[1] Kokura Mem Hosp, Dept Resp Med, 3-2-1 Asano,Kokurakita Ku, Kitakyushu, Fukuoka 8028555, Japan
[2] Kokura Mem Hosp, Dept Otorhinolaryngol, Kitakyushu, Fukuoka, Japan
[3] Kokura Mem Hosp, Dept Diagnost Radiol, Kitakyushu, Fukuoka, Japan
[4] Univ Occupat & Environm Hlth, Dept Resp Med, Kitakyushu, Fukuoka, Japan