1. Interdisciplinary Center of Ultrasound, University Hospital Giessen and Marburg, Marburg, Germany;
2. Department of Haematology, Oncology and Immunology, University Hospital Giessen and Marburg, Philipps University Marburg, Marburg, Germany;
3. Department of Gastroenterology and Gastrointestinal Oncology, University Medical Centre Göttingen, Göttingen, Germany;
4. Department of General Practice and Family Medicine, Philipps University, Marburg, Germany