Abstract / Summary
BackgroundChronic obstructive pulmonary disease (COPD) is diagnosed primarily by post-bronchodilator spirometry, but quantitative CT can characterize emphysema and visible-airway structural abnormalities that are not fully captured by airflow measurements alone. Because CT-derived emphysema and airway features have been extensively studied, this single-center study aimed to develop and describe quantitative CT-based classification models and to explore bronchial-tree morphology as a hypothesis-generating imaging phenotype, rather than to establish a clinically validated diagnostic replacement for pulmonary function testing.MethodsWe enrolled 229 participants (138 with COPD and 91 control participants) at Fudan University Zhongshan Hospital. HRCT was used to quantify visible-airway dimensions at a prespecified eighth-generation airway, emphysema extent quantified as low attenuation area percentage (LAA%), and bronchial-tree morphology. Clinical variables including smoking history, modified Medical Research Council (mMRC) dyspnea score, and pulmonary function tests were recorded. Multivariable logistic regression was used to develop single-center models for COPD classification and for classification of severe airflow obstruction (FEV1%pred < 50%, corresponding to GOLD spirometric grades 3–4). Model performance is reported as apparent performance because internal and external validation were not performed.ResultsCompared with control participants, COPD participants had smaller airway lumen area, higher wall-to-diameter ratio (T/D), higher wall area percentage (WA%), and higher LAA%. Mean wall thickness did not differ significantly, indicating that the group difference mainly reflected lumen narrowing rather than wall thickening. Emphysema extent was associated with lower FEV1/FVC and FEV1%pred. Sparse-type bronchial morphology was associated with COPD in multivariable analysis (OR 28.6, 95% CI 6.7–149.8), but the wide confidence interval and the need for reproducible operational validation require cautious interpretation. The combined clinical-CT development models achieved apparent AUCs of 0.906 for COPD classification and 0.859 for classification of severe airflow obstruction.ConclusionQuantitative HRCT emphysema and visible-airway measurements were associated with COPD status and spirometric airflow obstruction. The models should be regarded as single-center development models, and the bronchial-tree morphology finding should be interpreted as hypothesis-generating until reproducibility, calibration, incremental value, and external validation are demonstrated.