1. Department of Neurological Surgery, Heinrich-Heine-Universität, Düsseldorf, Germany
2. Department of Neuroradiology, Heinrich-Heine-Universität, Düsseldorf, Germany
3. Department of Neuroradiology, Ludwig-Maximilians-Universität, Munich, Germany
4. Department of Neurological Surgery, Ludwig-Maximilians-Universität, Munich, Germany