Persistent primitive olfactory artery associated with accessory middle cerebral artery and partially duplicated...

Although anatomical variations in the anterior cerebral artery (ACA), anterior communicating artery (ACoA) complex, and/or middle cerebral artery (MCA) are common, their combination is rare. Persistent primitive olfactory artery (PPOA) is a rare variant of the proximal ACA that has a hairpin curve associated with cerebral aneurysms. To our knowledge, there are no previous reports of PPOA associated with accessory MCA and partially duplicated ACoA.

We report a case of PPOA with a suspected aneurysm at the hairpin curve associated with accessory MCA and partially duplicated ACoA, diagnosed by 1.5-Tesla magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA).

A 46-year-old woman visited our hospital for screening examinations for cerebrovascular disease. MRA showed hairpin curves in the proximal portions of the bilateral ACAs, which we considered to be bilateral PPOAs (type 1). MRA three-dimensional volume rendering images revealed a small bulge, a suspected aneurysm, at the left hairpin curve. MRI/MRA showed that the left accessory MCA originated just proximal to the bulge in the hairpin curve. A partial duplication of the ACoA was also observed. We plan to follow up on the bulge in the hairpin curve because of the increased risk of aneurysm formation.

Careful imaging assessment is important to identify rare anatomical variations. MRA three-dimensional volume rendering images provided a better understanding of the vascular structure, including the presence of a small bulge suspected to be an aneurysm. In our case, accessory MCA was considered to enhance local hemodynamic stress at the hairpin curve.