Application Value Of 3.0T MRI To Evaluate The Efficacy Of Neoadjuvant Chemoradiotherapy For Rectal Cancer

ObjectiveTo explore the application value of 3.0T magnetic resonance in patients with rectal cancer after receiving neoadjuvant chemoradiotherapy,and to provide a preoperative reference for surgery.MethodsA total of 70 pathologically confirmed rectal cancer patients admitted to our hospital from January 2017 to December 2022 were retrospectively collected,and all of them received neoadjuvant chemoradiotherapy before surgery.Before neoadjuvant chemoradiotherapy,all patients underwent enhanced 3.0T MRI to record tumor T,N stage and circumferential resection margin,and after neoadjuvant chemoradiotherapy,MRI images were collected after the 4 weeks end of treatment,compared with T,N stages and circumferential resection margin before neoadjuvant chemoradiotherapy.Two imaging experts with more than ten years of experience in the imaging diagnosis were independently blinded to evaluate the MRI images by T,N staging and circumferential resection margin involvement,and if there was any disagreement,a third expert was asked to assist,and the final evaluation results corresponded to the pathological data of the patients and statistically analyzed.The Kappa conformance test was used to statistically analyze the results of the evaluation of T,N stage and circumferential resection margin involvement in the two physicians.Wilcoxon’s symbol rank sum test was used to evaluate the changes of T and N stages before and after neoadjuvant chemoradiotherapy in patients with rectal cancer before surgery,χ~2 test to evaluate circumferential resection margin involvement before and after neoadjuvant chemoradiotherapy,and the T stage,N stage and circumferential resection margin involvement recorded after treatment were compared with the pathological conclusions.The Kappa conformance test was used to analyze the application value of 3.0T MRI in evaluating the efficacy of neoadjuvant chemoradiotherapy for rectal cancer.ResultsThe two physicians agreed well in the assessment of T,N stage and circumferential resection margin involvement(Kappa=0.807,0.784,0.858).The3.0T MRI scan after neoadjuvant chemoradiotherapy showed that the T stage was statistically significant compared with before neoadjuvant chemoradiotherapy(Z=6.335,P<0.05),and the N stage was statistically significant compared with before neoadjuvant chemoradiotherapy(Z=5.786,P<0.05),and circumferential resection margin was not statistically significant compared with before neoadjuvant chemoradiotherapy(χ~2=1.067,P>0.05).The MRI T stage after neoadjuvant chemoradiotherapy was in good agreement with the postoperative pathological results(Kappa=0.675),and the accuracy rate was 75.7%(53/70).Circumferential resection margin was consistent with the postoperative pathological results(Kappa=0.759),and the accuracy rate was90.0%(63/70).N stage was poorly consistent with postoperative pathological results(Kappa=0.204),and its accuracy was 58.57%(41/70).Conclusions1.neoadjuvant chemoradiotherapy improved tumor T and N stages compared with before neoadjuvant chemoradiotherapy.neoadjuvant chemoradiotherapy could reduce tumour stage,but circumferential resection margin involvement could not be significantly improved.2.3.0T MRI scan to detect T stage and circumferential resection margin after neoadjuvant chemoradiotherapy had good consistency with postoperative pathological results,which could accurately evaluate the degree of tumor invasion,but the assessment of lymph node metastasis was relatively poor.