[1] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Wellman Ctr Photomed, Boston, MA 02114 USA
[2] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Gastrointestinal Unit, Boston, MA 02114 USA
[3] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Dept Dermatol, Boston, MA 02114 USA
[4] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Dept Radiol, Boston, MA 02114 USA
[5] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Dept Pathol, Boston, MA 02114 USA
[6] Harvard Univ, Sch Med, Brigham & Womens Hosp, Dept Gastroenterol, Boston, MA 02115 USA