18F-FDG和11C-PIB PET联合脑显像对阿尔茨海默病及额颞痴呆的鉴别诊断价值初探

摘要

目的 初步探讨11C-PIB和18F-FDG联合脑显像在阿尔茨海默病(AD)及额颞痴呆(FTD)鉴别诊断中的应用价值.方法 10例难以鉴别为AD或FTD的患者,行11C-PIB及18F-FDG PET联合脑显像.18例年龄匹配的健康老年人为对照组,行18F-FDG PET脑显像.18F-FDG结果应用统计参数图(SPM)进行基于体素水平分析,行2个样本t检验,P < 0.001认为有统计学意义.选取11C-PIB廓清及滞留情况对比明显的55~60 min图像进行视觉分析,PIB阳性定义为双侧额叶、顶叶、枕叶、颞叶及皮质下结构PIB放射性滞留较白质为著,小脑PIB廓清.PIB阴性定义为大脑皮层及皮质下结构、小脑无明显PIB滞留,仅在脑白质走行区少量放射性滞留.结果 18F-FDG与11C-PIB PET脑显像示典型AD图像5例,双侧颞-顶联合皮质区、楔前叶及后扣带回大脑葡萄糖代谢减低,PIB阳性.典型FTD图像2例,双侧额叶、前扣带回及双侧皮质下结构大脑葡萄糖代谢减低,PIB阴性.3例患者经18F-FDG脑显像仍难以鉴别,但11C-PIB脑显像提示AD 2例,FTD 1例,并且经5~6个月随访证实.结论 18F-FDG和11C-PIB联合脑显像能为AD及FTD鉴别诊断提供双重的影像学依据,尤其是在大脑葡萄糖代谢减低脑区相互重叠时,11C-PIB显像有助于进一步鉴别.%Objective To investigate the value of N-[11C] methyl-2 - methylamino-phenyl-6 - hydroxy - ben-zo-thiazole (11-PIB) and 18F-deoxyglucose (FDG) positron emission tomography (PET) in the differential diagnosis of Alzheimer's disease (AD) and frontotemporal dementia (FTD). Methods Ten patients who were difficult to diagnose for AD and FTD underwent 11C-PIB and 18F-FDG PET combined brain imaging. Eighteen age-matched healthy elderly controls underwent 18F-FDG PET. SPM8 software was used for FDG scan image data analysis. The 2-sample t-test was used in the study and P < 0.001 was considered statistically significant. The 55~60 min PIB scans were classified as positive or negative by visual analysis. PIB scans were rated as "PIB-positive" if tracer binding was deemed greater in cortical gray matter than in white matter, and as "PIB-negative" if only nonspecific white matter binding was observed. Results After undergoing amyloid and FDG PET scans, 5 typical AD images were distinguished. FDG imaging pattern presented as focal cortical hypome-tabolism in bilateral parietotemporal association cortexes and the posterior cingulated gyms, the precuneus. PIB was positive. There were two typical FTD images, showing the significant regional reductions in rCMRglc in bilateral frontal, the cingualte gyri, insulae and the subcortical structures. PIB was negative. Three patients, who underwent 18F-FDG brain imaging, were still difficult to identify. 11C-PIB brain imaging prompted 2 AD patients and 1 FTD patient, which were confirmed after 5 to 6-month follow-up. Conclusion PIB and FDG PET could provide dual functional information in the differential diagnosis of AD and FTD, especially the lower specificity in rCMRglc in some cases, PIB imaging was helpful.