1. From Duke Cardiovascular Magnetic Resonance Center (B.S., M.D.E., L.M.H., T.S.E.A., I.K., W.G.R., M.A.P., R.M.J., R.J.K.), Department of Medicine (B.S., M.D.E., T.S.E.A., I.K., M.A.P., R.M.J., R.J.K.), and Department of Radiology (L.M.H., R.M.J., R.J.K.), Duke University Medical Center, Durham, NC; and Siemens Medical Solutions, Chicago, Ill (W.G.R.).