1. Diagnostic Radiology, Great Ormond Street Hospital for Children, London, United Kingdom
2. Institute of Surgical Sciences
3. MRC Centre of Epidemiology for Child Health, UCL Institute of Child Health, London, United Kingdom
4. Departments of Radiology
5. Pediatrics, Haukeland University Hospital, Bergen, Norway
6. Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway