1. Department of Gastroenterological Surgery Sykehuset Innlandet Hospital Trust Gjøvik Norway
2. Institute of Clinical Medicine University of Oslo Oslo Norway
3. Department of Gastroenterological Surgery Oslo University Hospital The Norwegian Radium Hospital Oslo Norway
4. Department of Digestive Surgery Akershus University Hospital Oslo Norway
5. Hedmark University College Elverum Norway
6. Department of Radiology Oslo University Hospital The Norwegian Radium Hospital Oslo Norway