1. Department of Gastroenterology and Hepatology University Hospital Zurich Zurich Switzerland
2. Department of Pathology University Hospital Zurich Zurich Switzerland
3. Department of Visceral Surgery and Medicine Inselspital, Bern University Hospital, University of Bern Bern Switzerland
4. Institute of Epidemiology, Biostatistics and Prevention University of Zurich Zurich Switzerland
5. Department of Radiology Brigham and Women's Hospital and Harvard Medical School Boston Massachusetts USA
6. Institute of Diagnostic and Interventional Radiology University Hospital Zurich Zurich Switzerland
7. Division of Gastroenterology &Hepatology Triemli Hospital Zurich Switzerland
8. Department of Medicine II Saarland University Medical Center, Saarland University Homburg Germany