1. From the Department of Neuroradiology (F.S., M.A.M., F.H., M.B.), Heidelberg University Hospital, Germany
2. Department of Neuroradiology (J.F., F.F., C.B.), University Hospital Hamburg-Eppendorf, Germany
3. Department of Neurology (P.A.R.), Heidelberg University Hospital, Germany
4. Department of Neurology (G.T.), University Hospital Hamburg-Eppendorf, Germany
5. Department of Neurology, Klinikum Frankfurt Höchst, Germany (T.S.)
6. Department of Neurology, Klinikum Lüneburg, Germany (C.K.).