[Neuroimaging for patients with Alzheimer disease in routine practice]

In routine practice neuroimaging has been applied as an adjunct technique for early and differential diagnosis of Alzheimer disease in routine practice. Of the several neuroimaging modalities, magnetic resonance imaging (MRI) and brain perfusion single-photon emission computed tomography (SPECT) have been commonly used in Japan; further software programs are used to aid statistical analysis of the imaging results. For example voxel-based specific regional analysis system for Alzheimer disease (VSRAD) for MRI and easy Z-score imaging system (eZIS) are used for the analysis of MRI and SPECT. In the early stage of Alzheimer disease, specific findings of regional atrophy and perfusion reduction are observed in some areas. In the posterior cingulate gyrus precuneus and parietal cortex, perfusion reduction was more frequently observed than atrophy. On the other hand, in the medial temporal structures, perfusion reduction was less frequently observed than atrophy. Perfusion reduction in the the posterior cingulate gyrus precuneus and in the parietal cortex was more prominent in the case of patients with early-onset Alzheimer disease than in the case of patients with late-onset Alzheimer disease. Further, atrophy in the medial temporal structures was more prominent in the case of patients with late-onset Alzheimer disease than in the case of those with early-onset Alzheimer disease. These findings are helpful for differentiating of Alzheimer disease from other diseases characterized by dementia.