Basilar artery hypoplasia with persistent fetal circulations misinterpreted as basilar artery occlusion in a non-invasive angiography

A 55-year-old woman presented with acute memory impairment, initially suspected as transient global amnesia.To rule out alternative causes, she underwent diffusion-weighted imaging (DWI) with time-of-flight magnetic resonance angiography (TOF-MRA) and computed tomography angiography (CTA).While the DWI showed no abnormalities, the basilar artery was not visualized in either CTA or TOF-MRA (Fig. 1A andB).Due to the non-visualized basilar artery, she was admitted for further investigation.