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

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 950 HU (%) 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 (FEV1), the ratio of FEV1 to forced vital capacity (FEV1/FVC), the diffusing capacity for carbon monoxide (DLco) 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 (DLco) (r = -0.35 to -0.61, p < 0.05) and weak positive correlations with TLC (r = 0.34 to 0.44, p < 0.05). Group analysis indicated that LAV-950 HU (%) 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 (p < 0.05).

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