1. From the Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115 (M.M.H.); Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (C.A.R., S.B.); and Department of Radiology, Duke University School of Medicine, Durham, NC (T.S.H.).