2D EPI with lot of motion will cause blurring and subtraction artifacts (motion between control and label), noticeable by the pseudo-perfusion high intensity rim. The subtraction artifacts are gone with background suppression, the blurring remains

Subject with not a lot of motion (average 0.2 mm/frame, no motion spikes), still notice the high intensity rim from “pseudo-perfusion” (i.e. motion between control and label), without background suppression (3T 2D EPI).

Subject with more motion (0.5 mm/frame average motion, 27% of data excluded for motion spikes). Also 3T 2D EPI without background suppression.

In case we do have background suppression (3T 2D EPI): we observe much less pseudo-perfusion high intensity rim artifacts : ( 0.2 mm average motion, 40% excluded motion spikes).

0.5 mm average motion, 26% exclusion motion spikes. Although we observe some motion (as in blurring), we don’t observe the pseudo-perfusion high intensity rim due to the presence of background suppression (again 3T 2D EPI).