1. Department of Diagnostic and Interventional Neuroradiology, University-Hospital of Tuebingen, 72076 Tuebingen, Germany
2. Department of Diagnostic and Interventional Radiology, University-Hospital of Tuebingen, 72076 Tuebingen, Germany
3. Department of Diagnostic Radiology, IWK Health Care Centre, 5850 University Avenue, Halifax, NS B3K 6R8, Canada