1. From the Department of Radiology (P.J.P., P.M.G., B.W.) and the Department of Medicine (N.D.Y., J.M.W.), University of Wisconsin School of Medicine & Public Health, E3/311 Clinical Science Center, 600 Highland Ave, Madison, WI 53792-3252; and Digestive Endoscopy Unit, Nuovo Regina Margherita Hospital, Rome, Italy (C.H.).