Initial Study On The Value Of The Multi-parameter Analysis Of Spectral CT In Evaluating Pathological Types And Stages Of Lung Cancer

Objective To investigatethe application value of the multi-parameter analysis of spectral CT in evaluating pathological types and stages of lung cancer.Methods 63 patients with lung cancer confirmed by surgery or biopsy in the Provincial Hospital affiliated of Anhui Medical University were selected.There are 38 cases of adenocarcinoma,including 12 cases of poorly differentiated adenocarcinoma,22 cases of moderately differentiated adenocarcinoma,2 cases of high differentiated adenocarcinoma,2 cases of middle and high differentiation.Meanwhile there are 25 cases of squamous cell carcinoma including 16 cases of poorly differentiated and 9 cases of moderate differentiated squamous cell carcinoma.GE gemstone spectroscopic CT discovery CT750(HD)scanner was used to scan all patients.The single energy image was reconstructed by 1.25 mm thin layer and transmitted to the adw4.6 workstation.The multiparameter measurement and data recording of the image were performed using GSI viewer software.The CT values of all lesions ROI were measured at 40-90 ke Vs(10 ke Vs interval)in arterial phase,venous phase and delayed phase.The iodine content and the effective atomic number,the energy spectrum curve of the lesion were plotted.The slope of the energy spectrum curve,the standardized iodine concentration(NIC)of the lesions were calculated.The data of lung adenocarcinoma,squamous cell carcinoma,low differentiation and high differentiation group were statistically compared and analyzed by t test of two independent samples.The ROC curve was drawn.The area under the curve(AUC)is calculated and the diagnostic effectiveness of each index is analyzed,and the optimal diagnostic threshold is selectedby means of the Youden index.Results All cases were divided into two groups: lung adenocarcinoma group and lung squamous cell carcinoma group.The same pathological type groups were divided into low differentiation group and middle or high differentiation group.The corresponding CT values of lung cancer at different single energy level decreased with the increase of energy level,and the CT values in adenocarcinoma group at 40 ke V-70 ke V level were higher than those in squamous cell carcinoma group.The difference of CT values at 40 ke V and 50 ke V were statistically significant(p < 0.05).The slope of energy spectrum curve and the concentration of standardized iodine in adenocarcinoma group were higher than those in squamous cell carcinoma group.The difference was statistically significant(p < 0.05),and the difference of effective atomic number between lung adenocarcinoma group and squamous cell carcinoma group was also statistically significant(p < 0.05).The standardized iodine concentration,the slope of the energy spectrum curve and the effective atomic number in the low differentiation group were slightly lower than those in the middle and high differentiation group,and the difference was statistically significant(P < 0.05).There were no significant differences in standardized iodine concentration,slope of energy spectrum curve and effective atomic number between poorly differentiated and moderately well differentiated lung squamous cell carcinoma patients three-phase scanning,and there were no significant differences in lung adenocarcinoma invenous phase and delayed phase.ROC curve analysis showed that the areas under the curve of the slope of the energy spectrum curve,the standardized iodine content and the effective atomic number of lung adenocarcinoma and squamous cell carcinoma were greater than 0.5 in three-phase scanning.The areas under the curve of the standardized iodine concentration,the slope of the energy spectrum curve and the the effective atomic number were all greater than 0.5 in different differentiation groups of lung adenocarcinoma.Especially when the slope of the energy spectrum curve in the venous phase is less than 2.073 and the slope of the energyspectrum curve in the delayed phase is less than 2.18,the specificity of diagnosis of lung adenocarcinoma is as high as 92.0% and 88.0%.When the effective atomic number of delayed phase is less than 8.12,the sensitivity of the diagnosis of lung adenocarcinoma is 94.7%.Conclusion The characteristic of energy spectrum attenuation CT curve,the slope of energy spectrum curve,the standardized iodine concentration and effective atomic number have certain reference value for the evaluation of different pathological classification and grade of lung cancer,and have certain guiding significance for the diagnosis and qualitative analysis of lung cancer.