[Clinical types of spinocerebellar degeneration and evaluation with MR imaging].

Eighty one patients with the clinical diagnosis of non-hereditary or hereditary spinocerebellar degeneration were examined by magnetic resonance imaging (MRI). The MRI findings were subdivided into non-cerebellar atrophy, cerebellar atrophy without and with apparent enlargement of the fourth ventricle as a result of atrophy of the middle or superior cerebellar peduncles. The first pattern of non-cerebellar atrophy included ataxias such as Friedreich's ataxia and Machado-Joseph disease (MJD; type II). In the patients with MJD, atrophy of the brainstem was frequently recognized. The second pattern largely included late cortical cerebellar atrophy and hereditary ataxia of Holmes type. The third pattern was subdivided further into atrophies of the middle and superior cerebellar peduncles. The pattern of the former included olivo-ponto-cerebellar atrophy (OPCA) and hereditary ataxia of Menzel type, and the pattern of the latter included MJD and dentato-rubro-pallido-luysian atrophy (DRPLA). In the patients with OPCA and hereditary ataxia of Menzel type, increased signal intensity on T2-weighted image was always observed in the transverse pontine fibers, middle cerebellar peduncles. In several patients with MJD and DRPLA, atrophy of both cerebellar peduncles was demonstrated, but abnormal signal intensity was not observed in the pontocerebellar areas.