1. Division of Respiratory and Critical Care, Department of Internal Medicine,
2. College of Medicine, Seoul National University, Seoul, Korea;
3. Department of Radiology, and
4. Medical Research Collaborating Center, Seoul Metropolitan Government–Seoul National University Boramae Medical Center, Seoul, Korea;
5. Department of Internal Medicine,
6. Department of Internal Medicine, College of Medicine,
7. Department of Medical Engineering, and
8. Department of Biomedical Engineering, Gachon University, Incheon, Korea;
9. Department of Radiology, Gil Medical Center, College of Medicine, and
10. School of Medicine, Konyang University, Daejeon, Korea; and
11. Department of Radiology, Konyang University Hospital, Daejeon, Korea