Noninvasive MR imaging of cerebral perfusion in patients with a carotid artery stenosis

Arterial spin labeling (ASL) perfusion MRI with image acquisition at multiple delay times can be used to measure delays in the arrival of arterial blood to the brain. We assessed the effect of a symptomatic internal carotid artery (ICA) stenosis on ASL timing parameters, and evaluated the effect of collateral flow through the circle of Willis.