MDCT Features Of T2 Gastric Cancer

Objective 1.To study the value of enhanced multidetector-row CT(MDCT)in detection of the T2 gastric cancer and clinicopathology features of the T2 gastric cancer. 2. To explore the value of MDCT in the preoperative TNM staging of T2 gastric cancer.3.To determine the optimal cut-off value of lymph node size for diagnosing metastasis in gastric cancer with MDCT.Methods Ninety three patients were included in our study and underwent MDCT scanning, who were confirmed by pathologic results.1.The thickness of the mucosa of gastric wall, its changes of enhanced CT value in triphases and also clinicopathology features of the T2 gastric cancer were analyzed.2. The TNM staging results were compared with those of pathologic TNM staging.3. The long-axis diameter(LAD) and short-axis diameter(SAD) of all visualized lymph nodes were measured with transverse MDCT images. The locations of lymph nodes were categorized into two regions: lesser curvature and greater curvature. The diagnostic value of lymph node metastasis was assessed with receiver operating characteristic(ROC) analysis and area under curve(AUC).Results 1.There are no statistically significant differences on clinicopathology features among T2 a and T2 b patients(P(29)0.05). All ninety three T2 gastric cancer patients show the thickening of stomach wall with a different degree. The thickness of gastric mucosa(5.44±1.58mm)in early gastric cancer patients was more thick than that(2.27±0.50mm)in control group(t=10.812,p(27)0.0001).There were statistically significant differences in the changes of CT value between T2 gastric cancer patients and normal wall in arterial,portal venous and equilibrium phases(t=2.336,P=0.021;t=4.661,P(27)0.0001;t=3.480,P=0.0001).2. Comparing with pathologic TNM stage,the T staging accuracy of MDCT was 91.40(4),the N staging accuracies of CT was 66.67(4)(among them, 68.18(4)(30/44), 65.00(4)(26/40), 60.00(4)(3/5) and75.00(4)(3/4) for p N0, p N1, p N2 and p N3)and the TNM staging accuracies of CT was67.74(4)(among them, 68.18(4)(30/44),64.10(4)(25/39), 60.00(4)(3/5) and 100(4)(5/5) for stage I, II, III and IV).3. The area under the curve was larger for SAD than LAD in all groups. The optimal cut-off values of SAD were determined as follows: overall, 5.45 mm; differentiated type, 5.65 mm; undifferentiated type, 4.85 mm; lesser curvature region, 5.55 mm and greater curvature region, 5.05 mm. The diagnostic accuracies for lymph node metastasis using individual cut-off values were 80.6 % based on histological type and 80.6 % based on region of lymph node location.Conclusion 1.MDCT can provide useful information to improve the diagnosis of T2 gastric cancer. There are no significant differences on clinicopathology features among T2 a and T2 b patients. 2.MDCT can clearly determine the preoperative TNM staging of T2 gastric cancer.3. The diagnostic accuracy of lymph node metastasis in gastric cancer was improved by using of individual cut-off values.