1. Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94107, USA
2. Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Freiburg im Breisgau
3. Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany