Matsuda Hiroshi
Department of Nuclear Medicine, Saitama Medical School Hospital, Saitama, Japan.
Neuropathology. 2007 Dec;27(6):570-7. doi: 10.1111/j.1440-1789.2007.00794.x.
The main purposes of neuroimaging in Alzheimer's disease (AD) have been moved from diagnosis of advanced AD to diagnosis of very early AD at a prodromal stage of mild cognitive impairment, prediction of conversion from mild cognitive impairment (MCI) to AD, and differential diagnosis from other diseases causing dementia. Structural MRI studies and functional studies using F-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) and brain perfusion single-photon emission computed tomography (SPECT) are widely used in diagnosis of AD. Outstanding progress in diagnostic accuracy of these neuroimaging modalities has been obtained using statistical analysis on a voxel-by-voxel basis after spatial normalization of individual scans to a standardized brain-volume template instead of visual inspection or a conventional region of interest technique. In a very early stage of AD, this statistical approach revealed gray matter loss in the entorhinal and hippocampal areas and hypometabolism or hypoperfusion in the posterior cingulate cortex and precuneus. These two findings might be related in view of anatomical knowledge that the regions are linked through the circuit of Papez. This statistical approach also offers prediction of conversion from MCI to AD. Presence of hypometabolism or hypoperfusion in parietal association areas and entorhinal atrophy at the MCI stage has been reported to predict rapid conversion to AD.
阿尔茨海默病（AD）神经影像学的主要目的已从晚期AD的诊断转变为轻度认知障碍前驱期极早期AD的诊断、预测轻度认知障碍（MCI）向AD的转化以及与其他导致痴呆的疾病进行鉴别诊断。结构磁共振成像（MRI）研究以及使用F-18氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）和脑灌注单光子发射计算机断层扫描（SPECT）的功能研究广泛应用于AD的诊断。在将个体扫描图像空间标准化到标准化脑容量模板后，基于体素逐个进行统计分析，而不是通过视觉检查或传统的感兴趣区域技术，这些神经影像学检查方法在诊断准确性方面取得了显著进展。在AD的极早期阶段，这种统计方法揭示了内嗅区和海马区的灰质丢失以及后扣带回皮质和楔前叶的代谢减退或灌注不足。鉴于这些区域通过帕佩兹环路相连的解剖学知识，这两个发现可能存在关联。这种统计方法还能预测MCI向AD的转化。据报道，MCI阶段顶叶联合区存在代谢减退或灌注不足以及内嗅区萎缩可预测快速转化为AD。
