1. Department of NeurosurgeryCantonal Hospital St. Gallen 9007 St. Gallen Switzerland
2. Department of Neurology and Brain Tumor CenterCantonal Hospital Aarau 5001 Aarau Switzerland
3. Department of NeuroradiologyCantonal Hospital Aarau 5001 Aarau Switzerland
4. University of Bern Bern Switzerland