阿尔茨海默病~(18)F-FDG PET显像诊断的研究

目的 探讨阿尔茨海默病（AD）脑葡萄糖代谢及其18F-脱氧葡萄糖正电子发射计算机断层扫描（18F-FDG PET）显像的影像学特征和PET诊断标准。方法 静脉注射18F-FDG后行脑断层显像,检查13例 AD、13例非AD痴呆及13例正常人。获得纹状体、丘脑、黑质、顶叶、颞叶、额叶、枕叶、海马单位面积放射性计数与小脑计数的比值（Rcl/cb）,进行半定量分析,并与MR进行对照。结果AD患者PET异常率为100％,MR异常者占10/13。PET显像特征:①对称性双侧颞顶叶及海马伴额叶或枕叶代谢减低占9例（9/13）;②双侧颞叶对称性代谢减低伴海马或额叶代谢下降占3例（3/13）;③双顶叶对称性代谢降低1例（1/13）。12例（12/13）非AD痴呆表现为不对称、多发性代谢降低,降低区位于黑质、纹状体、丘脑及脑皮质区,MR异常率为11/13。结论 在除外脑内结构特异性损害基础上,PET发现对称性双颞顶叶、海马或颞叶、顶叶,伴或不伴枕叶、额叶代谢下降,可诊断AD。PET对AD早期诊断及鉴别诊断具有临床意义。

The study of the diagnosis of Alzheimer's disease using I8F-FDG PET.

Objective To study glucose metabolism of the brain in Azheimer's disease by positron emission tomography (PET) , and to investigate the imaging characteristics and diagnosis criteria of 18F-FDG PET in Chinese Alzheimer's disease(AD). Methods Fifty minutes after intravenous administration of F-FDG, brain scan was performed using Siemens ECAT EXACT HR scanner in 13 patients with AD, 13 patients with non-AD dementia including Pakinson disease with dementia(PDD), vascular dementia (VD) and AD-VD, and 13 age-matched healthy subjects. The transaxial, coronal and sagittal images were reconstructed by computer. Semiquantitative analysis was applied to assess the metabolic function of the brain by the ratio of mean radioactivity of cerebral lode to cerebellum (Rcl/cb). PET scan was compared with magnetic resonance imaging (MRI). Results 100% of AD patients showed abnormal PET imagines, whereas 76.92% of AD patients' showed abnormal MRI. The characteristics of PET imagines of AD patients had three patterns: (1) bilateral parietal, temporal, hippocampus and forntal or occipital lobe symmetrical hypometabolism in 69.23% AD cases; (2)bilateral temporal and hippocampus or frontal lobe symmetrical hypometabolism in 23.08% AD cases; (3)bilateral parietal symmetrical hypometabolism in 7.69% AD cases. The PET imagines of non-AD dementia showed that asymmetrical and multiple foci with decreased radioactivity and hypometabolism in 92.31% cases. The areas of hypometabolism were in nigro-striatum system, thalamus and cerebral. Conclusions Excluding cerebral structural lesions in brain with MRI, bilateral or symmetrical cerebral hypometabolism found in FDG PET can be considered as the special characteristics and diagnosis criteria of Alzheimer's disease. It is very important for the early diagnosis of AD and be differentiated from non-AD dementia .