1. From the Departments of Neuroradiology (J.B.F., M.M., P.W., J.B., P.S., M.H., S.H., M.K., K.S.) and Neurology (P.D.S., E.J., J.O., W.H.), University of Heidelberg Medical School, Heidelberg, Germany, and Department of Neuroradiology, University of Kiel Medical School, Kiel, Germany (O.J.).