Fig 3. Axial CT scan (A) showing an occipital hematoma in a 23-year-old man. Anteroposterior (B) and lateral (C) views of the right carotid angiogram showing a right occipital BAVM. There was agreement for the Spetzler-Martin grade, including the size, eloquence, venous drainage, as well as for the presence of a paranidal aneurysm responsible for hemorrhage. However, interobserver disagreement was about the precise location of the aneurysm, either on the feeding artery or into the nidus.