Sensitivity and specificity of positron emission tomography and magnetic resonance imaging studies in Alzheimer's disease and multi-infarct dementia.

Positron emission tomographic (PET) scans using [18F]-fluorodeoxyglucose and magnetic resonance imaging (MRI) scans were quantitatively analyzed for metabolic and structural abnormalities in normal subjects and patients classified as having Alzheimer's disease (AD), mixed dementia and multi-infarct dementia (MID) according to Hachinski ischemic scores. MRI-detected abnormalities in the periventricular white matter and in subcortical locations increased in incidence with age in normals and increased markedly in AD and especially in MID. Upper limits for the severity of these white matter lesions could be defined only for normal young and elderly subjects, but not for AD, mixed or MID patients. PET scan abnormalities occurred in about 90% of demented patients and in 54% of elderly and 34% of young normals. There was no characteristic pattern of abnormality that distinguished MID from AD patients. It is concluded that PET and MRI studies in demented patients are useful ancillary tests especially in evaluating the mild, questionably demented subject and for assessing the functional impact of structural disease.

对正常受试者以及根据哈钦斯基缺血评分被归类为患有阿尔茨海默病（AD）、混合性痴呆和多发性脑梗死性痴呆（MID）的患者，使用[18F]-氟脱氧葡萄糖进行正电子发射断层扫描（PET）以及磁共振成像（MRI），并对代谢和结构异常进行了定量分析。在正常人群中，MRI检测到的脑室周围白质和皮质下部位的异常发生率随年龄增长而增加，在AD患者中显著增加，在MID患者中尤其明显。这些白质病变严重程度的上限只能针对正常的年轻和老年受试者确定，而无法针对AD、混合性痴呆或MID患者确定。约90%的痴呆患者以及54%的老年人和34%的年轻正常人存在PET扫描异常。没有能够区分MID患者和AD患者的特征性异常模式。结论是，对痴呆患者进行PET和MRI研究是有用的辅助检查，特别是在评估轻度、疑似痴呆的受试者以及评估结构性疾病的功能影响方面。