1. Department of Intensive Care MedicineInselspital, Bern University Hospital, and University of Bern, Switzerland
2. Department of NeurosurgeryKantonsspital Aarau, Switzerland
3. Department of NeurosurgeryUniversity Hospital Cologne, Germany
4. Department of NeurosurgeryRudolfstiftung, Vienna, Austria
5. Department of Biomedical ResearchCerebrovascular Research Group, Medical University Vienna, Austria
6. Division of NeuroradiologyDepartment of Radiology, Kantonsspital Aarau, Switzerland