Relationship of Distal Anterior Cerebral Artery Aneurysm Arising from the Supracallosal Portion and Accessory Anterior Cerebral Artery

Median artery of the corpus callosum(MACC)refers to the median artery of the triplicate anterior cerebral artery(ACA). When MACC distributes to one or to both hemispheres, it is known as the accessory ACA. We performed detailed angiographic analysis of 32 consecutive patients operated upon for distal ACA(DACA)aneurysms, and noted that all DACA aneurysms occurring in the supracallosal portion were accompanied by an accessory ACA as vascular malformation. Such relationship between accessory ACA and DACA aneurysm in the supracallosal portion has not been previously reported.