1. From the Departments of Radiology (C.L.V., C.P.V., A.C., D.D.C., J.M.H., P.N., F.H.M.), Pathology (T.J.D., G.Y.Y.), and Urology (D.T.O.), Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611.