PATTERNS OF CEREBRAL GLUCOSE-METABOLISM DETECTED WITH POSITION EMISSION TOMOGRAPHY DIFFER IN MULTIPLE SYSTEM ATROPHY AND OLIVOPONTOCEREBELLAR ATROPHY

We used positron emission tomography with [F-18]fluorodeoxyglucose to study local cerebral metabolic rates for glucose (1CMRglc) in patients with multiple system atrophy (MSA), sporadic olivopontocerebellar atrophy (sOPCA), and dominantly inherited olivopontocerebellar atrophy (dOPCA) in comparison with normal control subjects. In MSA, absolute 1CMRglc was significantly decreased in the brainstem, cerebellum, putamen, thalamus, and cerebral cortex. In sOPCA, absolute 1CMRglc was significantly decreased in the brainstem, cerebellum, putamen, thalamus, and cerebral cortex. In sOPCA, absolute 1CMRglc was significantly decreased in the brainstem and cerebellum but not in the other structures. Examination of 1CMRglc normalized to the cerebral cortex in comparison with normal controls revealed in MSA significant decreases in the brainstem, cerebellum, and putamen but, in both sOPCA and dOPCA, significant decreases only in the brainstem and cerebellum. The findings indicate that these three disorders all show a marked decrease of 1CMRglc in the brainstem and cerebellum but differ in the degree of hypometabolism in forebrain and cerebral cortical structures. The results are consistent with the possibility that, in many cases, sOPCA will evolve into MSA. Moreover, positron emission tomography may provide helpful diagnostic information in these neurodegenerative diseases.