1. From Cardiovascular Magnetic Resonance Laboratories (S.D.C., S.J.L., P.B., M.P.W., T.A.W., K.A.L., S.A.W.), Barnes-Jewish Hospital at Washington University School of Medicine; the Department of Biomedical Engineering (S.D.C., S.A.W.), Washington University, St Louis, Mo; and Philips Medical Systems (S.D.C.), Best, Netherlands.