1. Danish Headache Centre, Department of Neurology, Rigshospitalet, Glostrup, Faculty of Health Sciences University of Copenhagen, Denmark
2. Department of Neurosurgery, Rigshospitalet, Faculty of Health Sciences University of Copenhagen, Denmark
3. Department of Neuro-Radiology, Rigshospitalet, Faculty of Health Sciences University of Copenhagen, Denmark
4. Department of Neuro-pathology, Rigshospitalet, Faculty of Health Sciences University of Copenhagen, Denmark
5. Departments of Pathology and Neurological Surgery, University of California San Francisco (UCSF), USA