1. Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Radiology, Berlin, Germany
2. Carl-Thiem-Klinikum, Department of Gastroenterology, Cottbus, Germany
3. Department of Radiology, University Medical Center Regensburg, Regensburg, Germany