1. Department of Neurology, University Hospital Giessen and Marburg, Giessen, Germany.
2. Department of Radiology and Neuroradiology, University Hospital Essen, Essen, Germany.
3. Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany.
4. Department of Neuroradiology, University Hospital Giessen and Marburg, Giessen, Germany.