1. Division of Thoracic Imaging, Department of Medical Imaging, Ottawa Hospital Research Institute, University of Ottawa, 501 Smyth Road, Ottawa K1H 8M2, Canada
2. Division of Radiology, Department of Medicine, Rabigh Medical College, King Abdulaziz University, Jeddah, Saudi Arabia
3. Division of Respirology, Department of Internal Medicine, Ottawa Hospital Research Institute, University of Ottawa, 501 Smyth Road, Ottawa K1H 8M2, Canada
4. Department of Pulmonary and Critical Care Medicine, Stanford University, School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA
5. Department of Pathology and Laboratory Medicine, Ottawa Hospital Research Institute, University of Ottawa, 501 Smyth Road, Ottawa K1H 8M2, Canada