The cerebellum in sagittal plane--anatomic-MR correlation: 2. The cerebellar hemispheres.

Thin (5-mm) sagittal high-field (1.5-T) MR images of the cerebellar hemispheres display (1) the superior, middle, and inferior cerebellar peduncles; (2) the primary white-matter branches to the hemispheric lobules including the central, anterior, and posterior quadrangular, superior and inferior semilunar, gracile, biventer, tonsil, and flocculus; and (3) several finer secondary white-matter branches to individual folia within the lobules. Surface features of the hemispheres including the deeper fissures (e.g., horizontal, posterolateral, inferior posterior, and inferior anterior) and shallower sulci are best delineated on T1-weighted (short TR/short TE) and T2-weighted (long TR/long TE) sequences, which provide greatest contrast between CSF and parenchyma. Correlations of MR studies of three brain specimens and 11 normal volunteers with microtone sections of the anatomic specimens provides criteria for identifying confidently these structures on routine clinical MR. MR should be useful in identifying, localizing, and quantifying cerebellar disease in patients with clinical deficits.