1. Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.
2. Department of Medical Imaging, St. Olav's Hospital, Trondheim, Norway.
3. Department of Neuromedicine, Norwegian University of Science and Technology, Trondheim, Norway.
4. Department of Physical Medicine and Rehabilitation, St. Olav's Hospital, Trondheim, Norway.