Fig 16.

A, Sagittal SS-FSE T2-weighted image demonstrates a small posterior fossa with displacement of the cerebellar vermis inferiorly, consistent with a Chiari II malformation in a 22-gestational-week-old fetus. The corpus callosum is hypogenetic (arrow). There is diffuse effacement of the subarachnoid spaces, which is typically observed in these cases.

B, Coronal SS-FSE T2-weighted image demonstrates 2 small hypointense nodules (arrows) along the lateral margin of the atrium of the left lateral ventricle, consistent with periventricular nodular heterotopia. The ventricles are enlarged. Findings were confirmed by postnatal MR imaging.