Brain 3D-SSP SPECT analysis in dementia with Lewy bodies, Parkinson's disease with and without dementia, and Alzheimer's disease

OBJECTIVES: Cerebral blood flow was compared among patients with dementia with Lewy bodies (DLB), Parkinson's disease with dementia (PDD), Parkinson's disease without dementia (PD), and Alzheimer's disease (AD) using three-dimensional stereotactic surface projection (3D-SSP) analysis. PURPOSE: We attempt to clarify the difference of reduction pattern on SPECT among patients having DLB, PDD, PD, AD. PATIENTS AND METHODS: Six patients with DLB, 7 patients with PDD who were matched with the DLB patients for age, unified Parkinson's disease rating scale-III (UPDRS-III) score, and degree of cognitive function disorders, 21 patients with PD who were matched with the DLB patients for age, UPDRS-III score, 12 patients with AD who were matched with the DLB patients for age and degree of cognitive function disorders, and 12 control subjects. All patients were examined by N-isopropyl-p123I] iodoamphetamine single photon emission computed tomography (123I-IMP SPECT), and obtained images were analyzed with 3D-SSP using an image-analysis software, iSSP ver. 3.5. RESULTS: Although DLB and PDD showed similar cerebral perfusion reduction pattern at the lateral parietal association and lateral temporal association and precuneus on SPECT by the pixel-by-pixel comparison, greater perfusion reduction was observed in DLB than in PDD. Cerebral perfusion was decreased at the occipital lobe of the DLB patients compared with the AD patients. CONCLUSIONS: The regional pattern of blood flow reduction in the brain was found to be different among DLB, PD, and AD. Greater blood flow reduction was observed in DLB, although DLB and PDD showed similar reduction pattern. These regional differences were considered to suggest different and disease-specific combinations of underlying pathological and neurochemical processes.