Temporal branch of the posterior cerebral artery arising from the posterior communicating artery diagnosed by MR angiography.

We report a case in which the temporal branch of the posterior cerebral artery (PCA) arose from the posterior communicating artery (PCoA) and was diagnosed by magnetic resonance (MR) angiography. The PCoA arose from its normal point on the supraclinoid internal carotid artery and fused with the PCA at its normal point of the P1-P2 junction. We believe this is the first report of such a variation. Careful review of MR angiographic images is important to detect rare arterial variations, and partial maximum-intensity-projection images aid their identification on MR angiography.