A relatively compact arteriovenous malformation is located superficially in the parieto-occipital region on the left, measuring 31 x 18 x 32 mm. It receives most of its supply from the left middle cerebral artery branches, with further contribution from the left posterior cerebral artery. No convincing external carotid supply can be demonstrated. Venous drainage appears predominantly (exclusively?) superficial, with a very large vein coursing posteriorly to drain into the superior sagittal sinus. There is no evidence of haemorrhage or thrombosis or aneurysm formation.