1 Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
2 St. Olavs Hospital, Department of Anaesthesiology and Intensive Care Medicine, Trondheim, Norway.
3 Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology (NTNU),Trondheim, Norway.