1. Division of Gastroenterology, Department of Medicine, Stord Hospital, Stord, Norway
2. Division of Gastroenterology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
3. National Centre for Functional Gastrointestinal Disorders, Department of Medicine, Haukeland University Hospital, Bergen, Norway
4. National Centre for Ultrasound in Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway