1. Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
2. Department of Diagnostic Imaging, Foothills Medical Center, University of Calgary, Calgary, Alberta, Canada
3. Division of Neuroradiology, Clinic of Radiology and Nuclear Medicine, University Hospital Basel, University of Basel, Basel, Switzerland
4. Department of Clinical Neurosciences, Foothills Medical Center, University of Calgary, Calgary, Alberta, Canada