Figure 3.

Example case for the potential diagnostic use of arterial transit artifacts (ATA). 34 year-old postpartum female presenting with severe headache and left-sided weakness. Head CT and CT angiogram initially called negative, without evidence of infarction, large vessel occlusion, or proximal stenosis. Subsequent MRI with ASL demonstrated peripheral curvilinear hyperintensities — i.e., ATA — suspicious for diffuse stenoses versus collaterals (a); retrospective review of CT angiogram revealed multifocal stenosis of distal arterial branches (b, yellow arrows) raising concern for reversible cerebral vasoconstriction syndrome (RCVS). Conventional angiography corroborated the CTA findings of stenosis (c), which reversed after administration of calcium channel blockers (verapamil) (d), thus confirming RCVS diagnosis. In (a) perfusion maps are shown.