[1] Ibaraki Prefectural Cent Hosp & Canc Ctr, Resp Ctr, 6528 Koibuchi, Kasama, Ibaraki 3091793, Japan
[2] Hitachi Gen Hosp, Div Resp Med, Hitachi, Ibaraki, Japan
[3] Hitachi Gen Hosp, Div Thorac Surg, Hitachi, Ibaraki, Japan
[4] Ibarakihigashi Hosp, Div Resp Med, Tokai, Ibaraki, Japan
[5] Univ Tsukuba, Hitachinaka Gen Hosp, Div Resp Med, Hitachinaka Med Ctr, Hitachinaka, Ibaraki, Japan
[6] Mito Med Ctr, Div Resp Med, Mito, Ibaraki, Japan
[7] Mito Med Ctr, Div Thorac Surg, Mito, Ibaraki, Japan
[8] Univ Tsukuba, Mito Kyodo Gen Hosp, Div Resp Med, Mito Med Ctr, Mito, Ibaraki, Japan
[9] Univ Tsukuba, Mito Kyodo Gen Hosp, Div Thorac Surg, Mito Med Ctr, Mito, Ibaraki, Japan
[10] Tsuchiura Kyodo Gen Hosp, Div Resp Med, Tsuchiura, Ibaraki, Japan
[11] Tsuchiura Kyodo Gen Hosp, Div Thorac Surg, Tsuchiura, Ibaraki, Japan
[12] Kasumigaura Med Ctr Hosp, Div Resp Med, Tsuchiura, Ibaraki, Japan
[13] Tsukuba Med Ctr Hosp, Div Resp Med, Tsukuba, Ibaraki, Japan
[14] Tsukuba Med Ctr Hosp, Div Thorac Surg, Tsukuba, Ibaraki, Japan
[15] Tsukuba Mem Hosp, Div Resp Med, Tsukuba, Ibaraki, Japan
[16] Univ Tsukuba, Fac Clin Med, Tsukuba, Ibaraki, Japan
[17] Tsukuba Gakuen Hosp, Div Resp Med, Tsukuba, Ibaraki, Japan
[18] Ryugasaki Saiseikai Hosp, Div Resp Med, Ryugasaki, Japan
[19] Ibaraki Seinan Med Ctr Hosp, Div Resp Med, Sakai, Osaka, Japan
[20] Tokyo Med Univ, Ibaraki Med Ctr, Div Resp Med, Ami, Japan
[21] JA Toride Med Ctr Hosp, Div Resp Med, Toride, Japan