1. Department of Gastroenterology, Oncology and Diabetology, Theresienkrankenhaus und St. Hedwigsklinik GmbH, Heidelberg University, Bassermannstr.1, 68165 Mannheim, Germany
2. Department of Medical Statistics, Biomathematics and Information Processing, Mannheim University Hospital, Ludolf-Krehl-Str. 13-17, 68165 Mannheim, Germany
3. Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
4. Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany