Acorrelation Study Between Preoperative Staging Of Mri And Postoperative Pathology In Mid-low Rectal Cancer Based On "DISTANCE" Assessment Report

Object:To evaluate the accuracy of high-resolution MRI in preoperative T staging,N staging,CRM status,EMVI status,and the distance from the lower edge of the tumor to anal margin,based on the “DISTANCE” assessment report of the mid-low rectal cancer stage,and to explore the value of high-resolution MRI in preoperative staging of rectal cancer.Methods:We collected information of 83 pathologically confirmed mid-low rectal cancer patients from October 2016 to April 2017 in the Department of General Surgery,Affiliated Hospital of Qingdao University,including 61 males and 22 females,with an average age of 63.3 years.All patients underwent preoperative pelvic(rectal)high-resolution MRI dynamic contrast-enhanced scans by using a GE Signa HD 3.0T superconducting magnetic resonance scanner.Assess the T staging,N staging,CRM status,EMVI status,and distance from the lower edge of the tumor to anal margin on MRI data.All operations were performed according to the principle of total mesorectal excision(TME),of which 61 patients underwent Dixon surgery,20 patients underwent Miles surgery,2 patients underwent Hartmann surgery.Comparing the MRI evaluation results with the postoperative pathological results,the predictive value of MRI for T staging,N staging,CRM status,EMVI status,and the distance from the lower edge of the tumor to anal margin was obtained.Results:MRI correctly assessed T staging in 68 cases.The overall accuracy rate was81.9%(68/83).The accuracy,sensitivity,specificity,PPV,NPV of T1-2,T3 and T4 were evaluated.T1-2 stage was 86.7%,65.2%,95.0%,83.3%,87.7% respectively.Stage T3 was 84.3%,90.7%,72.4%,86.0%,80.8%,respectively.Stage T4 was 92.8%,66.7%,94.8%,50.0%,97.3%,respectively.Kappa test showed Kappa = 0.628,P = 0.000,indicating that the consistency of the two in determining the T staging of rectal cancer was good.MRI correctly assessed N staging in 53 cases.The overall accuracy rate of MRI was 63.9%(53/83).The accuracy,sensitivity,specificity,PPV,NPV of N0,N1,and N2 were evaluated.N0 stage were 75.9%,60.0%,94.7%,93.1%,66.7%,respectively.N1 stage were 74.7%,64.0%,53.4%,57.1%,56.4%,respectively.Stage N2 were 74.3%,76.9%,58.6%,38.5%,71.9%,respectively.The Kappa test showed Kappa=0.452,P=0.000,indicating that the two were moderately related.74 cases were assessed correctly by MRI in CRM.The accuracy of MRI evaluation was 89.2%,sensitivity was 80.0%,specificity was 91.2%,PPV was 66.7%,NPV was 95.4%.The kappa test showedkappa=0.660 P=0.000,and the consistency between the two results of the CRM state judgment was good.Comparing the preoperative MRI-EMVI evaluation and pathological results of 60 patients with pathologically confirmed rectal cancer greater than T3 stage,48 cases were assessed correctly by MRI.The accuracy of MRI evaluation was 80.0%,sensitivity was 53.3%,specificity was 88.9%,PPV was 61.5%,NPV was 85.1%.The Kappa test showed that Kappa=0.442 P=0.001,indicating that the two were moderately related.20 patients who underwent miles surgery were measured in the distance from the lower edge of the tumor to anal margin by both MRI and pathological results.Using paired sample t-test,the P value was greater than 0.05,indicating that MRI was similar to postoperative pathological measurements.Conclusion:High-resolution MRI has good accuracy in estimating preoperative T staging,CRM,and distance between the lower edge of the tumor and anal margin,and the accuracy of N-stage and EMVI estimates is moderate.This shows that high-resolution MRI has a higher diagnostic value for the comprehensive evaluation of mid-low rectal cancer preoperative staging.