1. Department of Internal Medicine, Konkuk University Chungju Hospital, Chungju, Korea.
2. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Chungju Hospital, Chungju, Korea.
3. Department of Thoracic and Cardiovascular Surgery, Konkuk University Chungju Hospital, Chungju, Korea.
4. Division of Allergy and Pulmonology, Department of Internal Medicine, Konkuk University Chungju Hospital, Chungju, Korea.