Affiliation: | (1) Department of Gastroenterology, St. Elizabeth's Hospital, 736 Cambridge Street, 02135 Boston, MA, U.S.A.;(2) Department of Radiology, St. Elizabeth's Hospital, 736 Cambridge Street, 02135 Boston, MA, U.S.A.;(3) Department of Radiology, Boston V. A. Medical Center, Boston, MA, U.S.A. |