1. From the Mallinckrodt Institute of Radiology, Washington University in St Louis, 510 S Kingshighway Blvd, Campus Box 8131, St Louis, MO 63110 (P.R.D., H.D.R., S.B., J.A.L., M.I.); Department of Radiology, NYU Winthrop Hospital, Mineola, NY (G.J.F.); and Department of Radiology, University of Washington Medical Center, Seattle, Wash (M.C.M.).