1. Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis, MO, USA
2. Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
3. Department of Radiology, Yale School of Medicine, New Haven, CT, USA
4. Division of Gastroenterology, Washington University School of Medicine, Saint Louis, MO, USA
5. Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
6. Department of Radiology, University of Arizona College of Medicine, Tucson, AZ, USA
7. Department of Radiology, The University of Alabama at Birmingham, Birmingham, AL, USA
8. Department of Radiology, Medical College of Virginia / Virginia Commonwealth Medical Center, Richmond, VA, USA