正常人脑局部葡萄糖代谢随年龄变化的PET表现

The study of regional cerebral glucose metabolic change in human being normal aging process by using PET scanner

目的利用^18F-脱氧葡萄糖（FDG）PET／CT脑代谢显像和统计参数图（SPM）软件研究正常人脑局部葡萄糖代谢随年龄变化的趋势。方法收集本中心252名行^18F-FDGPET／CT全身健康体格检查者（21—88岁）的PET脑图像，按年龄分成6组（21—70岁以10岁为1个年龄段分5个组，71～88岁归为1个组）。采用SPM软件将I〉31岁的各年龄段PET脑图像数据均与21～30岁年龄段作比较，用MNIspaceutility（MSU）定位软件对差异有统计学意义的像素簇进行立体定位，并计算各葡萄糖代谢减低脑区的体素值。统计学差异以P〈0．0001为界值。结果SPM及MSU分析显示：以21～30岁年龄段作参照，60岁及其以前各年龄段脑葡萄糖代谢无明显减低；60岁以后（〉60岁）代谢减低进程显著加快，涉及双侧额叶（主要是前运动皮质和前额叶背外侧及额极）、颞叶（主要是颞极）、岛叶、前扣带回及小脑，其中额叶代谢减低最明显，其次是前扣带回、颞叶、岛叶、小脑，且均以右侧半球代谢减低为显著；而顶叶、海马旁回、基底节及丘脑随年龄增长代谢减低不明显。结论正常人脑老化表现出代谢功能非匀速性及非对称性地减低特征。60岁及以前脑代谢功能减退不明显，60岁以后（〉60岁）双侧额叶、颞叶、岛叶、前扣带回及小脑代谢功能迅速减退，且右侧半球减退比左侧半球明显。

Objective With the technique development, PET has been more and more applied in brain function research. The aim of this study was to investigate the tendency of regional cerebral glucose metabolism changes in human being normal aging process by using lSF-fluorodeoxyglucose （FDG） PET/CT and statistical parametric mapping （SPM） software. Methods ^18F-FDG PET/CT brain imaging data acquired from 252 healthy normal subjects （age ranging：21 to 88 years old） were divided into 6 groups according to their age： 21 -30, 31 -40, 41 -50, 51 -60, 61 -70, 71 -88. All 5 groups with age≥31 years old were compared to the control group of 21 -30 years old, and pixel-by-pixel t-statistic analysis was applied using the SPM2. The hypo-metabolic areas were identified by MNI space utility （MSU） software and the voxel value of each brain areas were calculated （ P 〈 0.0001 ）. Results Compared with the group of 21 - 30 years old, the groups of ≤60 years old showed no significant metabolic decreases, while the groups of 〉 60 years old showed significant metabolic decreases with aging mainly involved bilateral frontal lobe （pre-motor cortex, dorso-lateral prefrontal cortex, frontal pole）, temporal lobe （temporal pole）, insula, anterior cingulate cortex and cerebellum. The most significant metabolic decrease area with aging was the frontal lobe , followed by the anterior cingulate cortex, temporal lobe, insula and cerebellum at predominance right hemisphere （P 〈 0.0001 ）. Parietal lobe, parahippocampal gyrus, basal ganglia and thalamus remain metabolically unchanged with advancing aging. Conclusions Cerebral metabolic function decrease with normal aging shows an inconstant and unsymmetrical process. The regional cerebral metabolic decrease much more significantly in older than 60 years old healthy volunteers, mainly involving bilateral frontal lobe, temporal lobe, insula, anterior cingulate cortex and cerebellum at right predominance hemisphere.