Study Of Postoperative Pulmonary Function Prediction Values By Quantitative CT In Evaluating Postoperative Pulmonary Complication After Lobectomy

Objective:Quantitative computed tomography（QCT）was used to measure functional lung volume（FLV）and predict postoperative pulmonary function,and to explore the value of quantitative computed tomography postoperative pulmonary function predictive value in evaluating pulmonary complication（PPC）after lobectomy.Methods:151 patients who underwent lobectomy in the Department of Thoracic surgery of the affiliated Hospital of Zunyi Medical University from March 2019 to October 2020and had thin-layer chest CT images and pulmonary function test（PFT）results before the operation were consecutively collected.According to the presence or absence of postoperative pulmonary complication,they were divided into PPC group and non-PPC group.Collecting the clinical data（age,gender,smoking index,etc）and preoperative PFT indicators,including total lung capacity（TLC）,forced expiratory volume in the first second（FEV₁）,the percentage of forced expiratory volume in the first second in predicted value（FEV₁%pred）,forced vital capacity（FVC）,diffusion capacity for carbon monoxide（DLCO）,etc.QCT was used to determine the preoperative total functional lung volume（TFLV）,the functional lung volume of the lung lobe to be resected（RFLV）and the residual lung functional lung volume.The values of postoperative pulmonary function indexes were calculated by QCT method and anatomical segmentation method.The clinical data,preoperative PFT indexes,preoperative QCT functional lung volume（FLV）indexes,and postoperative pulmonary function prediction indexes of QCT method and anatomical segmentation method were analyzed by single factor analysis.The meaningful variables and indexes were included as independent variables,and the postoperative pulmonary complication was taken as dependent variable.Binary logistics regression analysis was performed on the evaluation of postoperative pulmonary complication by the postoperative pulmonary function prediction indexes of QCT method and anatomical segmentation method,respectively.On this basis,the receiver operating characteristic（ROC）curve was drawn,and the area under the ROC curve（AUC）of the postoperative pulmonary function prediction indexes of QCT method and anatomical segmentation method to evaluate the postoperative pulmonary complication was compared.The prediction efficiency of the two methods to evaluate the postoperative pulmonary complication was compared.The difference was statistically significant when P<0.05.Results:（1）There were 42 cases in the PPC group and 109 cases in the no-PPC group.（2）Clinical data:the age of PPC group was higher than that of non-PPC group,and the difference was statistically significant（P<0.05）.There was statistically significant difference in gender ratio between PPC group and non-PPC group（P<0.05）,and males were more than females in PPC group.The smoking index in the PPC group was higher than that in the non-PPC group,and the difference was statistically significant（P<0.05）.There was no significant difference in the distribution of complication,treatment group and disease types between PPC group and non-PPC group（P>0.05）.3)Preoperative PFT indexes:TLC of PPC group was higher than that of non-PPC group,the difference was statistically significant（P<0.05）.Preoperative QCT functional lung volume indexes:the residual lung functional lung volume of PPC group was lower than that of non-PPC group,the difference was statistically significant（P<0.05）.（4）The preoperative QCT whole lung functional lung volume was correlated with FVC,TLC,FEV₁,DLCO and RV（P<0.05）,and the correlation with FVC,TLC and FEV₁was better,and the correlation coefficients（r）were 0.55,0.47 and 0.46,respectively.;The residual functional lung volume of the PPC group was smaller than that of the non-PPC group,the difference was statistically significant（P<0.05）.（5）The predicted values of postoperative pulmonary function indexes:the predicted values of FEV₁and FEV₁%pred of postoperative pulmonary function indexes by QCT method in the PPC group were lower than those in non-PPC group,and the difference was statistically significant（P<0.05）.The predicted FEV₁and FEV₁%pred of postoperative pulmonary function indexes by anatomical segmentation method of PPC group were lower than those of non-PPC group,and the difference was statistically significant（P<0.05）.（6）Logistics regression analysis:Considering the influence of gender,age,smoking index and preoperative pulmonary function index on postoperative pulmonary complication,the predictive value of FEV1 and FEV1%pred of QCT method and the predictive value of FEV1%pred of anatomical segment method were the predictors of postoperative pulmonary complication（P<0.05）.（7）ROC curve analysis:The AUC of QCT method was larger than that of anatomical segmentation method,and the difference was statistically significant（P<0.05）.The efficiency of QCT method in predicting postoperative pulmonary complication was better than that of anatomical segmentation method.Conclusion:（1）Age,gender,smoking index and preoperative pulmonary function index（TLC）are the influencing factors of postoperative pulmonary complication.（2）QCT residual lung function lung volume and postoperative pulmonary function predictive value can be used as indicators for evaluating postoperative pulmonary complication.