1. Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
2. Division of Pediatric Neurosurgery, BC Children’s Hospital, Vancouver, British Columbia, Canada
3. Section of Neurosurgery, University of Manitoba, Manitoba, Canada
4. Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada; and
5. Department of Radiology, BC Children’s Hospital, Vancouver, British Columbia, Canada