Relationships between pulmonary function test parameters and quantitative computed tomography measurements of emphysema in subjects with chronic obstructive pulmonary disease.

Objective: CT is able to precisely define the pathological process in COPD. There are a number of previous articles discussing the distribution of emphysema and its connection with pulmonary function tests. However, the results obtained by the researchers are not identical.

Purpose: To assess relationships between emphysema and pulmonary function test parameters in COPD patients.

Materials And Methods: Fifty-nine patients diagnosed to have COPD underwent chest CT examinations and pulmonary function tests.For the quantitative assessment, percentages of low attenuation volume LAV (%) of a both lungs, the right lung, the left lung, and each lobe were obtained. Quantitative CT measurements were compared with forced expiratory volume in 1 s (FEV), the ratio of FEV to forced vital capacity (FEV/FVC), the diffusing capacity for carbon monoxide (Lco) and total lung capacity (TLC).

Results: Except for the right middle lobe and the right upper lobe, respectively, all the quantitative CT measurements showed weak to moderate negative correlations with diffusing capacity (Lco) ( = -0.35 to -0.61, < 0.05) and weak positive correlations with TLC ( = 0.34 to 0.44, < 0.05). Group analysis indicated that LAV (%) values of both lungs, right lung, left lung, and each lobe, except for right middle lobe, were increased in patients with GOLD stages 3 and 4 of COPD compared to GOLD stages 1 and 2 ( < 0.05).

Conclusion: CT measurements of emphysema are significantly related to pulmonary function tests results, particularly Lco.