1. Department of Neurosurgery, Nordstadt Hospital, Hannover, Germany
2. Institute of Neuropathology, Faculty of Medicine, University Duisburg-Essen, University Hospital Essen, Germany
3. Institute of Neuroradiology, Faculty of Medicine, University Duisburg-Essen, University Hospital Essen, Germany
4. Department of Neurosurgery, University Duisburg-Essen, University Hospital Essen, Germany