The Diagnostic Value Of Three-dimensional Endorectal Ultrasound And Magnetic Resonance Imaging In The Evaluation Of Mesorectal Fascia In Middle And Low Rectal Cancer

Background:Rectal cancer refers to a malignant tumor that occurs in the intestine and is within 15 cm from the edge of the anus.Its morbidity and mortality are increasing year by year.The main treatment methods for rectal cancer include surgical resection,chemotherapy and radiation therapy.Total mesorectal excision(Total Mesorectal Excision,TME)is currently one of the most recognized and widely used rectal cancer procedures.Circumferential Resection Margin(CRM)of rectal cancer is the most recognized single index for predicting local recurrence.In rectal cancer,CRM-negative surgical resection is crucial.The status of Mesorectal Fascia(MRF)before surgical resection is closely related to the CRM after surgical resection.Before rectal cancer surgery,it is important to predict the CRM status by evaluating the MRF status.It is used for imaging examination of rectal cancer staging,lymph node staging,and MRF status,including magnetic resonance imaging(Magnetic Resonance Imaging,MRI)and endorectal ultrasound(ERUS).Among them,high-resolution thin-layer MRI is currently the preferred imaging method for partial stage and MRF status assessment of bowel cancer.Three Dimensional Endorectal Ultrasound(3D-ERUS)is an imaging method used in preoperative MRF assessment of rectal cancer in recent years.Studies have shown that 3D-ERUS has important clinical value in rectal cancer staging,lymph node staging,and MRF status assessment.The clinical value of 3D-ERUS and MRI in MRF is the focus of research in recent years.Although some studies believe that the clinical value of 3D-ERUS and MRI in MRF evaluation is very high,many studies have not excluded patients with preoperative radiotherapy and chemotherapy,and there is a lack of research on the correlation analysis and diagnostic value of the two examinations.In addition,multiple studies have shown that radiochemotherapy may reduce the accuracy of imaging assessment of MRF.Purposes:Taking postoperative pathology as the gold standard,analysis of MRI and 3D-ERUS was used to evaluate the correlation and diagnostic value of MRF involving non-radiotherapy and low rectal cancer.Methods:Part 1 Correlation analysis between 3D-ERUS and MRI in MRF assessmentMethods: A total of 51 patients with low and middle rectal cancer diagnosed without radiotherapy and chemotherapy in our hospital from January 2018 to April 2020 were screened.All enrolled patients underwent pre-operative three-dimensional endorectal ultrasound examination and MRI examination in our hospital,and can obtain complete imaging data.Trans-rectal ultrasound equipment used PRO Focus 2202(BK Medical,Peabody)ultrasound scanner.MRI uses(Ingenia;Philips Healthcare,Andover)scanner.Record the patient’s age,height,weight,and body mass index(BMI)before surgery;the researchers measured and recorded the T stage,intestinal lymph node,and tumor distance of the tumor by 3D-ERUS and MRI before the patient underwent surgery.The distance of the anal margin(unit: cm),the orientation of the intestinal wall(recorded at 12 o’clock),and the shortest distance between the deepest part of the tumor and the MRF(unit: mm).The researchers independently measured and blinded each other’s measurement results.Double quantitative normal distribution data,using Pearson correlation coefficient to analyze the correlation between MRI and 3D-ERUS.P <0.05 was considered statistically significant.Part 2 The diagnostic value of 3D-ERUS and MRI in MRF evaluationMethods: A total of 41 patients with low and medium rectal cancer diagnosed in our hospital from January 2018 to April 2020 without radiotherapy and chemotherapy were screened.All enrolled patients underwent pre-operative transrectal three-dimensional ultrasound examination and MRI examination in our hospital,and can obtain complete imaging data,surgical data and pathological examination results.Surgical treatment within one week after imaging examination.Record general information about the patient,including age,height,weight,gender,and BMI.The items to be observed and recorded by MRI and 3D-ERUS include tumor location,morphology,size,boundary,range,distance from the anal verge(cm),tumor T stage,intestinal lymph nodes,and MRF qualitative diagnosis results.After rectal cancer surgery,record the pathological results of all patients,including pathological TNM staging and CRM qualitative diagnosis results.Taking postoperative pathology as the gold standard,the diagnostic value of 3D-ERUS and MRI in MRF evaluation was compared and analyzed.P <0.05 was considered statistically significant.Results:1.A total of 51 patients were enrolled,with an average age of(61.812.5)years,including 23 males and 28 females,34 patients with median rectal cancer(tumor 5.1-10 cm from the anal margin),and low rectal cancer(tumor 17 cases from the anal edge ≤5cm).The Pearson correlation coefficient r of the measured distance between 3D-ERUS and MRI is 0.960(P <0.001).2.A total of 41 patients with middle and low rectal cancer without radiotherapy and chemotherapy were included,including 27 patients with median rectal cancer(tumor 5.1-10 cm from the anal margin)and 14 patients with low rectal cancer(tumor ≤5.0cm from the anal margin).The average age of patients was(61.212.9)years old,including 19 male patients and 22 female patients.In the consistency analysis,the kappa value of 3D-ERUS and pathology was 0.627(P <0.001);the kappa value of MRI and pathology was 0.600(P <0.001).The accuracy of 3D-ERUS diagnosis of low and middle rectal cancer without radiotherapy and chemotherapy was 85.4%,sensitivity was 72.7%,specificity was 90.0%,positive predictive value was 72.7%,negative predictive value was 90.0%,and Yoden index was 62.7%.The accuracy of MRI diagnosis of low and middle rectal cancer without radiotherapy and chemotherapy was 82.9%,sensitivity was 81.8%,specificity was 83.3%,positive predictive value was 64.3%,negative predictive value was 92.6%,and Yoden index was 65.1%.In the paired chi-square test,the P value of 3D-ERUS and MRI was> 0.05.The kappa value of 3D-ERUS and MRI was 0.600(P <0.001)Conclusions:There is a strong correlation between 3D-ERUS and MRI in the evaluation of MRF involving non-radiochemotherapy of low and middle rectal cancer.The application of 3D-ERUS and MRI in the evaluation of MRF involving non-radiochemotherapy of low and middle rectal cancer has good diagnostic value and good consistency.In the diagnosis of rectal cancer involving MRF,3D-ERUS may have clinical application prospects complementary to MRI.