1. Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway
2. Department of Pediatrics, St. Olav's University Hospital, NO-7433 Trondheim, Norway
3. Unit for Applied Clinical Research, Faculty of Medicine, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway
4. Department of Anaesthesia and Emergency Medicine, St. Olav's University Hospital, NO-7006 Trondheim, Norway