Thin-section CT finding in 250 volunteers: assessment of the relationship of CT findings with smoking history and pulmonary function test results.

PURPOSE

To evaluate the frequency and morphologic characteristics of air trapping in volunteers with various smoking habits.

MATERIALS AND METHODS

Two hundred fifty volunteers (133 women, 117 men; mean age, 39 years), including 144 smokers, 47 ex-smokers, and 59 nonsmokers, prospectively underwent inspiratory and expiratory high-spatial-resolution computed tomography (CT) and pulmonary function tests (PFTs). The frequency and characteristics of air trapping were evaluated according to the population's smoking habits and PFT results.

RESULTS

The overall frequency of air trapping was 62% (155 of 250 subjects). Lobular air trapping was depicted in 117 (47%) of 250 subjects, without significant differences among smokers (n = 91), ex-smokers (n = 33), and nonsmokers (n = 31) (P =.118). Segmental and lobar air trapping (38 [15%] of 250) were more frequent among smokers (24 [26%] of 91) and ex-smokers (nine [27%] of 33) (P <.001). No relationship was found between air trapping and functional indexes of small-airway disease when the CT pattern of air trapping was considered. The strongest relationship between CT abnormalities and functional alterations at the small-airways level was between inspiratory CT features of bronchiolitis: ground-glass opacity, ill-defined micronodules, bronchiolectasis, and air flow at low lung volumes.

CONCLUSION

Whereas a significant relationship was observed between segmental and lobar air trapping and cigarette consumption, lobular air trapping was not found to reflect functional impairment at the small-airways level.