Middle cerebral artery variations: duplicated and accessory arteries.

PURPOSE Our goal was to analyze the anatomic similarity between the duplicated middle cerebral artery (MCA) and the accessory MCA and their relationship to the early branches of the MCA.

METHODS We reviewed stereoscopic angiograms of duplicated MCAs in four patients and accessory MCAs in four patients with reference to the origin, size, and cortical supply of these anomalous vessels, along with the presence of perforating arteries and the recurrent artery of Heubner (RAH).

RESULTS The duplicated MCAs supplied the cortical territory of the temporopolar and the anterior temporal and/or middle temporal arteries. The accessory MCAs supplied the cortical territory of the orbitofrontal and/or prefrontal arteries. The duplicated MCAs had perforating arteries in three of four cases and coexisted with the RAH in three of four cases, whereas the main MCA had perforating arteries in all four cases. The accessory MCA had perforating arteries in all four cases and coexisted with the RAH in three of four cases, whereas the main MCA had perforating arteries in one of four cases.

CONCLUSION A consistent cortical supply by the duplicated MCA and the accessory MCA to the anterior temporal lobe and the anterior frontal lobe, respectively, and its similarity to the cortical supply by the early branches of the MCA suggest that development of duplicated and/or accessory MCAs is an anomalously early ramification of the early branches of the MCA.