1. From the Departments of Neuroradiology (P.S., J.B.F., S.H., K.S.) and Neurology (P.D.S., S.K.), University of Heidelberg Medical School, Germany; NINDS (P.D.S.), NIH, Bethesda, Md; Siemens Medical Solutions (E.K.), Forchheim, Germany; and Department of Neuroradiology (K.K., M.K.), University of Göttingen Medical School, Germany.