ABSTRACT
Objective To evaluate the extent and anatomic distribution of air trapping in lung in young asymptomatic female subjects to achieve early diagnosis of small airway diseases.Methods Fifty young females with normal pulmonary function were included retrospectively in this study.All subjects underwent both inspiratory and expiratory CT scans,the percentage of the area of air trapping(AT)and the percentage of the area of emphysema(Emph)were quantitatively analyzed.Comparison between bilateral lungs was analyzed using independent-samples t test;Comparisons among lobes were done using one-way ANOVA or Kruskal-Wallis rank sum test;Pairwise comparisons between lobes were conducted using LSD test or paired comparison;The effects of each lobe on AT were analyzed using Spearman's rank correlation coefficient,simple linear regression and multiple stepwise regression.Results There was a certain degree of air trapping in lung and a small amount of emphysema in young asymptomatic females.Air trapping was mainly located in the right middle lobe (RML)and bilateral upper lobes.The ratio of air trapping to volume was the highest in RML and the change of air trapping in the bilateral upper lobes had the greatest influence on the air trapping degree of the whole lung.Conclusion There is a certain degree of air trapping in lung in young asymptomatic females.The occurrence and development of air trapping in RML may be a sensitive biomarker for the early detection of pathophysiological changes in small airway diseases using imaging procedures.