[1] Washington Univ, Sch Med, Mallinckrodt Inst Radiol, 510 S Kingshighway Blvd,Campus Box 8131, St Louis, MO 63110 USA
[2] Washington Univ, Sch Med, Dept Pathol, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Div Gastroenterol Hepatol & Nutr, St Louis, MO 63110 USA