| Part ⅠDual-energy CT venous stage iodine map and fusion image serosal enhancement sign to diagnosis of T3 stage and T4a stage gastric cancerObjective:To investigate the efficacy of dual-energy CT venous phase iodine map and fusion image in the diagnosis of T3 and T4a stage gastric cancer using serosal enhancement sign.Methods:A total of 82 cases of stage T3 and T4a gastric cancer confirmed by pathology in our hospital from June 2017 to January 2019 were retrospectively collected.All of these patients had complete abdominal dual-energy CT scan image data.By observing and comparing the incidence of serosal enhancement sign in venous phase iodogram and venous phase fusion image,the presence of serosal enhancement sign was used as the criteria for the diagnosis of stage T4a gastric cancer.The positive predictive value,negative predictive value,accuracy,specificity and sensitivity of venous phase iodogram and venous phase fusion image in the diagnosis of stage T3 and T4a gastric cancer were calculated,respectively.Results:Of the 82 gastric cancer cases included,a total of 27 were T3 gastric cancer and 55 were T4a gastric cancer.The accuracy,sensitivity,specificity,negative predictive value,and positive predictive value of displaying serosal enhancement sign using venous phase iodine map,venous phase fusion image,and combined venous phase iodine map and fusion image in the diagnosis of T4a stage gastric cancer were 78.04%(64/82),81.81%(45/55),70.37%(19/27),65.51%(19/29),84.90%(45/53),74.39%(61/82),72.72%(40/55),77.77%(21/27),58.33%(21/36),86.95%(40/46),89.02%(73/82),90.90%(50/55),85.18%(23/27),82.14%(23/28),and 92.59%(50/54),respectively.The positive rates of venous phase iodogram,venous phase fusion image,combined venous phase iodogram and fusion image showing serosal enhancement sign in differentiating T4a stage gastric cancer were 81.81%,72.72%and 90.90%,respectively.The positive diagnostic rates of combined diagnosis and venous phase iodogram were higher than those of venous phase fusion images,and there was significant difference between the above two groups(P<0.05),but there was no significant difference in the positive rate between venous phase iodogram and combined diagnosis(P=0.16).Conclusion:Dual-energy CT venous phase iodogram shows that the detection rate of serosal enhancement sign in differentiating T4a stage gastric cancer is higher than that of corresponding fusion image.It is recommended to use venous phase iodogram or combined venous phase iodogram and fusion image to observe this sign,and the accuracy rate obtained is high.Part ⅡThe Value of Dual-energy CT in Measuring Tumor Volume and Iodine Concentration in Prediction of Lymph Node Metastasis in Gastric CancerObjective:To investigate the efficacy of dual-energy CT(DECT)in measuring tumor volume in venous phase gastric cancer and iodine concentration in venous phase of primary tumor in predicting regional lymph node metastasis and predicting N stage.Methods:A total of 91 patients with gastric cancer from June 2018 to May 2020 in our hospital were retrospectively collected.The patients were included in this study and underwent preoperative dual-energy CT scanning with complete image data.Based on the pathological results as the gold standard and confirmed by pathology with or without lymph node metastasis,the patients were divided into metastatic lymph node group and non-metastatic lymph node group.The tumor volume and iodine concentration of venous gastric cancer were measured by dual-energy CT post-processing workstation.The differences in the values were compared by two independent samples t-test.If the obtained parameters were statistically significant,the corresponding ROC curve(ROC)was further drawn.The diagnostic efficacy and diagnostic threshold of different parameters were calculated.For lymph node metastasis group,the correlation between iodine concentration in venous phase of gastric cancer and N stage was further judged and ROC curve was drawn.The efficacy of N stage was calculated and evaluated.Results:Of the 91 patients with gastric cancer included,24 were in the group without metastatic lymph nodes and 67 were in the group with metastatic lymph nodes,including 24,18,22,and 27(12 N3a and 15 N3b)in stages N0,N1,N2,and N3,respectively.The tumor volume and iodine concentration of venous gastric cancer in the group without lymph node metastasis were(8.68±5.53)cm3 and(1.43±0.39)mg/ml,respectively;the tumor volume and iodine concentration of venous gastric cancer in the group with lymph node metastasis were(20.36±14.83)cm3 and(2.17±0.61)mg/ml,respectively.There were significant differences in the tumor volume and iodine concentration parameters of gastric cancer between the above two groups(P<0.05).The area under the curve(AUC)of tumor volume and iodine concentration in venous gastric cancer for the diagnosis of lymph node metastasis was 0.80 and 0.82,respectively,and the diagnostic thresholds were 10.33 cm3 and 1.57 mg/mL,respectively.There was a positive correlation between iodine concentration in the venous phase of gastric cancer tumors and N stage(rs=0.945,P<0.05),and its area under the curve and diagnostic threshold for distinguishing NO～(N1-N3),(N0-N1)～(N2-N3),and(N0-N2)～N3 were 0.82,0.85,0.79,1.57mg/mL,1.65 mg/mL,and 2.15 mg/mL,respectively,and the differences were statistically significant(P<0.05).There was no significant difference in iodine concentration between N3a and N3b groups(P>0.05).Conclusion:Dual-energy CT measurement of tumor volume in venous phase and iodine concentration in venous phase of primary tumor is helpful to evaluate lymph node metastasis and provide the basis and reference for preoperative N staging of gastric cancer.Part ⅢApplication of quantitative parameters of dual-energy CT in evaluation of differentiation degree of gastric cancerObjective:To investigate the diagnostic value of iodine concentration,standardized iodine concentration and slope of spectral curve in venous phase of dual-energy CT for preoperative differentiation of gastric cancer.Methods:A total of 58 patients with gastric cancer were retrospectively included.The collected patients had complete imaging data of dual-energy CT scan,and were pathologically diagnosed with gastric cancer after operation.According to the pathological results,the included cases were divided into well-differentiated group(15 cases confirmed as well-differentiated and moderately well-differentiated gastric cancer by pathological results),moderately differentiated group(20 cases confirmed as moderately differentiated and moderately poorly differentiated gastric cancer by pathological results)and poorly differentiated group(23 cases confirmed as poorly differentiated gastric cancer by pathological results).Completely random analysis of variance and LSD-t test were used to analyze the differences in the slopes of iodine concentration(IC,Iodine Concentration),standardized iodine concentration(NIC,Normalized Iodine Concentration)and(40-70 KeV)energy spectrum curves.If the differences in the parameters used were statistically significant,the corresponding ROC curves were further plotted,the area under the curve(AUC)was calculated,and the diagnostic efficacy of the above parameters in the diagnosis of gastric cancer with different degrees of differentiation was evaluated.Results:The slopes of IC,NIC and(40-70KeV)λHu in well-differentiated group were(1.87±0.24)mg/ml,(0.17±0.05)and(1.87±0.31),respectively;the slopes of IC,NIC and(40-70KeV)λHU in moderately differentiated group were(2.05±0.26)mg/ml,(0.15±0.04)and(2.25±0.38),respectively;the slopes of IC,NIC and(40-70KeV)λHU in poorly differentiated group were(2.49±0.47)mg/ml,(0.28±0.09)and(2.68 ±0.43),respectively.The slopes of IC,NIC and(40-70 KeV)λHU in the well-differentiated group were lower than those in the poorly differentiated group,and the differences were statistically significant(all P<0.05);there was no significant difference in IC in the venous phase between the moderately differentiated and well-differentiated groups(P=0.162),while there was a significant difference in the slopes of NIC and(40-70 KeV)λHU between the two groups,and the differences were statistically significant(all P<0.05).Further plotting the ROC curve(Figure 4A-C)revealed that the diagnostic sensitivity and specificity of IC,NIC,and λHU in the venous phase(well differentiated\moderately differentiated)and poorly differentiated groups were high,86.6%,82.7%,83.6%,80.0%,87.3%,and 85.0%,respectively.In addition,the accuracy of NIC and λHU in the diagnosis of moderate and poor differentiation groups was high,81%and 80%,respectively,with(40-70 Kev)λHU having the best diagnostic efficacy.Conclusion:The slope of dual-energy CT spectral curve,iodine concentration and standardized iodine concentration are easy to obtain,of which IC,NIC and λHU in venous phase have higher sensitivity and specificity in the diagnosis of poorly differentiated gastric cancer,NIC and λHU have higher accuracy in the diagnosis of moderately differentiated and poorly differentiated groups,of which(40-70Kev)λHU has the best diagnostic efficacy. |
PDF Full Text Request