| Objective :To study the accuracy of multi-slice spiral CT in the diagnosis of N-staging and different regions metastasis lymph nodes of gastric cancer by analysis the short-axis diameter 、the ratio of shortdiameter to long diameter、shape and density.Methods :Pathology and CT imaging materials of 91 patients with biopsy proved gastric cancer were recruited.MSCT were performed with plain and triphasic dynamic contrast enhancement before surgery,Using SIEMENS Siemens Sensation 64 and PHILPS Briliance spiral CT,Scanning parameters:Voltage:120 kV,Electric current:220~250 m As,Thick layer:0.625 mm and 0.5mm;All patients were examined with fasting 8 h,Intramuscular injection of anisodamine hydrochloride(654-2)20mg 10 minutes before CT scan,Oral warm water 800 ~ 1000 mL to fill the stomach.Supine scan,then,a non ionic contrast agent was injected into the cubital vein(Iodine concentration270 mg/100 ml),Total injection:1.5 ml/kg,Injection speed :3.0 ml /s,Arterial phase images were acquired at 35 s after contrast injection,venous phase images were acquired after 70 s,Scan range from the top of the diaphragm to the lower edge of the liver or stomac,After scanning,the axial 3 mm soft tissue window reconstruction was performed in plain、 arterial and venous phase images,and reconstruction of 3 mm soft tissue window of coronal plane in venous phase.Different regions metastasis lymph nodes and N-staging were evaluated by using the proposed combined diagnostic criterias(The short diameter of the lymph nodes ≥5 mm,and the ratio of short diameter and long diameter≥0.7,and have the flat CT value≥25 HU.Or mild or moderate enhancement(Venous phase≥75 HU);Or although do not have the above conditions but multiple lymph nodes mutual fusion)and then correlated with that of pathology.Kappa consistency test was used to study the accuracy.Results :(1)The accuracy of N-staging as a whole was 86.3%.The accuracy of N0、N1、 N2 and N3 was 83.5%、89.0%、83.5%、89.0%,respectively.The sensitivity for N0、N1、N2 and N3 was 86.5%、83.3%、50%、47.4%,respectively.The specificity for N0、N1、N2 and N3 was79.5%、89.4%、89.6%、100%,respectively.The difference of sensitivity between N0 and N2 、N0 and N3 were statistically significant(P≤ 0.007).(2)The accuracy of MSCT for different regions metastasis lymph nodes was79.1%-98.9%,especially for N0.2(Left cardiac)、N0.10(Hilum of spleen)、N0.13(Retropancreas),the accuracy was 98.9%,higher than other groups of lymph nodes,While N0.3(Lesser curvature)with low accuracy of 79.1%;The sensitivity for N0.2(Left cardiac)、N0.9(Coeliac trunk)、N0.10(Hilum of spleen)、N0.13(Retropancreas)was higher,can reach 98.9%,While N0.8(Common hepatic artery)with low sensitivity of 50%;The specificity for N0.2(Left cardiac)、N0.10(Hilum of spleen)、N0.13(Retropancreas)was higher,can reach 98.9%,While N0.8(Common hepatic artery)with low specificity of 87.1%;T he Positive predictive value for NO.3(Lesser curvature)was higher,can reach 85.7%,While N0.8(Common hepatic artery)and N0.12(Hepatic duodenum ligament)with low Positive predictive value of 21.4% and22.2%,respectivly;The negative predictive value for NO.2(Left cardiac)、NO.9(Coeliac trunk)、NO.10(Hilum of spleen)、 NO.13(Retropancreas)was higher,can reach 100%,While NO.3(Lesser curvature)with low negative predictive value of 76.2%.The judgment of groups of lymph nodes metastasis of both MSCT at preoperative and postoperative pathological have good consistency(Ktotal=0.567).(3)Analying the relationship between T staging and the N staging of gastric cancer,found that 12 patients with T1a-T1b(Tumor invasion the mucosal lamina propria 、 Mucosal muscularis or submucosa),but no obviously metastasis lymph nodes found around the stomach;23 patients with T2(Tumor invasion the muscularis propria),There were 1(about4.3%)of the patients with N1;27 patients with T3(Tumor penetrating connective tissue),There were 4(about 14.8%)of the patients with N1,6(about 22.2%)of the patients with N2,5(about18.5%)of the patients with N3;29 patients with T4a-T4b(Tumor invasion of serous or adjacent tissue structures),There were 2(about 6.9%)of the patients with N1,7(about24.1%)of the patients with N2,14(about 48.3%)of the patients with N3.Correlation analysis of T staging and N staging showed that P < 0.001,so there was a linear relationship between T staging and N staging,and the relationship strength was 0.641,which was positively correlated.It can be seen that with the increase of T staging,the risk of lymph node metastasis in patients with gastric cancer is also increased.Conclusion :(1)Using the combined diagnostic criterias MSCT has high accuracy in the N staging andlymph node metastasis of gastric cancer in the preoperative。(2)The diagnostic accuracy of N0.2(Left cardiac)、 N0.10(Hilum of spleen)、N0.13(Retropancreas)were higher than that of other groups;The sensitivity of N0.2(Left cardiac)、N0.9(Coeliac trunk)、N0.10(Hilum of spleen)、N0.13(Retropancreas)were higher than that of other groups;The Specificity of N0.2(Left cardiac)、 N0.10(Hilum of spleen)、N0.13(Retropancreas)were higher than that of other groups。(3)With the increase of T staging of gastric cancer,the risk of lymph node metastasis in patients with gastric cancer is also increased,and with the increase of T staging,N staging also increased. |
