1. Division of Digestive and Liver Diseases, Columbia University Irving Medical Center, New York City, New York
2. Gastroenterology Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
3. University of Maryland Medical System, Baltimore, Maryland
4. Department of Radiology, University of Florida, Gainesville, Florida
5. Department of Pathology, Beth Israel Deaconess Hospital, Boston, Massachusetts
6. Division of Gastroenterology and Hepatology, University of Florida, Gainesville, Florida, USA