1. From the Institute of Clinical Radiology (M.B., T.N., W.H., M.W., A.K., P.B.S.), Westfaelische Wilhelms-University of Muenster and Albert-Schweitzer-Campus 1, Germany
2. Department of Pediatrics, University Hospital of Muenster (R.S.), Westfaelische Wilhelms-University of Muenster and Albert-Schweitzer-Campus 1, Germany
3. Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Germany (U.H.).