Tracheal morphology and collapse in COPD: correlation with CT indices and pulmonary function test

To assess the tracheal morphologic changes using CT in COPD (chronic obstructive lung disease) patients and to assess correlation between them and PFT (pulmonary function test) and CT parameters.

Ninety-two healthy individuals and 115 patients with COPD who underwent volumetric inspiration/expiration CT scanning were included. The Lsag, Lcor, and the tLA were measured. The TI was defined as the ratio of Lcor/Lsag. The tracheal morphologic changes (tLA, TI, and collapsibility) were compared in healthy individuals and COPD. In COPD patients, correlation of the tracheal morphologic change with PFT and CT parameters was assessed.

The TIs in the COPD patients were significantly lower than those in the control group (0.80±0.15 vs. 0.88±0.11, Mean±SD) (p<0.01). In COPD patients, TI correlated with FEV1 (r=0.29, p=<0.01), FEV1/FVC (r=0.26, p<0.01), and the GOLD stage (r=-0.26, p<0.01). TI showed significant correlation with EI on both inspiration and expiration CT (r=-0.19, p=0.04 and r=-0.23, p=0.02), MLD on expiration CT (r=0.27, p<0.01), CT-ATI (r=0.34, p<0.01), and with LV on expiration CT (r=-0.25, p<0.01).

Among the tracheal morphologic changes, the most significant change in COPD patients compared with that in the control group, was the TI. In COPD patients, the tracheal morphologic change showed clinically significant correlation with severity of emphysema and CT indices.