Value Of Dual-detector Spectral CT Multi-parameter Imaging In Pathological Types And Differentiation Degree Of Lung Cancer

Objective:To explore the diagnostic evaluation of quantitative parameters of dual-layer spectral detector CT（DSCT）for different pathological types of lung cancer,different pathological differentiation degrees of lung adenocarcinoma and their correlation with the size of the lesion.Methods:From August 2021 to November 2022,a total of 88 patients with lung cancer underwent chest dual-phase enhanced scanning with DSCT in our hospital were analyzed.According to the pathological results,they were divided into lung adenocarcinoma group（n=42）,lung squamous cell carcinoma group（n=30）and small cell lung cancer group（n=16）,of which the lung adenocarcinoma group includes moderately-highly differentiated lung adenocarcinoma group（Group I,n=20）and poorly differentiated lung adenocarcinoma group（Group II,n=22）,Further,according to the maximum diameter of the lesion（Dmax）,the moderately differentiated lung adenocarcinoma group and the poorly differentiated lung adenocarcinoma group were divided into group Ia（Dmax<3cm,n=11）,group Ib（Dmax≥3cm,n=9）and group IIa（Dmax<3cm,n=9）,group IIb（Dmax≥3cm,n=13）for study.The iodine concentration（IC）,normalized iodine concentration（NIC）,effective atomic number(Z_eff),slope of energy spectrum curve(K_{40¹00ke V})and single energy CT values of 40～100ke V（interval 10ke V）were measured,calculated and analyzed.The data were analyzed using statistical methods:one-way analysis of variance and independent sample t-test.Draw the receiver operator characteristic curve（ROC）of the subject,calculate the area under the curve（AUC）and analyze the efficiency of spectral CT parameters in differentiating lung adenocarcinoma and non-lung adenocarcinoma,non-small cell lung cancer and small cell lung cancer,lung adenocarcinoma with different degrees of differentiation and moderately-highly differentiated lung adenocarcinoma and poorly differentiated lung adenocarcinoma with Dmax≥3cm,and calculate the sensitivity,specificity,Youden index and 95%confidence interval（CI）.Spearman correlation coefficient was used to analyze the correlation between the spectral parameters of moderately-highly differentiated lung adenocarcinoma and poorly differentiated lung adenocarcinoma in the venous phase and the Dmax.Results:IC,NIC,Z_eff,K_{40-100ke V}and CT_{40ke V}in venous phase of lung adenocarcinoma were higher than those in squamous cell carcinoma and small cell lung cancer;CT_{50ke V}and CT_{60ke V}in venous phase of small cell lung cancer were lower than those in lung adenocarcinoma;The NIC in arterial phase of small cell lung cancer was lower than that in lung adenocarcinoma,and the differences were statistically significant（P<0.05）.IC,NIC,Z_eff,CT_{40ke V},CT_{50ke V},CT_{60ke V},CT_{70ke V},CT_{80ke V}and CT_{90ke V}in venous phase of poorly differentiated lung adenocarcinoma were lower than those in moderately-highly differentiated lung adenocarcinoma,and the differences were statistically significant（P<0.05）.IC,NIC and Z_effin venous phase in group Ib were lower than those in group Ia;IC,NIC,Z_eff,CT_{40ke V},CT_{50ke V},CT_{60ke V},CT_{70ke V}and CT_{80ke V}in venous phase in group IIb were lower than those in group IIa,and the differences were statistically significant（P<0.05）.Spearman correlation coefficient analysis showed that the correlation coefficients between Dmax of lung adenocarcinoma and IC,NIC and Z_effin venous phase of moderately-highly differentiated group respectively were-0.497,-0.654 and-0.445,P<0.05;The correlation coefficients between Dmax of lung adenocarcinoma and IC,NIC,Z_eff,CT_{40ke V},CT_{50ke V},CT_{60ke V},CT_{70ke V}and CT_{80ke V}in venous phase of poorly differentiated group respectively were-0.648,-0.721,-0.628,-0.474,-0.546,-0.517,-0.474 and-0.444,P<0.05.The NIC in venous phase in group IIa was lower than that in group Ia;IC,NIC,Z_eff,CT_{40ke V},CT_{50ke V},CT_{60ke V},CT_{70ke V}and CT_{80ke V}in venous phase in group IIb were lower than those in group Ib,and the differences were statistically significant（P<0.05）.When ROC was plotted,the maximum AUC of K_{40¹00ke V}in venous phase for diagnosis of lung adenocarcinoma and non-lung adenocarcinoma was 0.815,and the diagnostic threshold,sensitivity and specificity were 1.505,92.9%and 65.2%,respectively.The maximum AUC of K_{40-100ke V}in venous phase for diagnosis of non-small cell lung cancer and small cell lung cancer was 0.768,and the diagnostic threshold,sensitivity and specificity were 1.418,76.4%and 75.0%,respectively.The maximum AUC of NIC in venous phase for diagnosis moderately-highly differentiated lung adenocarcinoma and poorly differentiated lung adenocarcinoma was 0.898,and the diagnostic threshold,sensitivity and specificity were0.306,90.0%and 77.3%,respectively.The maximum AUC of NIC in venous phase for diagnosis of group Ib and group IIb was 0.932,and the diagnostic threshold,sensitivity and specificity were 0.279,88.9%and 92.3%,respectively.Conclusion:The quantitative parameters of DSCT have certain reference value in the evaluation of different pathological types of lung cancer and different degrees of pathological differentiation of lung adenocarcinoma.The spectral parameters of moderately-highly differentiated lung adenocarcinoma and poorly differentiated lung adenocarcinoma in the venous phase were negatively correlated with the Dmax.For moderately-highly differentiated lung adenocarcinoma and poorly differentiated lung adenocarcinoma with Dmax≥3cm,multiple spectral parameters in venous phase showed inter-group differences,while for lesions with Dmax<3cm,only NIC in venous phase showed inter-group differences.