[1] Capital Med Univ, Dept Echocardiog, Ctr Heart, Beijing Chao Yang Hosp, Beijing 100020, Peoples R China
[2] Capital Med Univ, Dept Resp Med, Beijing Chao Yang Hosp, Beijing 100020, Peoples R China
[3] Capital Med Univ, Beijing Key Lab Resp & Pulm Circulat, Beijing Inst Resp Med, Beijing 100020, Peoples R China
[4] Capital Med Univ, Dept Radiol, Beijing Chao Yang Hosp, Beijing 100020, Peoples R China