The Evaluation of the Inner Diameter of the Airway in Asthma Recovery by Using HRCT: A Retrospective Observational Cohort Study

Background: Although airway size changes occur in patients with chronic asthma, HRCT has not yet been used to assess changes in the inner diameter of the airways. Objective: This study aimed to evaluate the airway diameter in asthma recovery by using HRCT. Methods: Thirty patients with asthma were recruited and underwent HRCT examination in acute exacerbation and stable phase, respectively. The inner diameter of the airway (Din) was measured from the bilateral main bronchi to all 18 segmental bronchi during acute exacerbation and the stable phase. Results: The inner diameter of the airway reduced significantly in the acute exacerbation period compared to the stable period (P < 0.05). The mean Din reduction (%) in segmental bronchi was 12% and that in lobar bronchi was 6%. Among the 30 patients, the dorsal segmental bronchi of both lower lobes showed the highest incidence of stenosis during acute exacerbation compared to the stable phase (right: 18 cases; left: 16 cases), while the lingular bronchus exhibited the highest stenosis incidence among lobar bronchi (18 cases). Although the number of stenotic segmental and lobar bronchi demonstrated a positive correlation with disease severity across mild, moderate, and severe groups, no statistically significant differences were observed in intergroup comparisons (P>0.05). Conclusion: CT images of bronchial stenosis showed obvious dilation after appropriate medication, and the inner diameter of the airway can be used as a practical and convenient index to evaluate the recovery of asthma.