Spinocerebellar ataxias.

Conventional MRI in patients presenting with progressive ataxia demonstrates the three main patterns of macroscopic damage, namely spinal atrophy, olivopontocerebellar atrophy and cortical cerebellar atrophy. Moreover it contributes to the diagnosis of fragile-X tremor ataxia syndrome and siderosis of the CNS. Non conventional MRI techniques detect nervous tissue abnormalities before development of atrophy which are correlated with the severity of the clinical deficit.