Application Value Of Dual-source CT In Tnm Staging Of Colorectal Cancer

Objective:To evaluate the value of dual source CT in TNM staging of colorectal cancer.Materials and methods: Fifty-five patients with colorectal cancer confirmed by operation and pathology in our hospital from July 2018 to December 2019 were collected,of which 46 cases with complete clinical and image data and good image quality were included in the study.A total of 47 colorectal cancer lesions were found.All patients were scanned by dual-source CT and the data were measured and analyzed in dual-energy tool software.Combined with the eighth edition of TNM staging system for colorectal cancer,CT-TNM staging was carried out.Because CT could not distinguish the layers of the intestinal wall,T staging was divided into T ? 2,T3 and T4 stages.The following data are mainly measured:(1)the long diameter,short diameter and short-length ratio of lymph nodes in accordance with the inclusion criteria.(2)the iodine value,overlay value and the iodine concentration of aorta or iliac artery in different lesions,lymph nodes,T3 and T4 perifocal and normal periintestinal fat spaces were measured and the standardized iodine concentrations were calculated.(3)the single energy CT values of different lesions,lymph nodes,T3 and T4 perifocal fat spaces and normal periintestinal fat spaces were measured under different Ke V,and the slope of energy spectrum curve was calculated.According to the postoperative pathology,the lymph nodes were divided into metastatic lymph node group and non-metastatic lymph node group;according to the postoperative pathology,the lymph nodes were divided into vascular / nerve invasion group and non-invasion group.Preoperative T and M staging were performed with single energy image and compared with pathological staging.One-way ANOVA was used to compare the differences of energy spectrum parameters between T3,T4 and normal fat spaces;independent sample T test was used to compare the differences of energy spectrum imaging parameters between metastatic lymph nodes and non-metastatic lymph nodes,between vascular / nerve invasion group and non-invasion group,and between metastatic lymph nodes and their foci.Chi-square test was used to compare the difference between vascular invasion and lymph node metastasis.When P < 0.05,the difference was statistically significant.The ROC curve was drawn with statistically significant parameters and its diagnostic efficiency was analyzed.RESULTS: 1.Single-energy image preoperative T and M staging compared with pathological staging and diagnostic efficiency: 47 lesions of 46 patients were observed and staged by single-energy imaging,and then CT staging was compared with pathological staging.The results showed that the accuracy of T ? 2,T3 and T4 were90.91%,82.14% and 75%,respectively.The accuracy of M0 and M1 was 100%.2.Comparison of energy spectrum parameters of T3,T4 and normal periintestinal fat space: there were significant differences in energy spectrum parameters of T3,T4 and normal periintestinal fat space in arteriovenous phase(P< 0.01).Among the parameters,the diagnostic efficacy of venous phase overlay value and the slope of venous phase energy spectrum curve for the differential diagnosis of T3 and T4 was significantly higher than other parameters,the area under the curve was 0.795 and 0.813 respectively,and the diagnostic threshold was 15.800(HU)and 0.723,respectively.3.Comparison of morphological and energy spectrum parameters between metastatic lymph nodes and non-metastatic lymph nodes: there were significant differences in long diameter and short diameter between metastatic lymph nodes and non-metastatic lymph nodes(P < 0.01).There was no significant difference in the ratio of short to long(P < 0.05).There were significant differences in iodine value,Overlay value,standardized iodine concentration and slope of energy spectrum curve between metastatic lymph nodes and non-metastatic lymph nodes in arteriovenous phase(P <0.05).Among the diagnostic efficiency indexes of various energy spectrum parameters,the diagnostic efficiency of venous phase overlay value and venous phase standardized iodine concentration was significantly higher than other parameters,the area under the curve was 0.860 and 0.794 respectively,and the diagnostic threshold was 46.400(HU)and 0.452 respectively.4.Comparison of energy spectrum curve between metastatic lymph node and its focus:there was no significant difference in energy spectrum curve and slope of energy spectrum curve between metastatic lymph node and its focus in arteriovenous phase(P > 0.05).5.Comparison of energy spectrum parameters between vascular / nerve invasion group and non-invasion group: there was no significant difference in energy spectrum parameters between vascular / nerve invasion group and non-invasion group(P >0.05).6.Correlation between vascular / nerve invasion and lymph node metastasis:Chi-square test showed that vascular / nerve invasion was correlated with lymph node metastasis(P < 0.05).Conclusion:1.Single-energy images preoperative T and M staging and pathological stage contrast and diagnostic efficacy: single-energy images were used to observe 47 lesions in 46 patients with T and M staging,then CT staging and pathological staging were compared.The results showed that the accuracy of T ?2 stage,T3 stage and T4 stage were 90.91%,82.14% and 75%,respectively.M0 and M1 are 100% accurate.2.There were significant differences in iodine value,overlay value,standardized iodine concentration and slope of energy spectrum curve between perifocal and normal periintestinal fat space in arteriovenous phase T3 and T4.The diagnostic efficacy of venous overlay value and slope of energy spectrum curve in the differential diagnosis of T3 and T4 was significantly higher than that of other parameters.3.The short and long diameter of lymph nodes,arteriovenous iodine value,overlay value,standardized iodine concentration and slope of energy spectrum curve are valuable in differentiating metastatic lymph nodes from non-metastatic lymph nodes,and the diagnostic efficacy of venous phase overlay value and venous standardized iodine concentration is the highest.4.There is no statistical significance in the comparison of energy spectrum curves between metastatic lymph nodes and their lesions.5.The comparison of energy spectrum parameters between the vascular / nerve invasion group and the non-invasion group was not statistically significant.6.There was a correlation between vascular / nerve invasion and lymph node metastasis.