1. From the Department of Diagnostic Radiology and Nuclear Medicine (T.J.Y., U.B., D.D.) and Division of Orthopaedic Traumatology (A.B., J.N., R.O.), R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, 22 S Greene St, Baltimore, MD 21201; and Department of Epidemiology and Public Health, University of Maryland School of Medicine (Y.L.).