多探针PET成像观察轻度认知障碍

Multi-tracer PET imaging observation on mild cognitive impairment

目的观察轻度认知障碍患者(MCI)β淀粉样蛋白(Aβ)斑块、tau蛋白沉积和FDG PET特征。方法自ADNI数据库下载半年内接受Aβ-PET、tau-PET和FDG-PET成像的40例MCI患者及30名健康人(NC组),基于视觉判断其有/无皮层Aβ滞留,并据此将MCI患者分为Aβ+MCI组和Aβ-MCI组。分别对Aβ+MCI组和Aβ-MCI组与NC组进行逐像素统计分析,提取Aβ+MCI组AD特征脑区的平均图像强度值,分析FDG与Aβ斑块和tau蛋白沉积的相关性。结果相比NC组,Aβ+MCI组Aβ斑块呈全脑弥漫升高,边缘系统和新皮层tau蛋白对称性沉积增加,双侧扣带回、顶叶及楔前叶FDG代谢降低;FDG摄取与Aβ斑块无明显相关(P均>0.05),在杏仁核(r=-0.56,P<0.01)、扣带回后部(r=-0.61,P<0.01)、海马(r=-0.45,P=0.04)、海马旁回(r=-0.51,P=0.02)、楔前叶(r=-0.49,P=0.02)和颞中回(r=-0.53,P=0.01)与tau蛋白沉积呈负相关,在顶叶亦无明显相关(r=0.01,P=0.97)。Aβ-MCI组Aβ斑块和tau蛋白沉积低于NC组。结论Aβ+MCI具有阿尔茨海默病(AD)的PET特征,可视为AD前驱阶段。

Objective To observe PET characteristics of amyloid-β(Aβ)plaque,tau proteinosis and FDG in patients with mild cognitive impairment(MCI).Methods Forty patients with MCI and 30 normal subjects(NC group)were recruited from ADNI database.All subjects underwent multi-tracer PET imaging,comprising Aβ-PET,tau-PET and FDG-PET.According to visually comprising evaluation of whether there was Aβplaque or not in cortex,MCI patients were divided into Aβ+MCI group and Aβ-MCI group.Then all the subjects were statistically analyzed pixel by pixel,and the average image intensity of AD characteristic brain areas in Aβ+MCI group was extracted.Correlations between FDG Aβplaques and tau proteinosis were analyzed,respectively.Results Compared with NC group,Aβplaques increased through whole brain in Aβ+MCI group,while symmetrical deposition of tau increased in bilateral limbic system and neocortex,and hypo-metabolism of FDG decreased in bilateral cingulate gyrus,parietal lobe and precuneus.No obvious correlation was found between FDG and Aβplaques(all P>0.05).Significant negative correlations were found between FDG and tau proteinosis in amygdala(r=-0.56,P<0.01),posterior cingulate gyrus(r=-0.61,P<0.01),hippocampus(r=-0.45,P=0.04),parahippocampal gyrus(r=-0.51,P=0.02),precuneus(r=-0.49,P=0.02)and middle temporal gyrus(r=-0.53,P=0.01),but not in parietal lobe(r=0.01,P=0.97).Aβplaques and tau proteinosis in Aβ-MCI group were lower than those in NC group.Conclusion Aβ+MCI patients had PET characteristics similar to Alzheimer’s disease(AD),and could be regarded as the precursor stage of AD.