Bilateral Type II Persistent Proatlantal Intersegmental Arteries

Abstract

A 64-year-old man with treated hypertension presented with acute left arm and leg weakness. A brain magnetic resonance imaging (MRI) and neck magnetic resonance angiography (MRA) were performed. There was restricted diffusion in the right internal capsule posterior limb consistent with an acute lacunar infarct. The MRA demonstrated aplastic bilateral cervical vertebral arteries (V1 and V2 segments). bilaterally, a variant artery arose from the external carotid just above its origin, extended superiorly then medially, and forming the vertebral artery (V3 and V4 segments). bilaterally, the occipital artery arose from the variant artery at the juncture where it turned medially. The right variant artery terminated intracranially in the right posterior inferior cerebellar artery. The left variant artery continued intracranially to supply the basilar. The appearance was consistent with bilateral persistent proatlantal intersegmental arteries (PPIA) type II.