1. Departments of Neurology; Alfried Krupp Krankenhaus Essen and Ruhr University Bochum; Bochum Germany
2. University Hospital Münster; Münster Germany
3. Department of Radiology and Neuroradiology; Alfried Krupp Krankenhaus Essen; Essen Germany
4. University Hospital Knappschaftskrankenhaus Bochum and Klinikum Dortmund; Dortmund Germany
5. University Hospital St Josef-Hospital Bochum; Bochum Germany
6. Institute of Epidemiology and Social Medicine; University of Münster; Münster Germany