Figure 9c. Giant VR spaces in the mesencephalothalamic region in a 19-year-old man. (a, b) Axial (a) and sagittal (b) T2-weighted images (5970/120) show a multicystic lesion in the mesencephalothalamic region. The lesion extends from the left cerebral peduncle to the left thalamus. The content of the cysts is CSF-like. The adjacent brain parenchyma has normal signal intensity. No solid components are identified. (c) Axial gadolinium-enhanced T1-weighted image (478/18) shows no enhancement. The process has caused obstruction of the sylvian aqueduct, resulting in hydrocephalus. The size of the lesion and the degree of hydrocephalus were unchanged compared with the appearance on MR images obtained 2 years earlier.