1. State Key Laboratory for Pneumoconiosis of National Health Commission, Key Laboratory of Prevention, Treatment and Fundamental Studies for Respiratory Diseases of Shanxi, Department of Respiratory and Critical Care Medicine, First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
2. Department of Ultrasonic Imaging, First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
3. School of Medical Application Technology, Shenyang Medical College, Shenyang, Liaoning 110034, P.R. China
4. Department of Clinical Laboratory, People's Hospital of Lüliang, Lüliang, Shanxi 033000, P.R. China
5. Key Laboratory of Cellular Physiology of The Ministry of Education and Department of Pathology, Shanxi Medical University, Yingze, Taiyuan, Shanxi 030001, P.R. China