正常脑老化进程中脑局部葡萄糖代谢减低的规律
Age-Related Regional Cerebral Glucose Metabolism Reduction in Healthy Normal Volunteers
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摘要: 目的:利用统计参数图(SPM)分析正常人脑PET图像,研究正常脑老化进程中脑局部葡萄糖代谢减低的规律。方法:将266例(21~87岁)健康体检者的PET脑图像,按年龄以10岁为一个年龄段,分成7个组。在Matlab平台上用SPM2软件对7个组中每相邻两组进行组间分析,并以20~29岁组作为基准,其他各年龄组分别与该基准组进行比较,设统计学检验显著性阈值P为0.001。结果:SPM分析显示:①随着年龄的增长,全脑代谢减低区范围逐渐扩大,且程度逐渐加重,于70~79岁时达到高峰,80岁以后代谢减低进程有所减慢;②随着年龄的增长,不同脑区出现代谢减低的时间段不同:40岁之前未见明显代谢减低区;40~49岁仅有左侧额叶出现很小范围的代谢减低,是最先出现代谢减低的脑区;50~59岁右侧额叶、右侧顶叶和前扣带回出现代谢减低;60~69岁双侧顶叶和尾状核出现代谢减低;③随着年龄的增长,不同脑区代谢减低的程度不同:按程度由高到低依次为双侧额叶、前扣带回、双侧顶叶、尾状核头、双侧颞叶及小脑;④各年龄段均未见双侧枕叶、后扣带回、壳核和丘脑出现代谢减低。结论:脑老化进程中,正常人脑葡萄糖代谢减低的程度和范围与年龄呈正相关;不同脑区出现代谢减低的时间段不同,左侧额叶是最早出现代谢减低的脑区;不同脑区代谢减低的程度不同,其中以双侧额叶及前扣带回代谢减低最为明显。Abstract: Objective:The main objective of this study was to evaluate the age-related changes of the regional cerebral glucose metabolism in normal healthy volunteers utilizing Statistical Parametric Mapping(SPM)software. Methods:1 8F-FDG PET images of the entire brain were obtained in 266 healthy normal volunteers(173 men,93 women),age range from 21 to 87 yr.They were divided into 7groups according to their age(every 10 year for a group).Each group was compared with the next 10year group and each group(age>30yr)was compared with the basal states(the group of 20~29 yr)using SPM 2(two sample t-test,P<0.001).The hypo-metabolic areas were shown and the voxel value of each active area can be calculated.Results:The cerebral glucose metabolism of the entire brain was decreased with aging and it decreased the most during the seventies.②The regional cerebral glucose metabolism of different anatomic regions decreased in different stages.There was no glucose metabolism decrease in any anatomic region before 40.At forties only the left frontal lobes showed a glucose metabolism reduction.At fifties regional cerebral glucose metabolism reduction were seen in right frontal lobe,right parietal lobe and anterior cingulate gyrus.At sixties regional cerebral glucose metabolism reduction were seen in bilateral parietal lobes and caudate nucleus.③The regional cerebral glucose metabolism of different anatomic regions decreased at different levels.The greatest reduction in regional cerebral glucose metabolism occurred within the bilateral frontal lobes,followed by anterior cingulate gyrus,parietal lobes,caudate nucleus,temple lobes and cerebellum.④Bilateral occipital lobe,posterior cingulate gyrus,dorsal caudate putamen and thalamus remained metabolically unchanged with advancing age.Conclusion:We observed an age-related reduction in regional cerebral glucose metabolism mainly in the bilateral frontal gyrus,bilateral cingulate gyrus,bilateral parietal lobes and bilateral caudate nucleus.The reduction of the regional cerebral glucose metabolism in these lobes began at in different stages and the first reduction occurred in the left frontal lobe.The metabolism of different anatomic regions decreased at different levels and the greatest reduction occurred within the bilateral frontal lobes and bilateral anterior cingulate gyrus.