Differentiation of early-stage Alzheimer's disease from other types of dementia using brain perfusion single photon emission computed tomography with easy Z-score imaging system analysis.

INTRODUCTION: We performed brain perfusion single photon emission computed tomography (SPECT) to evaluate computer-assisted automated discrimination of early Alzheimer's disease (AD) from other types of dementia using the easy Z-score imaging system (eZIS). SUBJECTS AND METHODS: eZIS analysis of brain perfusion SPECT images was used in patients with early AD, vascular dementia (VD), mixed dementia (VD + AD), frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), and normal controls. Significant changes in regional cerebral blood flow (rCBF) in the volume of interest were assessed in the posterior cingulate gyrus, precuneus and parietal cortices; the severity and extent of decreases in rCBF and the ratio of the extent of the decrease in rCBF to the decrease in whole-brain blood flow (rCBF ratio) were determined.
RESULTS: The severity of the decrease in rCBF in AD patients was significantly greater than in VD and FTD patients and controls. The extent of the decrease in rCBF in AD patients was significantly greater than in FTD patients and controls. The rCBF ratio in AD patients was higher than in VD and FTD patients and controls.
CONCLUSION: The eZIS indices, especially the rCBF ratio, may be useful in establishing the differential diagnosis between early-stage AD and FTD or VD, but the differentiation of AD from VD + AD or DLB remains difficult. Copyright 2008 S. Karger AG, Basel.