Quantitative study on the degree of small airway disease and emphysema injury in pulmonary lobes of patients with smoking combined with chronic obstructive pulmonary disease based on biphasic CT / 中华放射学杂志

ABSTRACT

Objective:To explore the value of biphasic quantitative CT on small airway disease and emphysema injury in patients with smoking combined with chronic obstructive pulmonary disease (COPD).Methods:A total of 186 male physical examination subjects who underwent biphasic CT and pulmonary function (PFT) examinations in the Affiliated Hospital of Yan′an University from July 2018 to September 2020 were enrolled in this retrospective study. These subjects were divided into 121 smokers with COPD (COPD group), aged 34 to 84 (64±8) years old and 65 smokers without COPD (non-COPD group) aged 34 to 72 (61±5) years old. According to the guidelines of the COPD global initiative, patients in COPD group were divided into Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) Ⅰ-Ⅳ grades. The original DICOM data of CT were imported into the "Digital Lung" test and analysis platform. Quantitative parameters of functional small airway disease percentage (fSAD%) and emphysema area percentage (Emph%) of each lobe were calculated. The differences of CT quantitative parameters among non-COPD group and each grade in COPD group were analyzed by One-Way ANOVA or Kruskal-Wallis H test. The correlation between the smoking index and CT quantitative parameters was analyzed by Spearman correlation analysis. Results:There were significant differences in fSAD% and Emph% of each lobe among non-COPD group and COPD group GOLD Ⅰ-Ⅳ ( P<0.001). Except that the Emph% in right middle lobe of GOLD grade Ⅰ was higher than that of GOLD grade Ⅱ in COPD group, the fSAD% and Emph% in other lobes increased gradually with the increase of GOLD grade in COPD group. The fSAD% and Emph% were larger in the right middle lobe and both upper lobes of COPD group GOLD Ⅰ-Ⅳ. The comparison among each lobe showed that the differences were statistically significant ( P<0.01), except for the fSAD% and Emph% of GOLD Ⅳ ( P=0.395, 0.840). The smoking index was positively correlated with fSAD% and Emph% in each lung lobe. Among them, smoking index was highly correlated with fSAD% in the lower right lobe and Emph% in the lower left lobe ( r=0.474, 0.619, P<0.001). Conclusion:The biphasic quantitative CT can early and sensitively reflect the degree of small airway disease and emphysema injury in smoking combined with COPD, which is of great significance for the early diagnosis and evolution of COPD.