Hydrocephalus in leptomeningeal disease

FLAIR imaging at baseline (A) and at the time of diagnosis of leptomeningeal metastases (B). The image in panel A demonstrates normal ventricular size (arrow). The image in panel B demonstrates new hydrocephalus, with ventricular enlargement (arrowhead) and periventricular hyperintensity (arrows) consistent with transependymal flow of cerebrospinal fluid.