1. Department of Otolaryngology–Head and Neck Surgery, The Hospital for Sick Children University of Toronto Toronto Ontario Canada
2. Department of Otolaryngology–Head and Neck Surgery, National Children's Hospital San José Costa Rica
3. Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging University of Toronto Toronto Ontario Canada
4. Red Cross War Memorial Children's Hospital Cape Town South Africa
5. Division of Otorhinolaryngology, Head and Neck Surgery University of Cape Town Cape Town South Africa
6. Department of Radiology, Division of pediatric radiology, Children's Hospital of Eastern Ontario Ottawa Ontario Canada