Herholz Karl
Neurologische Universitätsklinik, Max-Planck-Institut für neurologische Forschung, Köln, Germany.
Ann Nucl Med. 2003 Apr;17(2):79-89. doi: 10.1007/BF02988444.
Measurement of local cerebral glucose metabolism (lCMRGlc) by positron emission tomography (PET) and 18F-2-fluoro-2-deoxy-D-glucose (FDG) has become a standard technique during the past 20 years and is now available at many university hospitals in all highly developed countries. Many studies have documented a close relation between lCMRGlc and localized cognitive functions, such as language and visuoconstructive abilities. Alzheimer's disease (AD) is characterized by regional impairment of cerebral glucose metabolism in neocortical association areas (posterior cingulate, temporoparietal and frontal multimodal association cortex), whereas primary visual and sensorimotor cortex, basal ganglia, and cerebellum are relatively well preserved. In a multicenter study comprising 10 PET centers (Network for Efficiency and Standardisation of Dementia Diagnosis, NEST-DD) that employed an automated voxel-based analysis of FDG PET images, the distinction between controls and AD patients was 93% sensitive and 93% specific, and even in very mild dementia (at MMSE 24 or higher) sensitivity was still 84% at 93% specificity. Significantly abnormal metabolism in mild cognitive deficit (MCI) indicates a high risk to develop dementia within the next two years. Reduced neocortical glucose metabolism can probably be detected with FDG PET in AD on average one year before onset of subjective cognitive impairment. In addition to glucose metabolism, specific tracers for dopamine synthesis (18F-F-DOPA) and for (11C-MP4A) are of interest for differentiation among dementia subtypes. Cortical acetylcholine esterase activity (AChE) activity is significantly lower in patients with AD or with dementia with Lewy bodies (DLB) than in age-matched normal controls. In LBD there is also impairment of dopamine synthesis, similar to Parkinson disease.
在过去20年中，通过正电子发射断层扫描（PET）和18F - 2 - 氟 - 2 - 脱氧 - D - 葡萄糖（FDG）测量局部脑葡萄糖代谢（lCMRGlc）已成为一项标准技术，目前在所有高度发达国家的许多大学医院都可进行。许多研究记录了lCMRGlc与局部认知功能之间的密切关系，如语言和视觉构建能力。阿尔茨海默病（AD）的特征是新皮质联合区域（后扣带回、颞顶叶和额叶多模态联合皮质）的脑葡萄糖代谢出现区域性损害，而初级视觉和感觉运动皮质、基底神经节和小脑相对保存完好。在一项由10个PET中心组成的多中心研究（痴呆诊断效率和标准化网络，NEST-DD）中，该研究采用基于体素的FDG PET图像自动分析，对照组和AD患者之间的区分敏感度为93%，特异度为93%，即使在非常轻度的痴呆（简易精神状态检查表[MMSE]评分为24分或更高）中，敏感度在特异度为93%时仍为84%。轻度认知障碍（MCI）中显著异常的代谢表明在未来两年内发展为痴呆的风险很高。平均而言，在主观认知障碍发作前一年，FDG PET可能就能检测到AD患者新皮质葡萄糖代谢降低。除了葡萄糖代谢外，用于多巴胺合成的特定示踪剂（18F - F - DOPA）和用于（未明确的11C - MP）的示踪剂对于区分痴呆亚型很有意义。AD或路易体痴呆（DLB）患者的皮质乙酰胆碱酯酶（AChE）活性明显低于年龄匹配的正常对照组。在路易体痴呆中，多巴胺合成也受损，类似于帕金森病。
