1. From the Department of Internal Medicine, University of Texas Southwestern Medical Center; 5323 Harry Hines Blvd, Dallas, TX 75390-9169 (A.S.H.); Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, Pa (D.L., L.P., V.M.R.); and Department of Population Medicine, Harvard Pilgrim Health Care Institute, Boston, Mass (D.R.D., J.F.W.).