Airway Remodeling in Asthma: Evaluation in 5 Consecutive Bronchial Generations by Using High-Resolution Computed Tomography.

BACKGROUND

Airway remodeling is a characteristic structural change that occurs extensively in the airways of patients with asthma. The change can be evaluated by measuring airway dimensions by using high-resolution computed tomography. This study aimed to explore the variation trends of airway dimensions from the second- to sixth-generation bronchi in subjects with asthma.

METHODS

Sixty subjects with asthma and 40 healthy controls underwent high-resolution computed tomography. The right upper lobe apical segmental bronchus, right lower lobe posterior basal segmental bronchus, left upper lobe apicoposterior segmental bronchus, and the left lower lobe posterior basal segmental bronchus were identified on computed tomography images. The luminal area, wall area, and wall area percentage of each bronchus were measured from the second (lobar) to the sixth generation. The variation trends of these indices (luminal area, wall area, and wall area percentage) were then compared between the subjects with asthma and the healthy controls.

RESULTS

From the proximal to the distal airway, the luminal area and wall area decreased gradually, whereas the wall area percentage increased gradually in all the participants; the difference between the participants with asthma and the healthy controls in the luminal area, wall area, and wall area percentage increased gradually from the second (lobar) to the sixth generation; there was a significant difference between the participants with asthma and the healthy controls in the right lower lobe posterior basal segmental bronchus, left upper lobe apicoposterior segmental bronchus, and left lower lobe posterior basal segmental bronchus wall area percentage (P = .001, .01 and .001, respectively) but not in the right upper lobe apical segmental bronchus wall area percentage (P = .050).

CONCLUSIONS

Airway remodeling in asthma was more prominent in distal airways and at lower lobe bronchi.