Solving the dark-sides of multiband-ASL: A framework to correct for increased motion artefacts in MB-ASL due to sharp transitions in the level of background suppression

Recently, incorporation of multi-band (MB-) EPI into ASL has been reported, enabling increased spatial coverage without compromising SNR of distal slices due to longer post-labeling delay time. However, the combination of MB-EPI and ASL with the background suppression (BGS) could potentially induce problems when motion correction (MoCo) is required. In this study, we demonstrate that subtraction artefacts can be introduced when performing MoCo of MB-BGS-pCASL and that these artefacts can degrade image quality considerably. We propose a new framework that corrects for image degradation caused by MoCo of MB-BGS-pCASL data, thereby greatly improving robustness and thus usefulness of MB-BGS-pCASL.