Relationship of Alzheimer Disease Severity and ^99mTc-ECD SPECT Brain Blood Flow Imaging

Abstract

There are many reports from brain function image studies of Alzheimer disease (AD) that hypoperfusion of brain blood flow in the parietal-temporal association cortex is a characteristic of AD and that hypoperfusion spreads to the frontal cortex with progress of AD. ^99mTc-ECD SPECT brain blood flow examinations of AD patients ranging from very early stage AD including amnestic mild cognitive impairment (aMCI) that is defined as precursor to AD to severe AD were conducted. The relationship between severity based on mini-mental state examination (MMSE) score and brain blood flow was assessed. Relative hypoperfusion of the posterior cingulate, precuneus, and right hippocampus was observed in very early AD but correlation with AD severity was not observed. However, a positive correlation was observed between the score for MMSE and brain blood flow of the bilateral basal forebrain and orbital gyri. These results suggest that brain blood flow SPECT examination is useful for diagnosis of the stage of AD and predicting the progress of AD.