1. University Institute of Diagnostic and Interventional Neuroradiology, University of Bern, Inselspital, Bern, Switzerland
2. Clinical Trials Unit Bern, Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
3. Department of Neurosurgery, University of Bern, Inselspital, Bern, Switzerland
4. Department of Neurosurgery, Medical Center–University of Freiburg, Freiburg, Germany