1. Department of Neurosurgery, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79106, Germany
2. Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79106, Germany
3. Institute of Diagnostic and Interventional Neuroradiology, RKH Kliniken Ludwigsburg-Bietigheim, Ludwigsburg 71640, Germany