1. Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
2. Lung Research Institute, Hallym University College of Medicine, Chuncheon, Korea.
3. Department of Internal Medicine, Jeju National University Hospital, Jeju, Korea.
4. Department of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
5. Department of Radiology, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
6. Division of Pulmonary, Allergy and Critical Care Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea.
7. Division of Pulmonary, Allergy and Critical Care Medicine, Hallym University Dongtan Sacred Heart Hospital, Hwaseong, Korea.