Reason: Rule out posterior circulation stroke. Evaluate centrum semiovale CT hyperintensity for hemorrhage or tumor. History: Sudden onset unsteadiness, vomiting, vertical nystagmus. There is no evidence of acute infarct. There is a lesion with substantial susceptibility effect and central T1 hyperintensity in the right posterior centrum semiovale that measures up to 10 mm. There is no surrounding edema or abnormal enhancement. There are a few scattered punctate foci of nonspecific cerebral white matter T2 hyperintensity. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The major cerebral flow voids are intact. The orbits, skull, paranasal sinuses, and scalp soft tissues are grossly unremarkable.
A lesion in the right posterior centrum semiovale that measures up to 10 mm likely represents a cavernous malformation. No evidence of developmental venous anomaly, acute hemorrhage, or acute posterior circulation infarction.