[Study of patients with spinocerebellar degeneration using positron emission tomography]

We studied cerebral blood flow, oxygen metabolism and their relation to clinical symptoms in 45 patients with spinocerebellar degeneration (SCD) and 12 normal control subjects using positron emission tomography (PET). Regions of interest were acquired for the cerebellar hemispheres, cerebellar vermis, brainstem, thalami, and cerebral cortices. PET studies in these patients revealed that regional cerebral blood flow (CBF), regional cerebral oxygen metabolic rate (CMRO2), CBF/mean CBF of each cerebral cortex (CBF/mCBF) and CMRO2/mean CMRO2 of each cerebral cortex (CMRO2/mCMRO2) in the cerebellar hemispheres, cerebellar vermis, and brainstem showed a significant decrease in comparison with the normal control subjects, while in the cerebral cortices and thalami, SCD patients showed normal values. CBF/mCBF and CMRO2/mCMRO2 were significantly decreased in patients with olivopontocerebellar atrophy (OPCA) and Menzel type of hereditary ataxia (Menzel type) in the cerebellar hemispheres, cerebellar vermis, and brainstem, whereas patients with late cortical cerebellar atrophy (LCCA) and Holmes type of hereditary ataxia (Holmes type) revealed a significant decrease of CBF/mCBF and CMRO2/mCMRO2 in the cerebellar hemispheres and cerebellar vermis, but not in the brainstem. Patients with OPCA showed a significant decrease of CBF in the cerebellar hemispheres, cerebellar vermis, brainstem and that of CMRO2 in the cerebellar hemispheres and cerebellar vermis. Patients with LCCA showed a significant decrease of CBF in the right cerebellar hemisphere and cerebellar vermis. However, a significant reduction of CBF and CMRO2 was not observed in patients with Menzel type or Holmes type in these regions. In patients with LCCA and Holmes type, the severity of upper limb ataxia and dysdiadochokinesis were significantly correlated with CBF/mCBF and CMRO2/mCMRO2 in the cerebellar hemispheres and brainstem.(ABSTRACT TRUNCATED AT 250 WORDS)