1. Clinical Medical College of Chengdu Medical College, Chengdu, Sichuan, China
2. Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan, China
3. Key Laboratory of Geriatric Respiratory Diseases of Sichuan Higher Education Institutes, Chengdu, Sichuan, China
4. Radiology department, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan, China
5. Department of Pulmonary and Critical Care Medicine, Chengdu Shuangnan Hospital, Chengdu, Sichuan, China
6. Guanghan Shilin Clinic of Integrated Traditional Chinese and Western Medicine, Deyang, Sichuan, China.