1. Norwegian University of Science and Technology,Department of Circulation and Medical Imaging,Trondheim,Norway
2. Norwegian University of Science and Technology, SINTEF Medical Technology,Department of Circulation and Medical Imaging,Trondheim,Norway
3. Inst. of Clinical Medicine, University of Oslo,Sorlandet Hospital,Kristiansand,Norway
4. Norwegian University of Science and Technology,St. Olavs Hospital,Department of Circulation and Medical Imaging,Trondheim,Norway