1. From the Departments of Radiology (D.Z.R., I.P., D.T., H.L., J.B., J.R., N.M.R., D.N.C.) and Urology (I.P., K.G., X.M., C.G.R., D.N.C.), University of Texas Southwestern Medical Center, 2201 Inwood Rd, Dallas, TX 75390; and Department of Radiology, University of Texas MD Anderson Cancer Center, Houston, Tex (A.D.d.L.).