[1] Univ Calif San Diego, Dept Med, San Diego, CA 92103 USA
[2] Thomas Jefferson Univ Hosp, Dept Radiol, Philadelphia, PA 19107 USA
[3] Imperial Coll, London, England
[4] Kings Coll London, London, England
[5] Caritas Krankenhaus, Innere Med 2, Bad Mergentheim, Germany
[6] Univ Toronto, Dept Med Imaging, Toronto, ON, Canada
[7] Dept Med & Surg Sci, Div Internal Med, Bologna, Italy
[8] Stanford Univ, Dept Radiol, Stanford, CA 94305 USA
[9] Univ Calgary, Radiol & Med, Div Gastroenterol, Calgary, AB, Canada
[10] Univ Calif San Diego, Radiol, San Diego, CA 92103 USA
[11] Massachusetts Gen Hosp, Radiol, Boston, MA 02114 USA