1. Department of Radiology, School of Medicine and Graduate School of Medicine, Juntendo University, 2-1-1 Hongo Bunkyo-ku, Tokyo, Japan
2. Department of Ultrasound, Shaanxi Provincial People's Hospital, Xi'an, China
3. Division of Respiratory Medicine, School of Medicine and Graduate School of Medicine, Juntendo University, 2-1-1 Hongo Bunkyo-ku, Tokyo, Japan