1. Division of Neuroradiology, Department of Diagnostic Radiology, Dalhousie University, Halifax, Nova Scotia, Canada
2. Division of Neurosurgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
3. Division of Vascular Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
4. Division of Cardiac Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada