1. From the Section of Abdominal Imaging, Department of Diagnostic Radiology (A.M.V., K.M.J., G.M.R.) and Department of Radiation Oncology (A.H.K.), University of Texas MD Anderson Cancer Center, 1400 Pressler St, FCT 15.6074, MSC 1182, Houston, TX 77030; and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (C.O.M., R.J.S.).