1. From the Mallinckrodt Institute of Radiology (K.L.S., K.M.M., S.B., C.A.R.), Department of Internal Medicine, Cardiovascular Division (A.C.B.), Department of Surgery (J.W.O.), and Department of Pathology (C.Y.L.), Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110; and Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Ga (M.N.).