Cross-sectional and longitudinal studies of three-dimensional stereotactic surface projection SPECT analysis in Parkinson's disease

Although dementia is increasingly recognized as a common feature in Parkinson's disease (PD), its pathological substrate remains unknown. We conducted cross-sectional and longitudinal brain perfusion SPECT analyses to explore changes during the course of developing dementia in PD. Fifty-five patients originally diagnosed with PD were imaged in the cross-sectional study. Twenty-one of these, nine without dementia and 12 with dementia (PDD), were included in the longitudinal study to observe perfusion changes during the course of their disease. Data were analyzed using three-dimensional stereotactic surface projection SPECT analysis. The UK Parkinson's Disease Society Brain Bank criteria were used to diagnose PD and the revised criteria for the clinical diagnosis of dementia with Lewy bodies for PDD. The cross-sectional study showed that patients with PDD had significantly reduced perfusion in the right posterior cingulate, the right precuneus and the left posterior cingulate area. In the longitudinal study, significantly reduced perfusion was observed in the left anterior frontal gyrus in PD without dementia, and in the right inferior parietal lobule in those that developed PDD. We suggest that a relationship exists between developing dementia in PDD and reduced perfusion in the posterior parietal area.