1. Department of Radiology; McMaster University; Hamilton ON Canada
2. Department of Clinical Epidemiology and Public Health; University of Ottawa; Ottawa ON Canada
3. The Ottawa Hospital Research Institute; Clinical Epidemiology Program; Ottawa ON Canada
4. Department of Medicine; McMaster University; Hamilton ON Canada
5. Department of Medicine; Western University; London ON Canada
6. Department of Medicine; New York Institute of Technology School of Osteopathic Medicine; Glen Head NY USA
7. Department of Radiology; St Joseph's Healthcare; McMaster University; Hamilton ON Canada