1. From the Department of Radiology, Columbia University, New York-Presbyterian/Lawrence Hospital, 622 W 168th St, PB-1-301, New York, NY 10032 (K.A.V.); Department of Surgery, Urology Division, City of Hope, Duarte, Calif (S.A.C.); Departments of Radiology (L.S., S.S.R.) and Surgery, Urology Division (S.R.), University of California, Los Angeles, Los Angeles, Calif; and Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, Calif (N.K.).