1. From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box 8131, St Louis, MO 63110 (J.C., M.M., M.H.L.); Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Ga (M.Z.); and Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Conn (I.D.d.O.S.).