1. From the Mallinckrodt Institute of Radiology (D.A.R., D.P., S.B.) and Department of Cardiothoracic Imaging (R.S., C.R., J.M., M.N., A.J.W., M.C.), Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63108; and Department of Radiology, Beaumont Hospital, Dublin, Ireland (S.M.).