due to neurodegeneration are more pronounced in men than in women at the same level of clinical disease severity. Methods 93 patients with mild Alzheimer's disease (AD; 50 men, 43 women) underwent an extensive clinical and neuropsychological examination and ¹⁸F-FDG PET imaging at a university-based outpatient unit for cognitive disorders. An analysis of covariance (with age, total score of the CERAD neuropsychological battery, and years of school education as covariates) was conducted in each study group to identify gender differences in glucose metabolism. Results Controlling for age, education, and clinical severity, cortical regions were identified,where glucose metabolism was significantly reduced in men as compared with women. These regions were located in areas typically affected by AD pathology (right inferior frontal, superior temporal and insular cortex, and hippocampus). Conclusions These data suggest that the same clinical severity of dementia is associated with greater reductions in cerebral metabolism in men than in women suggesting a greater degree of brain reserve in men.     

PET imaging of ischemia-induced impairment of mitochondrial complex I function in monkey brain

To assess the capability of ¹⁸F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoroethoxy)-ethoxy]-pyridin-3-ylmethoxy}-2H-pyridazin-3-one (¹⁸F-BCPP-EF), a novel positron emission tomography (PET) probe for mitochondrial complex I (MC-I) activity, as a specific marker of ischemia-induced neuronal death without being disturbed by inflammation, translational research was conducted using an animal PET in ischemic brains of Cynomolgus monkeys (Macaca fascicularis). Focal ischemia was induced by the right middle cerebral artery occlusion for 3 hours, then PET scans were conducted at Day-7 with ¹⁵O-gases for regional cerebral blood flow (rCBF) and regional cerebral metabolism of oxygen (rCMRO₂), and ¹⁸F-BCPP-EF for MC-I with arterial blood sampling. On Day-8, the additional PET scans conducted with ¹¹C-flumazenil (¹¹C-FMZ) for central-type benzodiazepine receptors, ¹¹C-PBR28 for translocator protein, and ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) for regional cerebral metabolic rate of glucose (rCMRglc). The total distribution volume (V_T) values of ¹⁸F-BCPP-EF showed the significant reduction in MC-I activity in the damaged area at Day-7. When correlated with rCBF and rCMRO₂, the V_T values of ¹⁸F-BCPP-EF provided better correlation with rCMRO₂ than with rCBF. In the inflammatory regions (region of interest, ROI_PBR) of the ischemic hemisphere detected with ¹¹C-PBR28, higher ¹⁸F-FDG uptake and lower V_T of ¹⁸F-BCPP-EF, ¹¹C-FMZ, and rCMRO₂ than those in normal contralateral hemisphere were observed. These results strongly suggested that ¹⁸F-BCPP-EF could discriminate the neuronal damaged areas with neuroinflammation, where ¹⁸F-FDG could not owing to its high uptake into the activated microglia.     

Regional correlation between resting state FDG PET and pCASL perfusion MRI

To determine how arterial spin labeling (ASL) measured perfusion relates to baseline metabolism, we compared resting state cerebral perfusion using pseudo-continuous ASL and cerebral glucose metabolism using ¹⁸F-FDG PET in 20 normal volunteers. Greater regional metabolism relative to perfusion was observed in the putamen, orbitofrontal and temporal lobes, whereas perfusion was relatively higher in the hippocampus and insula. In a region of interest analysis limited to gray matter, the overall mean correlation between perfusion and metabolism across voxels was r=0.43 with considerable regional variability. Cross-voxel correlations between relative perfusion and metabolism in mean ASL and PET images of all 20 subjects were the highest in the striatum (caudate: r=0.78; putamen: r=0.81), and the lowest in medial temporal structures (amygdala: r=0.087; hippocampus: r=−0.26). Correlations between mean relative perfusion and metabolism across 20 subjects were the highest in the striatum (caudate: r=0.76; putamen: r=0.58), temporal lobe (r=0.59), and frontal lobe (r=0.52), but very poor in all other structures (r<0.3), particularly in caudal structures such as the hippocampus (r=−0.0026), amygdala (r=0.18), and insula (r=0.14). Although there was good overall correlation between perfusion and glucose metabolism, regional variability should be considered when using either ASL or ¹⁸F-FDG PET as surrogate markers for neural activity.     

Intranasal Insulin Ameliorates Cerebral Hypometabolism,Neuronal Loss,and Astrogliosis in Streptozotocin-Induced Alzheimer’s Rat Model

Intracerebroventricular injection of streptozotocin (ICV-STZ) in rodents leads to cognitive impairments and several pathological changes like Alzheimer’s disease (AD). However, there is hardly any research about the effect of ICV-STZ on regional cerebral glucose metabolism in rodents. Previous studies have demonstrated that intranasal insulin improves cognition in AD patients. However, the underlying mechanism remains elusive. Here, we treated the ICV-STZ rats with daily intranasal delivery of insulin (2 U/day) for 6 consecutive weeks, then monitored ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake using a high-resolution small-animal positron emission tomography (microPET) and studied the expression of neuronal nuclei (NeuN) and glial fibrillary acidic protein (GFAP) using immunohistochemical staining. We observed that ¹⁸F-FDG uptake decreased significantly at the prefrontal cortex, cingulate cortex, striatum, hippocampus, and entorhinal cortex in ICV-STZ rats as compared with the control rats. Intranasal insulin restores the cerebral glucose metabolism in prefrontal and cingulate cortex and attenuates astroglia activation and neuronal loss in the hippocampus of ICV-STZ rats. These findings provide the mechanistic basis for treating AD patients with intranasal insulin.     

Male gender is associated with greater cerebral hypometabolism in frontotemporal dementia: evidence for sex-related cognitive reserve

BACKGROUND: Neuropathological studies suggest that the association between neurodegenerative brain damage and clinical symptoms may be stronger in women than in men; therefore women are more likely to express neurodegeneration as clinical dementia. Furthermore, a recent 18F-FDG PET study explored gender differences in the regional cerebral metabolic rate of glucose (rCMRglc) in patients with Alzheimer's disease and found that, at the same level of severity of cognitive impairment, men showed a significantly greater hypometabolism than women. This suggests that men can compensate more pathology than women. OBJECTIVE: To test the hypothesis that cerebral metabolic deficits due to neurodegeneration are more pronounced in men than in women with frontotemporal dementia (FTD), controlling for cognitive impairment. METHODS: Twenty-nine patients with FTD (20 men, nine women) underwent an extensive clinical examination and 18F-FDG PET imaging at a university-based outpatient unit for cognitive disorders. An analysis of covariance (with age, total score of the CERAD neuropsychological battery, and years of school education as co-variates) was conducted to identify gender differences in glucose metabolism. RESULTS: Frontal cortical regions were identified where rCMRglc was significantly reduced in men as compared with women. These regions were located in the left middle, superior, and inferior frontal gyri and the right anterior cingulate, and superior frontal gyri (p < 0.001 uncorrected for multiple comparisons). CONCLUSION: The same level of severity of cognitive symptoms is associated with a more pronounced functional brain damage in male than in female patients with FTD, suggesting a greater degree of cognitive reserve in men.     

Normal and pathological aging – findings of positron-emission-tomography

Summary. Normal aging of the brain is predominantly characterized by metabolic changes in the prefrontal cortex. While in middle age there is a trend to hyperfrontality, PET demonstrates in old age a decline of regional cerebral glucose metabolism in frontal areas. In progeric diseases, clinically apparent as premature aging, the metabolic pattern is similar like in normal aging but qualitatively more severe. In patients with the diagnosis of probable Alzheimer's disease (AD) hypometabolism in early dementia is typically present in heteromodal association areas. Hypometabolism then spreads to other cortical and subcortical regions suggesting a characteristic pattern of degeneration that reflects selective vulnerability within limbic-cortical networks. Synaptic plasticity, clinically apparent as cognitive reserve capacity, can be assessed by PET under specific cognitive activation. In AD it is reduced in comparison to age-matched normals and may be influenced by drugs giving trophic support to neurochemical systems. Received December 17, 1997; accepted April 23, 1998     

Neuroprotective effect of the traditional Chinese herbal formula Tongxinluo： a PET imaging study in rats

Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography （PET） studies on the neuroprotective effect of Tongxinluo on cerebral ischemia/reperfusion in small animals. In the present study, Tongxinluo superfine powder suspension or its vehicle was administered intragastrically to rats for 5 successive days before middle cerebral artery occlusion, ^18Ffluorodeoxyglucose （FDG） small animal PET imaging showed that at 1 and 2 weeks after cerebral ischemia/reperfusion, glucose metabolism in the ischemic area was greater in rats that had received Tongxinluo than in those that had received the vehicle. Nissl staining showed that 2 weeks after cerebral ischemia/reperfusion, there was less neuronal loss in the prefrontal cortex in Tongxinluo-treated rats than in controls. In addition, Tongxinluo-treated animals showed better neurologic function and lower cerebral infarct volume than rats that received the vehicle. These findings suggest that Tongxinluo exhibits neuroprotective effects in cerebral ischemia/reperfusion injury and demonstrates that ^18F-FDG small animal PET imaging is a useful tool with which to study the molecular pharmacology of traditional Chinese medicine.     

Reduced uptake of 18F-FDG and 15O-H2O in Alzheimer's disease-related regions after glucose loading

Increased plasma glucose levels are known to reduce fluorine-18-labeled fluorodeoxyglucose (¹⁸F-FDG) uptake in Alzheimer''s disease (AD)-related regions, resulting in the appearance of an AD-like pattern. However, the relationships of its appearance with cerebral blood flow and insulin levels are uncertain. We performed ¹⁸F-FDG and oxygen-15-labeled water (¹⁵O-H₂O) positron emission tomography in the fasting and glucose-loading conditions on nine young healthy volunteers with no cognitive impairments. Measurement of plasma glucose and insulin levels confirmed that all subjects were free of insulin resistance, and that glucose loading significantly increased plasma glucose and insulin levels. Fluorine-18-labeled fluorodeoxyglucose and ¹⁵O-H₂O images were compared between the two conditions, focusing on AD-related regions: precuneus/posterior cingulate (PP), lateral parietal cortex (LPC), and frontal cortex (FC). Volume-of-interest analyses showed significantly lower uptake of both ¹⁸F-FDG and ¹⁵O-H₂O in PP, LPC, and FC after glucose loading (P<0.05). Whole-brain voxel-wise analyses also revealed the PP, LPC, and FC areas where uptake of both ¹⁸F-FDG and ¹⁵O-H₂O decreased (P<0.05, familywise error rate-corrected). We concluded that increased plasma glucose and insulin levels can cause the appearance of the AD-like pattern in both ¹⁸F-FDG and ¹⁵O-H₂O images, and this phenomenon can occur even in subjects without insulin resistance.     

Longitudinal Imaging of Regional Brain Volumes,SV2A,and Glucose Metabolism In Huntington's Disease

Background

Development of disease-modifying treatments for Huntington's disease (HD) could be aided by the use of imaging biomarkers of disease progression. Positron emission tomography (PET) with ¹¹C-UCB-J, a radioligand for the brain-wide presynaptic marker synaptic vesicle protein 2A (SV2A), detects more widespread brain changes in early HD than volumetric magnetic resonance imaging (MRI) and ¹⁸F-fludeoxyglucose (¹⁸F-FDG) PET, but longitudinal ¹¹C-UCB-J PET data have not been reported. The aim of this study was to compare the sensitivity of ¹¹C-UCB-J PET, ¹⁸F-FDG PET, and volumetric MRI for detection of longitudinal changes in early HD.

Methods

Seventeen HD mutation carriers (six premanifest and 11 early manifest) and 13 healthy controls underwent ¹¹C-UCB-J PET, ¹⁸F-FDG PET, and volumetric MRI at baseline (BL) and after 21.4 ± 2.7 months (Y2). Within-group and between-group longitudinal clinical and imaging changes were assessed.

Results

The HD group showed significant 2-year worsening of Unified Huntington's Disease Rating Scale motor scores. There was significant longitudinal volume loss within the HD group in caudate (−4.5% ± 3.8%), putamen (−3.6% ± 3.5%), pallidum (−3.0% ± 2.7%), and frontal cortex (−2.0% ± 2.1%) (all P < 0.001). Within the HD group there was longitudinal loss of putaminal SV2A binding (6.4% ± 8.8%, P = 0.01) and putaminal glucose metabolism (−2.8% ± 4.4%, P = 0.008), but these changes were not significant after correction for multiple comparisons. Premanifest subjects at BL only had significantly lower SV2A binding than controls in basal ganglia structures, but at Y2 additionally had significant SV2A loss in frontal and parietal cortex, indicating spread of SV2A loss from subcortical to cortical regions.

Conclusions

Volumetric MRI may be more sensitive than ¹¹C-UCB-J PET and ¹⁸F-FDG PET for detection of 2-year brain changes in early HD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.     

Evaluation of FDG-PET and ECD-SPECT in patients with subcortical band heterotopia

Objective: The purpose of this retrospective study was to clarify the cellular activities of ectopic neurons in subcortical bands and to evaluate the imaging features of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and ^99mTc ethyl cysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in a series of patients with subcortical band heterotopia (SBH). Materials and methods: The cases of 12 patients with SBH (3 men and 9 women; age range, 2–51 years) were evaluated on the basis of their MRI findings. Eight ¹⁸F-FDG PET and 12 ^99mTc-ECD SPECT images were obtained. The uptakes of these images were compared with electroencephalography (EEG) or MRI findings such as band thickness. In all patients, easy Z-score Imaging System (eZIS) software was used to statistically analyze the SPECT images. Results: Of the eight ¹⁸F-FDG PET images, five showed higher uptake in the thick subcortical bands than in the overlying cortex. Of the 12 ^99mTc-ECD SPECT examinations with eZIS images, nine indicated increased regional cerebral blood flow (rCBF) areas corresponding to the band locations. Of the eight ¹⁸F-FDG PET examination findings, six were congruent with the rCBF distributions on the eZIS images. Eight of the 12 patients showed correspondence to the increased rCBF on the eZIS images, the band locations on MRI, and abnormal discharge sites on EEG. Conclusions: Ectopic neurons in subcortical bands may have higher glucose metabolism and/or increased rCBF compared to the overlying cortex. ¹⁸F-FDG PET and ^99mTc-ECD SPECT using eZIS can be helpful to clearly detect the cellular activities of ectopic neurons in patients with SBH.     

Dopamine transporters, D2 receptors, and glucose metabolism in corticobasal degeneration.

Alterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. (123)I-FP-CIT/(123)I-beta-CIT SPECT and (123)I-IBZM SPECT as well as (18)F-FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. (18)F-FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD.     

Lateralisation of striatal function: evidence from 18F-dopa PET in Parkinson's disease

OBJECTIVES: The aetiology of the cognitive changes seen in Parkinson's disease (PD) is multifactorial but it is likely that a significant contribution arises from the disruption of dopaminergic pathways. This study aimed to investigate the contribution of the dopaminergic system to performance on two executive tasks using (18)F-6-fluorodopa positron emission tomography ((18)F-dopa PET) in PD subjects with early cognitive changes. METHODS: 16 non-demented, non-depressed PD subjects were evaluated with the Tower of London (TOL) spatial planning task, a verbal working memory task (VWMT) and (18)F-dopa PET, all known to be affected in early PD. Statistical parametric mapping (SPM) localised brain regions in which (18)F-dopa uptake covaried with performance scores. Frontal cortical resting glucose metabolism was assessed with (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET. RESULTS: SPM localised significant covariation between right caudate (18)F-dopa uptake (Ki) and TOL scores and between left anterior putamen Ki and VWMT performance. No significant covariation was found between task scores and (18)F-dopa Ki values in either limbic or cortical regions. Frontal cortical glucose metabolism was preserved in all cases. CONCLUSIONS: These findings support a causative role of striatal dopaminergic depletion in the early impairment of executive functions seen in PD. They suggest that spatial and verbal executive tasks require integrity of the right and left striatum, respectively, and imply that the pattern of cognitive changes manifest by a patient with PD may reflect differential dopamine loss in the two striatal complexes.     

Comparison of cerebral glucose metabolism between multiple system atrophy Parkinsonian type and Parkinson's disease

OBJECTIVE: To investigate the difference in the regional cerebral glucose metabolism between multiple system atrophy Parkinsonian type (MSA-P) and Parkinson's disease (PD). MATERIAL AND METHODS: Fifteen patients with MSA-P, 32 patients with PD and eight cases of healthy control underwent positron emission tomography (PET) with (18)F-fluorodeoxyglucose ((18)F-FDG) showing glucose metabolism. Glucose metabolism ratios of various cerebral regions were compared as an indicator of regional cerebral glucose metabolic patterns. RESULTS: The metabolism ratios of frontal lobe/occipital lobe, parietal lobe/occipital lobe, temporal lobe/occipital lobe and corpus striatum/occipital lobe in patients with MSA-P were lower than those in patients with PD and control, respectively (p<0.01). For patients with MSAP, the metabolism ratio in thalamus was higher than those in lenticular nucleus and anterior cortical brain, respectively (p<0.01) and the changes of metabolism ratio in cortex, corpus striatum and thalamus were symmetric. For patients with PD, the metabolism ratio in corpus striatum was higher than that in thalamus and two side of the basal ganglia show asymmetric change of metabolism (p<0.01). CONCLUSION: This study suggests that significant differences exist in the patterns of regional cerebral glucose metabolism between MSA-P and PD. (18)F-FDG PET might be a useful adjunctive method for differential diagnosis between MSA-P and PD.     

Cerebral metabolic correlates of the clinical dementia rating scale in mild cognitive impairment

Mild cognitive impairment (MCI) is often a prodromal state of Alzheimer's disease (AD). Imaging studies have shown that metabolic deficits in cerebral regions known to be affected early by AD pathology are predictive of progression to AD. In the present article, the authors examine associations between clinical impairment (Clinical Dementia Rating scale sum of boxes [CDR-SB]) and regional deficits in glucose utilization in a sample of 41 patients with MCI, who underwent cerebral 18F-FDG PET for the measurement of regional glucose metabolism. A linear regression analysis with CDR-SB score as the independent variable and glucose metabolism as the dependent variable, adjusted for age, gender, and years of school education, was conducted in voxel-by-voxel fashion in SPM2. The regression analysis revealed a significant negative association between CDR-SB score and glucose metabolism in the right posterior cingulate gyrus (P < .001, uncorrected for multiple comparisons), which was independent from demographical variables. The authors conclude that clinical severity of impairments is already correlated with deficits in glucose metabolism in the stage of MCI.     

局灶性难治性颞叶癫痫全脑葡萄糖代谢特点

目的 探讨局灶性难治性颞叶癫痫全脑葡萄糖代谢特点。方法 回顾性分析2017年1~12月行发作间期18FDG-PET/CT检查的23例局灶性难治性颞叶癫痫的影像学资料。将PET图像导入MIM neuro软件,软件自动分析癫痫病人葡萄糖代谢水平与正常人群葡萄糖代谢的差异,各脑区差异结果以Z-Score值显示,分析颞叶癫痫病人全脑葡萄糖代谢特点。结果 术后病理为脑皮质发育不良22例,节细胞胶质瘤1例;病灶位于左侧颞叶16例,右侧颞叶7例。除颞叶呈葡萄糖低代谢改变外,还存在同侧海马、海马旁回、岛叶、杏仁核、颞叶岛盖以及双侧小脑半球葡萄糖代谢不同程度减低;对侧颞叶、额叶、顶叶、顶上小叶以及角回葡萄糖代谢不同程度增高。结论 颞叶癫痫具有一定葡萄糖代谢特点,其特定的葡萄糖代谢特点有助于更加精准的癫痫术前定位及其病理特征的分析。     

Immobilization dystonia

OBJECTIVE: Some studies have examined gender differences in brain function based on cerebral blood flow and cerebral metabolism by using positron emission tomography (PET). However, the findings of these studies are controversial and most of them were analyzed by the regions of interest (ROIs) method. Here, we evaluated gender differences of cerebral glucose metabolism under the resting state in a voxel-based analysis. METHODS: We studied 44 healthy volunteers (22 females, 63.0+/-6.3 years, and 22 males, 63.1+/-8.4 years). Cerebral glucose metabolic images were obtained with (18)F-fluorodeoxyglucose (FDG) and PET. All individual data were transformed to standard brain space and the male and female groups were compared using statistical parametric mapping (SPM). RESULTS: The males had significantly higher glucose metabolism in the right insula, middle temporal gyrus, and medial frontal lobe than the females. Glucose metabolism in the hypothalamus was significantly higher in females than in males. There was a significant correlation between aging and glucose metabolism in the left thalamus in males and in the left caudate nucleus and hypothalamus in females. In males, but not females, there was a significant asymmetry between the bilateral hemispheres. CONCLUSION: We found that there were obvious gender differences in regional cerebral glucose metabolism and this is the first report of higher glucose metabolism in the hypothalamus in females than in males.     

Reversal of cerebral glucose hypometabolism on positron emission tomography with electroconvulsive therapy in an elderly patient with a psychotic episode

AB, a 74‐year‐old Caucasian woman, was admitted for acute onset of psychosis, anxiety, and cognitive impairment. Pharmacotherapy was unsuccessful and the patient was referred for electroconvulsive therapy (ECT). Pre‐ECT, ¹⁸F‐fluorodeoxyglucose‐positron emission tomography (PET)/computed tomography showed extensive frontal, parietal, and temporal cortical hypometabolism suggestive of a neurodegenerative disease. After eight ECT sessions, the psychotic and anxiety symptoms as well as the cognitive impairment resolved. The rapid improvement in symptoms was more suggestive of a psychotic episode rather than dementia. Two days after the ECT course, ¹⁸F‐fluorodeoxyglucose‐PET/computed tomography showed improvements in cerebral cortical hypometabolism, especially in the left parietal cortex, left temporal/occipital cortex. and bifrontal regions. At a follow‐up visit 2 months after the ECT course, the psychotic episode was still in remission, and ¹⁸F‐fluorodeoxyglucose‐PET/computed tomography continued to show improved cerebral cortical hypometabolism in these areas. This case illustrated the effect of ECT in reversing cerebral glucose hypometabolism on PET. The improvement in cerebral glucose hypometabolism may represent the neurophysiological mechanism of ECT in the treatment of a psychotic episode. Improved cerebral glucose hypometabolism was present 2 months post‐ECT, which suggests that ECT caused sustained functional neural changes.     

癫痫患儿脑FDG-PET显像与发作类型、脑电图异常及手术效果的相关性

目的 探讨小儿癫痫发作类型、脑电图异常、手术效果等与癫痫患儿脑FDG-PET显像的相关性.方法 方法回顾经临床、脑电图、影像学检查确诊的并行手术治疗的71例癫痫患儿脑18F-FDG-PET显像检测结果,以了解癫痫灶脑细胞葡萄糖代谢情况.根据脑FDG-PET显像结果,将71例患儿分为3个代谢减低组.33例患儿脑代谢减低位于单个脑叶,28例位于两个脑叶,10例多个脑叶均见代谢减低.收集71例患儿病程、性别、年龄、发作类型、脑电图资料、手术效果等临床资料,采用卡方检验,统计分析3个代谢减低组之间临床资料的总构成比差别.结果 癫痫发作类型、癫痫放电异常程度和术后效果在脑代谢减低3组间均有明显的区别,差异有统计学意义(P＜0.05).结论 脑FDG-PET显像与手术效果、发作类型和脑电图异常均明显相关.     

18F-FDG PET/CT脑显像评价认知障碍患者中的脑小血管病变对皮层功能的影响

目的 探讨18氟代脱氧葡萄糖（18F-fluorodeoxyglucose,18F-FDG）正电子发射断层成像/计算机断层扫
描（positron emission tomography/computed tomography,PET/CT）脑显像评价认知障碍患者中的脑小血
管病变对皮层功能的影响。
方法 本研究为回顾性研究,纳入2009年1月～2010年12月北京协和医院PET中心行18F-FDG PET/CT
脑显像且颅脑磁共振成像（magnetic resonance imaging,MRI）提示存在小血管病变的认知障碍患者21例,
其中临床诊断血管性痴呆（vascular dementia,VaD）10例,阿尔茨海默病（Alzheimer’s disease,AD）或混
合型痴呆（mixed dementia,MD）11例。首先目测两组患者的18F-FDG PET/CT脑显像皮层及皮层下核团代
谢减低特点,并结合颅脑MRI判断病变血管对脑代谢的影响。使用NeuroQ软件和Scenium软件对18F-FDG
PET/CT脑图像在像素基础上进行定量分析比较两组患者的皮层代谢情况。
结果 通过目测和NeuroQ软件分析发现VaD组患者18F-FDG PET/CT脑显像图像特点为无规律,不对
称皮层或皮层下核团代谢减低,其中额叶皮层代谢减低范围最广,程度最重。结合颅脑MRI改变,考
虑皮层和皮层下核团代谢减低主要为小血管病变引起。AD或MD组患者脑代谢均呈现双侧颞顶叶代谢
减低,其中8例出现皮层代谢减低不对称表现,6例出现基底节丘脑不对称代谢减低表现,与典型AD
的表现不符,结合颅脑MRI表现,考虑为病变血管所致,小血管病变可能导致相应皮层代谢减低。通
过定量分析发现两组患者的SUV比值在左右顶叶、内外颞叶和枕叶差异具有显著性。
结论 18F-FDG PET/CT脑显像作为功能影像可以推断小血管病变与皮层及皮层下核团代谢的关系。