1. Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
2. Department of Medical Biometry, Heidelberg University Hospital, Heidelberg, Germany
3. Department of Neurology, Heidelberg University Hospital, Heidelberg, Germany
4. Department of Neurology and Department of Radiology, Boston Medical Center, Boston, MA, USA
5. Department of Neuroradiology, RWTH Aachen, Aachen, Germany