1. From the Department of Radiology, Stanford University School of Medicine, Stanford University Medical Center, 725 Welch Rd, Room 1675, Stanford, Calif 94305-5913 (M.C.C., N.M., D.B.L., C.P.L., M.P.L.); Stanford Center for Biomedical Informatics Research, Stanford University, Stanford, Calif (R.L.B., L.Y.); Department of Bioinformatics, University of Utah Medical Center, Salt Lake City, Utah (B.E.C.); and Department of Radiology, Duke University Medical Center, Durham, NC (T.J.A.).