1. Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan;
2. Faculty of Health Sciences, Hokkaido University, Sapporo, Japan;
3. Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Sapporo, Japan;
4. Department of Neurosurgery, Sapporo Azabu Neurosurgical Hospital, Sapporo, Japan;
5. Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, Niigata, Japan;
6. Department of Neurosurgery, Kashiwaba Neurosurgical Hospital, Sapporo, Japan;
7. Department of Clinical Neurosciences and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada