1. Department of Neuroradiology, Katharinenhospital, Klinikum Stuttgart, Stuttgart, Germany
2. Universitätsklinikum Knappschaftskrankenhaus Bochum, Bochum, Germany
3. Department of Neurology, Bürgerhospital, Klinikum Stuttgart, Stuttgart, Germany
4. Medical Faculty, University of Duisburg-Essen, Essen, Germany