Combined duplicate origin and early bifurcated middle cerebral artery diagnosed by magnetic resonance angiography

To describe a case of combined duplicate origin and early bifurcated middle cerebral artery (MCA) incidentally diagnosed using magnetic resonance (MR) angiography.

A 51-year-old woman with an unruptured left MCA aneurysm underwent cranial MR angiography with a 3-Tesla scanner for presurgical evaluation. MR angiography was performed using a standard 3-dimensional time-of-flight technique.

An unruptured left MCA aneurysm at the M1-M2 junction was identified. The maximum aneurysm diameter was 9 mm. Two almost equally sized right MCAs arose from the terminal segment of the right internal carotid artery. These two channels soon anastomosed, and the temporal branch arose from the inferior channel. The aneurysm was successfully treated with coil embolization.

We herein report a case of a combined duplicate origin and early bifurcated MCA. This variation can also be regarded as anastomosis between the main MCA and the duplicated MCA. This variation has been previously reported as segmental duplication of the MCA. This is the third case of this rare MCA variation reported in the relevant English-language literature. The term “segmental duplication” may be confused with duplicate origin of the MCA, in which only one artery is located distal to the fusion.