The Research Of Spectral CT In Evaluation The Pathological Types Of Gastric Adenocarcinoma

Objective:To explore the diagnostic value of spectral CT imaging in the quantitative evaluation of different pathological types of gastric cancer,and to further investigate the diagnostic value of quantitative parameters of spectral CT imaging and gender,age,lesion location,lesion size,ulcer,peritumoral fat clearance change and tumor growth modes in evaluating the different degree of differentiation in gastric adenocarcinoma,and to provide the imaging diagnosis basis for assessing the clinicopathological features of gastric cancer patients.Materials and Methods:The institutional review board of the first affiliated hospital of Zhengzhou university approved this prospective study;all patients provided written informed consent.A prospective study of 132 patients(89 men,43women;age range 26-79,average age 57.7)with gastric cancer confirmed by surgical pathology from August 2015 to June 2016,who underwent preoperative CT scan on GE Discovery CT that included normal unenhanced scan and dual-phase(arterial phase and venous phase)enhanced scan with gemstone spectral imaging(GSI)mode.All the images were analyzed on the workstation of ADW4.6 and all measurements were performed on the GSI viewer software.The CT values(HU)of gastric cancer lesions were measured on unenhanced scan and dual-phase enhanced scan that under the single energy of 40 ke V,65 ke V and 100 ke V.The iodine concentration(IC,100ug/cm3)and the water concentration(WC,mg/cm3)of the primary lesion and the IC(100ug/cm3)of aorta were measured.Then the normalized iodine concentration(NIC)and the slope of spectral curve(k)were calculated.At the same time,the maximum diameter and thickness of the lesion were measured.The location of the lesion,the ulceration of the lesion,the growth pattern and the infiltration of peritumoral fat clearance were observed and recorded.All the values of CT,IC,WC,NIC and k in the primary lesion were recorded and assessed by analysis of variance(ANOVA).Using LSD-t method to compare the parameters between the two groups.Independent samples t test was used to analyze the corresponding quantitative parameters of non-mucinous adenocarcinoma;the parameters of CT images and gender were analyzed by chi-square test.Receiver operating characteristic(ROC)was used to determine the diagnostic efficiency of the corresponding parameters.Results:There were 132 patients with gastric cancer confirmed by surgical pathology,including mucinous carcinoma in 27 cases,mixed adenocarcinoma in 28 cases,and non-mucinous adenocarcinoma in 77 cases(including well-differentiated adenocarcinoma in 4 cases,moderately-differentiated adnocarcinoma in 28 cases,and poorly-differentiated adenocarcinoma in 45 cases).There was no significant difference in age between different pathological types of gastric adenocarcinoma(F=2.997,P=0.053).Univariate analysis of variance showed that in all phases the CT values of the non-mucinous adenocarcinoma group were higher than those of the mucinous adenocarcinoma group and the mixed adenocarcinoma group.The CT values of the mixed adenocarcinoma were higher than those of the mucinous adenocarcinoma in arterial phase and venous phase,and they were similar in plain scan between two groups.But only thedifferent pathological types of the lesions of CT value in venous phase was statistically significant(P<0.05),further comparison showed that only the venous phase CT values between mucinous carcinoma group and non mucinous adenocarcinoma group had significant difference(P<0.05).The IC,NIC and the slope of spectral curve of the mucinous adenocarcinoma,the mixed adenocarcinoma and the non-mucinous adenocarcinoma in arterial phase and venous phase showed an increasing trend,and the difference among the three groups was statistically significant(all P < 0.05).Further comparison showed that the IC,NIC and k of the mucinous adenocarcinoma group were lower than those of the non-mucinous adenocarcinoma group,and the difference were statistically significant(all P < 0.05).The corresponding energy spectrum parameters in the mixed adenocarcinoma had no significant difference with the mucinous adenocarcinoma group and with non-mucinous adenocarcinoma group,neither(P > 0.05).Further research showed that the CT values of the poorly differentiated adenocarcinoma group were higher than that of the well and moderately differentiated adenocarcinoma group in each phase,but the difference was not statistically significant(all P >0.05).The maximum diameter and thickness of the lesion in the poorly differentiated adenocarcinoma group were significantly higher than those in the moderately differentiated adenocarcinoma group(all P <0.05).The IC,NIC,WC and k values of the lesions in the middle and high differentiation adenocarcinoma group were lower than those of the poor differentiation adenocarcinoma group in arterial phase and venous phase,but Significant difference of IC,NIC and k were only found between two groups in venous phase.The ROC curves of the IC,the NIC and the slope of the energy spectrum curve in venous phase were plotted,and the NIC in venous phase had the largest area under the curve.The results of chi-square test showed that the location of gastric cancer,the ulceration of the lesion and tumor growth pattern were all no significant difference in the different differentiation degree of gastric adenocarcinoma(all P <0.05).The difference of gender and tumor growth pattern between patients with poorly differentiated gastric adenocarcinoma and well-moderately differentiated gastric adenocarcinoma was statistically significant,and the age and the gender and the change of peritumoral fat gap were the relevant factors affecting the differentiation of gastric adenocarcinoma.Conclusion:The blood supply of gastric adenocarcinoma is affected not only by different pathological types,but also by the degree of differentiation.The iodine concentration,the standard iodine concentration and the slope of spectral curve in arterial and venous phase can be used to identify mucinous adenocarcinoma and mucinous adenocarcinoma.And the iodine parameters of the lesion(IC,NIC)and the slope of the spectral curve in venous phase have certain value in distinguishing the degree of differentiation of gastric adenocarcinoma.Meanwhile the age and gender of patients and the change of peritumoral fat gap are also related to the differentiation of gastric adenocarcinoma.