Bilateral carotid-anterior cerebral artery anastomoses associated with bilateral ophthalmic arteries arising from the anastomotic arteries diagnosed by magnetic resonance angiography: a case report.

Rarely, the anterior cerebral artery (ACA) arises from the ophthalmic segment of the internal carotid artery, a condition described as carotid-ACA anastomosis or infraoptic course of the ACA that generally demonstrates right-sided predominance. We diagnosed a case of bilateral anastomoses of the carotid and ACA vessels in which bilateral ophthalmic arteries arose from the origins of the anastomotic vessels using magnetic resonance (MR) angiography. Identification of rare arterial variations on MR angiography requires careful scrutiny of source images, and creation of partial volume-rendering images can aid visualization of detailed anatomic structures.