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