33 years, Male, memory problems, dementia. Brain parenchymal volume is within normal limits. There is no intracranial mass. There is ectopia of the cerebellar tonsils, right greater than left, with peglike configuration and measuring up to 17 mm below the foramen magnum. There is associated mild crowding at the foramen magnum. A left frontal developmental venous anomaly is incidentally noted. Brain parenchyma is otherwise unremarkable with no focal signal abnormality. Bilateral hippocampi are unremarkable. No evidence of ischemia or hemorrhage. No hydrocephalus. No extra-axial collections. No abnormal parenchymal or meningeal enhancement. Major flow-voids are preserved. There is minimal mucosal thickening in the paranasal sinuses and mucous retention cysts involving the maxillary sinuses, right larger than left. Bone marrow signal and extracranial soft tissues are unremarkable.
Incidentally seen are findings compatible with Chiari 1 malformation with mild associated crowding at the foramen magnum. Brain parenchyma appears otherwise within normal limits.