[1] University of Bergen,Department of Clinical Medicine
[2] Haukeland University Hospital,Department of Medicine, National Centre for Ultrasound in Gastroenterology
[3] Voss Hospital,Department of Medicine
[4] University of Bergen,Department of Clinical Science
[5] LHL-clinics Bergen,Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication
[6] Brno University of Technology,undefined
[7] Institute of Scientific Instruments of the Czech Academy of Sciences,undefined