| Objectives: To make clear the metastatic rule and characteristic oflymph node in Colorectal Cancer and there is a certain difference in imagingwhether lymph node metastasis or not. A study was made to assess the ruleand characteristics of lymph node by MDCT. Hoping to offer more imaginginformation for clinical colorectal cancer Lymph node N staging and relatedtreatment.Methods:1. We performed a retrospective analysis of Affiliated Hospital ofMedical College from October,2011to December,2013with the whole colonMDCT examination. Under the condition of meetting the inclusion criteriaand exclusion criteria,101patients were recorded as a group of normalcontrol finally.2. Routine scanning was applied by the America GE128sliceMulti-detector spiral CT(Model: Light Speed VCT). The tube voltage was120Kv; tube current was200mA; rotation speed was39.37mm/rot; rotationtime was0.6s; matrix was512×512; standard filter function was FC10; andpitch factor was0.984; collimator width was0.625×64; reconstructionthickness was0.625mm；reconstruction interval was0.300mm.3. All patients make conventional gastrointestinal preparation beforeexamination, the scanning (range from the top of diaphragm to the inferiorsymphsis pubis). All the patients signed informed consent, and all theexamination was under supervision by hospital ethics committee. 4. These data of scanning imaging by MDCT were processed on theAW4.5post-processing workstation. The lymph nodes were detected by thetwo dimensional mulitiple imaging of MDCT. According to the relevantliterature, all the indexes(the size, density, anatomy,enhancement degree) ofthe lymph node were better observated clearly. All the datas were recordedand measured, and all values were statistically analysed then.Results:1.The diagnostic of accuracy of N0,N1,N2were89.3%(50/56),59.1%(13/22),78.3%(18/23); And total accuracy was80.2%(81/101) by MDCT.The sensitivity of MDCT for evaluating lymph node metastasis was93.3%(42/45), specificity was89.3%(50/56), positive predictive value was87.5%(42/48), negative predictive value was94.3%(50/53), with thechi-square test and kappa test, P<0.05, K value=0.672. A medium consistencyexist between the manifestation of the colon on MDCT and operativepathology N staging. MDCT can evaluate the N staging of the colorectalcancer.2. Non metastatic lymph node(N0staging),the average of the largestshort diameter were4.25±1.47mm, the lymph node detected were1.94±0.97piece per person; The metastatic lymph node(N1.2), for N1staging, theaverage of the largest short diameter were8.19±2.04mm, the lymph nodedetected were6.31±1.24piece per person; for N2staging, the average of thelargest short diameter were10.05±2.23mm, the lymph node detected were6.61±1.10piece per person. The two independent samples t test has statisticalsignificance, P<0.05, the two differences have statistical significance.3. The CT value of the non metastatic lymph node with plain CTscanning were28.37±2.06HU, and then the CT value was57.38±2.73HU after enhanced CT scanning. The CT value of the metastatic lymph node(N1,2)with plain CT scanning were partly30.11±2.77HU,33.12±3.05HU,and then the CT value were partly67.92±4.15,70.37±4.55HU after enhancedCT scanning. The two independent samples t test, P<0.05, the two differenceshave statistical significance.4. The lymph node metastatic rate and ratio of station Ⅱ、 Ⅲwerecompared with stationⅠ,P<0.05, their difference has statisticalsignificance.The result suggests that the dominant anatomic distribution ofthe metastatic lymph node were in the nearest pericolorectal nodal area whichwas significantly higher than other stations anatomic distribution. Theanatomic distribution of the non metastatic lymph node, P>0.05, theirdifference has no statistical significance.To statistics the metastasis of the lymph node which lied in the left halfcolon caner and the right half colon cancer with station Ⅰ and station Ⅱ+Ⅲ,the results suggests that the lymph node rate of the left colorectal cancerwas lower than of the right; Whether in the nearest pericolorectal nodal area,around mesentery or in mesenteric roots,the lymph node rate of the left halfcolon cancer were all lower than of the right (P<0.05, their difference hasstatistical significance).5.With the different T staging, the rate of the lymph node metastasis inevery station,their difference has statistical significance(P<0.05),the lymphnode metastatic rate which was in the nearest pericolorectal nodal area wereall higher than around mesentery and in mesenteric roots.The lymph nodemetastatic rate of every station which lies in T4staging is higher than in T3staging and≤T2staging, their difference has statistical significance (P<0.05). Conclusion:1.MDCT can be used as an important means of examination to assess thelymph node metastatic of the colorectal cancer. As it has high consistencywith the post-operative pathology.2.The metastatic lymph node has a intendency of becoming bigger onesand larger quantities than the non-metastatic lymph node.3.The CT density value of the lymph node can be a key index ofassessing whether the lymph nodes transform or not.4.As to the anatomic distribution of the metastatic lymph node, there aresome regularities and characteristics. The dominant anatomic distribution ofthe metastatic lymph node was in the nearest pericolorectal nodal area;Whether in the nearest pericolorectal nodal area,around mesentery or inmesenteric roots,the lymph node rate of the left half colon cancer were alllower than of the right half colon cancer. The lymph node distribution has noregular pattern and advantage anatomic distribution for the non metastaticlymph node.5.With different T staging, the lymph node metastasis rate in the nearestpericolorectal nodal area was significantly higher than that of mesentery andmesenteric root. With T staging progressed,the lymph node metastatic rateincreased significantly and... |
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