1. Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway;
2. Department of Neurosurgery, St Olavs University Hospital, Trondheim, Norway;
3. Department of Neurosurgery, Sahlgrenska University Hospital, Gothenburg, Sweden;
4. Institute of Neuroscience and Physiology, University of Gothenburg, Sahlgrenska Academy, Gothenburg, Sweden;
5. Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway