[Magnetic resonance imaging in spinocerebellar degeneration]

Magnetic resonance imaging (MRI) was evaluated in 11 patients with non-familial spinocerebellar degeneration (6 olivo-ponto-cerebellar atrophy (OPCA) and 5 late cortical cerebellar atrophy (LCCA]. MRI was carried out using a superconducting magnet of 0.256 tesla (VISTA-MR) and an inversion recovery pulse sequence of repetition time 2.08 sec and inversion time 0.5 sec. The degree of atrophy was assessed with regard to ponto-cerebellar system (basis pontis and middle cerebellar peduncle) and cerebellum in the sagittal and coronal images. In the mid-sagittal images, the width of ventral pons, dorsal pons, tegmentum and tectum of midbrain, and the height of fourth ventricle were measured. Especially, the degrees of atrophy of basis pontis in the mid-sagittal image and middle cerebellar peduncle in the coronal image were divided into 4 grades and evaluated respectively. On the other hand, atrophy of cerebellum was judged from enlargement of cerebellar fissures and reduction of cerebellar volume in the sagittal and coronal images. Atrophy of ponto-cerebellar system was found in OPCA, but not in LCCA. In OPCA, atrophy of middle cerebellar peduncle in the coronal image, which was likely to begin in an inferior part of pons, was more marked than, or equal to, atrophy of basis pontis in the mid-sagittal image. With regard to cerebellar vermis, the superior faces were more atrophic than the inferior faces in both OPCA and LCCA, but in OPCA, atrophy on the superior faces was dominant in the posterior lobe including declive and folium as against dominance in the anterior lobe in LCCA.(ABSTRACT TRUNCATED AT 250 WORDS)