Hisako Kushima1, Hiroshi Ishii2, Fumito Okada3, Jun-ichi Kadota1. 1. Department of Respiratory Medicine, Oita University Hospital, Yufu, Japan. 2. Department of Respiratory Medicine, Fukuoka University Hospital, Fukuoka, Japan. 3. Department of Radiology, Oita University Hospital, Yufu, Japan.