1. Department of Radiology, McMaster University, St Joseph's Healthcare, Hamilton, Ontario, Canada
2. Department of Radiology, McMaster University, Hamilton General Hospital, Hamilton, Ontario, Canada
3. Mallinckrodt Institute of Radiology, St Louis, Missouri, USA
4. Montefiore Medical Center, Bronx, New York, USA
5. Humber River Hospital, Toronto, Ontario, Canada
6. NYU Winthrop-University Hospital, Mineola, New York, USA