1. From the Department of Radiology, University of California, Davis School of Medicine, 4860 Y St, Suite 3100, Sacramento, CA 95817 (M.H.M.); and Department of Radiology, Stanford University School of Medicine, Stanford, Calif (V.L.T., R.L.H., M.J.W., H.M., A.S.C., G.J.B., D.F.).