FIG 1. MR findings in a 4-year-old boy with hypotonia, nystagmus, ataxia, and psychomotor retardation.

A, T2-weighted transverse image (3000/100/2 [TR/TE/excitations]) of the inferior cerebellum shows fusion of the cerebellar hemispheres (arrowhead) and dysplastic, vertically oriented, folial-like structures instead of the normally horizontal folia.

B, Coronal T2-weighted image (3000/100/2) shows multifocal cystic lesions in the superior cerebellar hemispheres (arrowhead), a continuous thin layer of white matter (arrow), and a left periventricular leukomalacia.

C, Sagittal T2-weighted image (3000/100/2) shows a small cerebellar vermis (arrowheads).

D, Three-dimensional, fat-saturation, spoiled gradient-echo, surface shaded display image (50/6/1) shows vertically oriented folia.