Chest CT imaging toward personalized management of chronic obstructive pulmonary disease, asthma, and bronchiectasis:...

Chronic airway diseases, including chronic obstructive pulmonary disease (COPD), asthma, and bronchiectasis, impose substantial morbidity and mortality worldwide. Precise phenotyping of their complex pathophysiological manifestations is essential for effective management. Chest computed tomography (CT) allows qualitative and quantitative assessments of emphysema, airway structure, mucus plugs, vascular abnormalities, bronchiectasis, and comorbid interstitial lung abnormality, making it central to charactering these conditions. From perspectives of pulmonologists who use chest CT with guidance from radiologists, this review describes the advances in CT image analysis and their implications for patients with chronic airway disease. On inspiratory CT, low-attenuation regions reflect emphysema and are associated with clinical outcomes in smokers. Airway lumen, wall size, branch count, and fractal dimension correlate with disease severity and lung function impairment in COPD and asthma. Airway mucus plugs reflect inflammatory patterns and are associated with reduced lung function and exacerbations; however, mucus plugs are increasingly recognized as a treatable trait in the era of biologics treatment. Pulmonary vascular abnormalities are quantified using pulmonary artery-to-aorta diameter ratio and small vessel volume proportions. Along with chronic symptoms, bronchiectasis is diagnosed radiologically by an increased broncho-arterial ratio, absent bronchial tapering, and peripheral airway visibility. Although limited spatial resolution precludes direct evaluation of small airway disease, air-trapping on expiratory CT or registered Inspiratory-expiratory CT allows indirect estimation of small airway disease. Despite these advances, many research findings remain unapplied to routine clinical image analysis. Radiation exposure is an inherent limitation. Nonetheless, chest CT provides greater diagnostic information than chest radiography and is more accessible than magnetic resonance imaging and nuclear imaging. Further studies are needed to maximize the potential of chest CT for early detection, risk stratification, and treatment monitoring in airway disease management.