Fig. 1From: Arterial spin labeling perfusion MRI applications in drug-resistant epilepsy and epileptic emergencyPrinciples of ASL. A "labeled" image and a "control" image are respectively acquired when the blood-water magnetization is inverted or not. The subtraction of these two images yields a perfusion-weighted image. Permission was granted by Hernandez-Garcia et al. (© Elsevier [14]) to reuse this figureBack to article page