1. Department of Neurology, Alfried Krupp Krankenhaus Essen, Alfried-Krupp-Str. 21, 45131 Essen, Germany
2. Department of Neurology, Klinikum Dortmund, Germany
3. Department of Neurology, University Hospital of Duisburg-Essen, Germany
4. Institute of Epidemiology and Social Medicine, University of Münster, Germany
5. Department of Radiology and Neuroradiology, Alfried Krupp Krankenhaus Essen, Germany
6. Department of Neurology, Alfried Krupp Krankenhaus Essen, Germany
7. Department of Radiology and Neuroradiology, Klinikum Duisburg, Germany
8. Department of Neurology, Klinikum Bergmannsheil Bochum, Germany
9. Department of Neurology, St Josef-Hospital Bochum, Germany
10. Neuroradiology, Klinikum Vest Recklinghausen and Knappschaftskrankenhaus Bochum, Germany
11. Department of Neurology, St Josef Krankenhaus Moers, Germany
12. Department of Neurology, Knappschaftskrankenhaus Bochum, Germany