1. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
4. Department of Thoracic and Cardiovascular Surgery, Seoul National University College of Medicine, Seoul, Korea.