Cerebellar and brainstem hypometabolism in olivopontocerebellar atrophy detected with positron emission tomography

Abstract

We studied local cerebral metabolic rates for glucose (lCMRglc) with 18 F-2-fluoro-2-deoxy-D-glucose and positron emission tomography (PET) in 30 patients with olivopontocerebellar atrophy (OPCA) and 30 age-matched control subjects without neurological disease. The diagnosis of OPCA was based on the history and physical findings and on the exclusion of other causes of cerebellar ataxia by means of laboratory investigations. Computed tomographic scans revealed some degree of atrophy of the cerebellum in most patients with OPCA, and many also had atrophy of the brainstem. PET studies in these patients revealed significant hypometabolism in the cerebellar hemispheres, cerebellar vermis, and brainstem in comparison with the normal control subjects. A significant relationship was found between the degree of atrophy and the level of lCMRglc in the cerebellum and brainstem. Nevertheless, several patients had minimal atrophy and substantially reduced lCMRglc, suggesting that atrophy does not fully account for the finding of hypometabolism, lCMRglc was within normal limits for the thalamus and cerebral cortex. The data suggest that PET/lCMRglc may be useful as a diagnostic test in patients with the adult onset of cerebellar ataxia.