关键词: 肺纤维化合并肺气肿综合征, 肺气肿, 定量CT, 肺功能

Abstract: The study explored the correlation between quantitative CT and lung function in combined pulmonary fibrosis and emphysema (CPFE), and provided a basis for the diagnosis, evaluation, and treatment of CPFE. The study retrospectively 58analyzed 88 CPFE patients who underwent chest high-resolution CT (HRCT) and pulmonary function (PFT) examinations and 96 emphysema patients admitted during the same period. Use 3D Slicer software on CT images based on the threshold segmentation method to obtain quantitative CT indicators, including total lung volume (TLV), normal lung area percentage (NL%), low-density attenuation value (LAA%-950) and high-density attenuation value (HAA%-700). Pearson correlation was used to analyze the correlation between quantitative CT indicators and lung function, and receiver operating characteristic (ROC) curve was used to analyze the diagnostic performance of lung function indicators and quantitative CT indicators in the CPFE group and emphysema group. The calculation results showed that the CPFE group was more likely to occur in smoking men than the emphysema group, and the differences between the two groups in the proportion of men, smoking proportion and smoking pack-years were statistically significant (P<0.05). Except for the vital capacity as a percentage of predicted value (VC%pred) and forced vital capacity as a percentage of predicted value (FVC%pred), there were no statistically significant differences between the CPFE group and the emphysema group. The differences in other lung function indicators were statistically significant (P values are all ＜0.05). There were statistically significant differences in high-density attenuation value (HAA%), low-density attenuation value (LAA%), and total lung volume (TLV) between the two groups (P values are all ＜0.05). TLV, HAA%, LAA% all have the highest correlation with the ratio of forced expiratory volume in first second to forced vital capacity (FEV1/FVC) [r values are －0.67, 0.36, 0.43 respectively, P values are all <0.05)], The normal lung area percentage (NL%) has the highest correlation with the carbon monoxide dispersion volume as a percentage of the predicted value (DLCO%pred) (r=0.53, P＜0.05). ROC curve analysis results show that FEV1/FVC and HAA% are independent predictive factors for distinguishing CPFE from emphysema, with the areas under the curve (AUC) being 0.87 (95%CI: 0.82-0.92) and 0.83 (95%CI: 0.77-0.89) respectively. It can be known from this that quantitative CT indicators can be used for the diagnosis of CPFE and can assess the damage of lung function to a certain extent.

Key words: pulmonary fibrosis combined with pulmonary emphysema syndrome, pulmonary emphysema, quantitative CT, pulmonary function