Dizziness, unsteady gait: progressive imbalance with walking for 6 weeks. History of invasive anorectal carcinoma. There is mild cerebellar volume loss, particularly involving the vermis. There is a subcentimeter linear focus of susceptibility effect in the left pons with slight extension into the cerebral peduncle. There is also patchy T2 hyperintensity throughout the pons. There is also mild scattered cerebral white matter T2 hyperintensity particularly in a periventricular distribution and mild diffuse cerebral volume loss. There is no evidence of mass or acute infarct. There is no abnormal intracranial enhancement. There is a mega cisterna magna. There is no midline shift or herniation. The major cerebral flow voids are intact. The orbits and ears are grossly unremarkable. The skull appears to be intact. There are bilateral lens implants. There is mucosal thickening in the ethmoid sinuses.
1. Nonspecific mild cerebellar volume loss, particularly involving the vermis, and mild diffuse cerebral volume loss. 2. A subcentimeter linear focus of susceptibility effect in the left pons with slight extension into the cerebral peduncle may represent a chronic hemorrhagic lacunar infarct. 3. Patchy T2 hyperintensity throughout the pons and mild scattered cerebral white matter T2 hyperintensity particularly in a periventricular distribution likely represent chronic small vessel ischemic disease4. No evidence of intracranial hemorrhage, mass, or acute infarct. 