Quantitative Assessment of Airway Pathology in Subjects With COPD Using Low-Dose High-Resolution Computed Tomography

The purpose of this study was to correlate airway parameters of COPD determined by low-dose high-resolution computed tomography (HRCT) with pulmonary function testing (PFT) results.

PFT data were collected for subjects with COPD and healthy controls. All subjects received inspiratory and expiratory phase low-dose HRCT. Bronchi in the apical segment of the right upper lobe (RB1), posterior segment of the right lower lobe (RB6), and lower lingual segment of the left upper lobe (LB5) were the target bronchi. Software automatically calculated airway wall area, inner area, and airway wall area percentage (percentage wall area for bronchial external area).

A total of 75 COPD and 20 control subjects were included. The subjects with COPD were classified according to COPD stage, with 20 grade I, II, and III subjects, respectively, and 15 grade IV subjects. In COPD grade II, residual volume/total lung capacity was negatively correlated with airway wall area in LB5 (r = -0.51). In COPD grade III, FVC was negatively correlated with airway wall area percentage in LB5 (r = -0.49) but positively correlated with airway wall area in RB6 (r = 0.52); percent-of-predicted FEV₁ was negatively correlated with airway wall area percentage in RB1 (r = -0.49); residual volume was negatively correlated with airway wall area (r = -0.47), and total lung capacity was negatively correlated with airway wall area in RB1 (r = -0.52) (all, P < .001).

The results of this study suggest that airway parameters in different COPD grades have no uniform tendency of correlation with PFT, but some HRCT parameters are correlated to some PFT parameters.