Computed Tomography Findings of Bronchiectasis in Different Respiratory Phases Correlate with Pulmonary Function Test Data in Adults

Objective To investigate bronchiectasis variations in different computed tomography (CT) respiratory phases, and their correlation with pulmonary function test (PFT) data, in adults. Methods Retrospective data analysis from 63 patients with bronchiectasis according to CT criteria selected from the institution database and for whom PFT data were also available. Bronchiectasis diameter was measured on inspiratory and expiratory phases. Its area and matched airway–vessel ratios in both phases were also calculated. Finally, PFT results were compared with radiological measurements. Results Bronchiectatic airways were larger on inspiration than on expiration (mean cross-sectional area, 69.44 vs. 40.84 mm 2 ; p < 0.05) as were airway–vessel ratios (2.1 vs. 1.4; p < 0.05). Cystic bronchiectasis cases showed the least variation in cross-sectional area (48%). Mean predicted values of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were 81.5 and 77.2%, respectively, in the group in which bronchiectasis could not be identified on expiratory images, and 58.3 and 56.0%, respectively, in the other group ( p < 0.05). Variation in bronchiectasis area was associated with poorer lung function ( r = 0.32). Conclusion Bronchiectasis detection, diameter, and area varied significantly according to CT respiratory phase, with non-reducible bronchiectasis showing greater lung function impairment.