Compared to standard two-dimensional (2D) arterial spin labeling (ASL), simultaneous multi-slice (SMS) ASL imaging techniques can reduce T1 relaxation effect of the label; improve spatial coverage and resolution. However, existing 2D SMS ASL techniques are sub-optimal for the background suppression (BS) technique since multiple SMS excitations are required. In this study, we propose a novel constrained slice-dependent BS scheme for 2D multi-slice pseudo-continuous ASL (pCASL) with SMS-EPI acquisition, to suppress background signal across a wide range of T1s. In vivo experiment showed that the BS scheme can increase temporal SNR of perfusion images 1.5-2 folds.
