1. From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110 (M.N., M.J.H., F.W.P., D.H.B., M.Z., C.R., V.M.M.); and Division of Emergency/Trauma Radiology, McMaster University, Hamilton General Hospital, Hamilton, Ontario, Canada (M.N.P.).