Mielke R, Heiss W D
Max-Planck-Institut für neurologische Forschung, Köln, Federal Republic of Germany.
J Neural Transm Suppl. 1998;53:237-50. doi: 10.1007/978-3-7091-6467-9_21.
In mild or atypical cases of Alzheimer's disease (AD) the differential diagnosis to other dementing diseases, such as vascular dementia (VD), may pose a difficult problem. Beside computed tomography (CT) and magnetic resonance imaging (MRI), functional neuroimaging by positron emission tomography (PET) support the clinical diagnosis by visualizing cerebral function. PET of 18F-2-fluoro-2-deoxy-D-glucose (FDG) for measurement of regional cerebral glucose metabolism (rCMRGl) has shown a typical metabolic pattern in patients with probable AD: hypometabolism in temporoparietal and frontal association areas, but relative recessing of primary cortical areas, basal ganglia and cerebellum. In VD a different pattern is seen. It consists of scattered areas with reduction of rCMRGl typically extending over cortical and subcortical structures. Severity of dementia is correlated with rCMRGl reduction in the temporoparietal association cortex, irrespective of the cause of dementia. Also the total volume of hypometabolic regions is related to severity of dementia but did not differ between AD and VD, even in patients with small lacunar infarction. This indicates that the total volume of functional tissue loss is more important since it also includes the effects of incompletely infarcted tissue and morphologically intact but deafferented cortex. The characteristic metabolic pattern has a high diagnostic accuracy for the discrimination between probable AD, normals and VD, even in patients with mild cognitive impairment. Under clinical and therapeutic aspects the analysis of longitudinal changes of rCMRGl has shown that neuropsychological and metabolic changes are closely related in both, AD and VD.
在阿尔茨海默病（AD）的轻度或非典型病例中，与其他痴呆性疾病（如血管性痴呆（VD））进行鉴别诊断可能是个难题。除了计算机断层扫描（CT）和磁共振成像（MRI）外，正电子发射断层扫描（PET）功能神经成像通过可视化脑功能来支持临床诊断。用于测量局部脑葡萄糖代谢（rCMRGl）的18F-2-氟-2-脱氧-D-葡萄糖（FDG）PET已显示出可能患有AD的患者的典型代谢模式：颞顶叶和额叶联合区代谢减低，但初级皮质区、基底神经节和小脑相对不受影响。在VD中则可见不同的模式。它由rCMRGl降低的散在区域组成，通常延伸至皮质和皮质下结构。痴呆的严重程度与颞顶叶联合皮质的rCMRGl降低相关，与痴呆的病因无关。代谢减低区域的总体积也与痴呆的严重程度相关，但在AD和VD之间没有差异，即使在有小腔隙性梗死的患者中也是如此。这表明功能性组织损失的总体积更重要，因为它还包括不完全梗死组织和形态学上完整但传入神经阻滞的皮质的影响。即使在轻度认知障碍患者中，特征性代谢模式对鉴别可能的AD、正常人及VD也具有较高的诊断准确性。在临床和治疗方面，对rCMRGl纵向变化的分析表明，AD和VD患者的神经心理学和代谢变化密切相关。
