Cerebral blood flow in spinocerebellar degenerations: a single photon emission tomography study in 28 patients.

We used single photon emission tomography to study regional cerebral perfusion in patients with different forms of spinocerebellar degeneration: 6 patients with Friedreich's ataxia (FA), 6 with early-onset cerebellar ataxia with retained tendon reflexes (EOCA), 5 with autosomal dominant cerebellar ataxia type 1 (ADCA I) and 11 with idiopathic late-onset cerebellar ataxia (ILOCA). The results were related to clinical and magnetic resonance imaging (MRI) findings. Cerebellar hypoperfusion was constant in ADCA I and frequent in patients with other spinocerebellar degenerations. Brain stem hypoperfusion was constant in ADCA I, frequent in ILOCA patients with pontocerebellar atrophy and absent in FA and EOCA. FA and EOCA often showed a reduction in the parietotemporal cortex blood flow, which was not related to cortical atrophy. ILOCA patients had an asymmetric pattern in the temporal areas with decreased blood flow in the right side only. Caudate hypoperfusion was found in ADCA I patients. Cerebral atrophy did not account for changes in regional blood flow, which probably indicate early involvement of cerebral structures.