Arterial spin label imaging of acute ischemic stroke and transient ischemic attack

Since acute stroke and transient ischemic attack (TIA) are disruptions of brain hemodynamics, perfusion neuroimaging might be of clinical utility. Recently, arterial spin labeling (ASL), a noncontrast perfusion method, has become clinically feasible. It has advantages compared to contrast bolus perfusion-weighted imaging (PWI) including lack of exposure to gadolinium, improved quantitation, and decreased sensitivity to susceptibility and motion. Drawbacks include reduced signal-to-noise and high sensitivity to arterial transit delays. However, this sensitivity can enable visualization of collateral flow. This article discusses ASL findings in patients with acute stroke and TIA, focusing on typical appearances, common artifacts, and comparisons with PWI.