We recruited COPD patients (stage I-II, n=15; stage III-IV, n= 15), Pre-COPD (n= 20) and healthy never-smokers (healthy human, n=21). Age,gender,BMI, smoking history, spirometry, chest computed tomography (CT), bronchoscopy and EB-OCT were performed. Inner luminal area (Ai) and airway wall area (Aw) of bronchi which inner perimeter was 10mm, 20mm and 30mm were measured using EB-OCT respectively. By analyzing and studying the above situation, we aim to discover the application value of OCT in Pre-COPD
