1. Departments of Neurosurgery,
2. Neuroradiology, and
3. Department of Cranio-Maxillo-Facial Surgery, University Medical Center, Regensburg, Germany;
4. Institute of Neuroradiology, University of Frankfurt, Frankfurt/Main, Germany;
5. Neurology, Bern University Hospital, Bern, Switzerland;
6. Department of Neurosurgery, Ospedale Cantonale di Lugano, Switzerland; and
7. Institute of Mathematical Statistics and Actuarial Science, University of Bern, Switzerland