28-year-old male with medulloblastoma and altered mental status. Please evaluate for new mass effect/edema. Midline suboccipital craniectomy is noted. There is ex vacuo dilatation of the fourth ventricle that is similar in appearance to prior MRI. Encephalomalacia of the cerebellum as well as enlarged supratentorial ventricular size also remain unchanged.There is no evidence of intracranial hemorrhage; no new masses.Shunt tubing enters right lateral ventricle through right frontal skull. The calvaria and skull base are otherwise radiographically normal. The visualized paranasal sinuses and mastoid air cells are normally pneumatized.
Postoperative changes relatively stable without evidence of new mass. No significant change in ventricular size on comparison to prior MR.