Pseudoaneurysms at aortic cannulation site after coronary artery bypass graft: MR findings. Pseudoaneurysm at the aortic cannulation site is a rare but potentially fatal complication of coronary artery bypass surgery. We present two cases in which MRI provided significant information regarding the anatomy and extent of a pseudoaneurysm. In one case both spin-echo imaging and cine MRI with and without gradient moment nulling (flow compensation) were used. The absence of gradient moment nulling in cine MRI provides additional contrast between flowing and static blood. This contrast may complement conventional cine images with gradient moment nulling, providing further information.