[1] Ilsan Hosp, Dept Internal Med, Div Pulmonol, Natl Hlth Insurance Serv, Goyang, South Korea
[2] Yonsei Univ, Grad Sch Med, Seoul, South Korea
[3] Yonsei Univ, Severance Hosp, Dept Internal Med, Div Pulm & Crit Care Med,Coll Med, 50-1 Yonsei-ro, Seoul 03722, South Korea
[4] Yonsei Univ, Severance Hosp, Res Inst Radiol Sci, Dept Radiol,Coll Med, Seoul, South Korea
[5] Yonsei Univ, Coll Med, Inst Immunol & Immunol Dis, Seoul, South Korea