Abstract: Objective To investigate the feature of cerebral glucose metabolism of dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Methods Twenty-five DLB patients and Thirty-one PDD patients underwent positron emission tomography(PET) with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) showing glucose metabolism. The region of interest (ROI) was selected from frontal cortex, temporal cortex, parietal cortex, occipital cortex, cerebellum cortex and corpora striata. ¹⁸F-FDG metabolism ratios between various cerebral regions and cerebellum cortex were compared as an indicator of regional cerebral glucose metabolic patterns.Results FDG metabolism ratio of frontal cortex, occipital cortex, parietal cortex, temporal cortex and corpus striatum decreased similarly in DLB and PPD (P>0.05). FDG metabolism ratio of occipital cortex decreased more significantly in DLB than in PDD (P<0.01). The decrease of FDG metabolism in corpus striatum of DLB was symmetric. For patients with PDD, FDG metabolism in corpus striatum contralateral to onset side decreased more significantly than that of corpus striatum ipsilateral to onset side (P<0.05). Conclusion There are similarities and discrepancies in cerebral glucose metabolism between DLB and PDD. These features may be useful in differential diagnosis between these two kinds of Lewy body disease.

Key words: dementia with lewy bodies, Parkinson's disease, dementia, positron emission tomography (PET)