1. Department of Neurosurgery, Kantonsspital Aarau, 5001 Aarau, Switzerland
2. Division of Neuroradiology, Department of Radiology, Kantonsspital Aarau, 5001 Aarau, Switzerland
3. Department of Neurosurgery, Universitätsmedizin Aachen, RWTH Aachen University, 52074 Aachen, Germany
4. Division of Neuroradiology, Kantonsspital Aarau, University of Bern, 3008 Bern, Switzerland
5. Faculty of Medicine, University of Bern, 3008 Bern, Switzerland