Hypoplasia or stenosis: Usefulness of high-resolution MRI.

Background: Hypoplastic basilar (BA) and vertebral arteries (VA) can cause posterior circulation infarctions. Distinction between hypoplastic and atherosclerotic BA can be difficult with usual angiographic methods (MR, CT or conventional angiographies), only showing arterial luminogram. High-resolution MRI (HRMRI) of the arterial wall is promising in identifying intracranial artery plaques.

Methods: A 70-year-old man with vascular risk factors suddenly presented with vertigo. MRI showed no brain infarction. Contrast-enhanced MRA showed small and irregular BA lumen compatible with severe atherosclerotic stenosis. An associated persistent primitive trigeminal artery was noticed. HRMRI of the BA rectified the initial angiographic diagnosis by showing a normal vessel wall without any thickening that could suggest atherosclerotic plaque.

Conclusions: In the event of BA lumen narrowing, HRMRI may help distinguish between hypoplastic and atherosclerotic artery.