Arterial spin labeling MRI

ASL was invented pre-clinically in 19901. The first human applications appeared in 1996 when the post-labeling delay (PLD) was introduced to compensate for the larger distance between labeling in the neck and readout in the brain2. The initially low clinical reliability improved with the implementation of background suppression in 19993,4, the increasing availability of 3T MRI, and the invention of pseudo-continuous ASL in 20085. In 2012, the European COST-action BM1103 "ASL In Dementia” was founded and worked towards reducing the ASL differences between MRI scanners to improve between-center reproducibility. Together with other ISMRM ASL investigators, this resulted in the 2014 consensus paper that recommended single-PLD PCASL with a 3D readout, background suppression, no vascular crushing, the acquisition of a separate M0 image, and a simplified single-compartment quantification model for clinical ASL6.