1. From the Division of Abdominal Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, White 270, Boston, MA 02114 (N.C.); Department of Radiology, Oregon Health and Science University/Hospital Dotter Interventional Institute, Portland, Ore (P.L.); and Institute for Diagnostic and Interventional Radiology, University of Cologne, Germany (S.L.).