1. Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Düsseldorf, D-40225 Düsseldorf, Germany
2. Division of Informatics and Statistics, Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Düsseldorf, D-40225 Düsseldorf, Germany
3. Institute for Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, D-40225 Düsseldorf, Germany