The Application Value Of High-resolution MRI T2WI Combined With IVIM-DWI In Preoperative Staging Of Rectal Adenocarcinoma

Objective:To investigate the application value of high-resolution MRI T2WI(HR-T2WI)combined with intranoved incoherent motion diffusion weighted imaging(IVIM-DWI)in preoperative staging of rectal adenocarcinoma,to evaluate the physiological changes and invasiveness of the tumor tissue,and to provide guidance for the selection of the best clinical treatment options.Materials and methods:1.A total of 47 cases of rectal adenocarcinoma patients who received surgery for rectal adenocarcinoma in gastrointestinal and breast surgery department of our hospital from October 2017to February 2019 without preoperative radiotherapy and chemotherapy were diagnosed as rectal adenocarcinoma by postoperative pathology.There were 34 males and 13 females.According to the treatment and prognosis evaluation of rectal cancer,the most important thing was whether the tumor breaks through the muscular layer of the intestinal wall and the identification principle of lymph node metastasis.In this study,the T stage was divided into the unbreakable group(T1-2)and the breakthrough group(T3-4),N stage was divided into N0 group and N+group.2.All patients underwent GE 3.0T MRI HR-T2WI and IVIM-DWI scan before surgery.Those images were post-processed by Functool-MADC software to obtain the pseudo diffusion coefficient(D*)value,the true diffusion coefficient(D)value,and the perfusion fraction(f)value.These values were measured in the parenchymal portion of the tumor by avoiding significant vascular,cystic,hemorrhagic and necrotic areas by multiple b-value IVIM-DWI double exponential decay models.The apparent diffusion coefficient(ADC)value was obtained by DWI single-index model.And the preoperative MRI staging of patients with rectal adenocarcinoma was compared with postoperative pathological results.3.All data were statistically analyzed using SPSS 21.0 statistical software.The measurement data were expressed as mean±standard deviation(±S),and the comparison between groups was tested.The diagnostic value of IVIM-DWI for T staging and N staging was further evaluated by a single factor analysis of P<0.05.The classification and count data were compared using the paired?~2 test.Kappa consistency test was used to compare the HR-T2WI and its combined IVIM-DWI images to diagnose the consistency of preoperative staging and postoperative pathological findings.The test level?=0.05,P<0.05 was considered statistically significant.Results:1.The coincidence rate of T-stage diagnosis of rectal adenocarcinoma with HR-T2WI was 82.98%(39/47);2.D value and ADC value gradually decreased with the deepening of rectal adenocarcinoma tumor infiltration depth,the difference was statistically significant(P<0.05);D*value and f value were different between different rectal adenocarcinoma tumor infiltration depth,there was no statistical significance(P>0.05).The area under the curve(AUC)of the D value and the ADC value in the diagnosis of the unbreakable group were 0.801 and 0.713.The difference was statistically significant(P<0.05)and the diagnostic value of the D value was higher;In the N staging of rectal adenocarcinoma,the D value of lymph nodes in the N+group tended to be lower than that in the N0 group,and the difference between them was statistically significant(P<0.05).The AUC of D value in the diagnosis of non-metastatic lymph nodes was 0.799,which was of high diagnostic value(P<0.05).However,there was no statistical difference in the D*value,the f value,and the ADC value between the N-stage groups;3.The coincidence rate of the T-stage diagnosis of rectal adenocarcinoma with HR-T2WI combined with IVIM-DWI was 87.23%(41/47).Conclusion:1.HR-T2WI can better evaluate the preoperative staging of rectal adenocarcinoma from an anatomical level;2.The quantitative parameters of IVIM-DWI can supplement the preoperative T-stage of rectal adenocarcinoma to a certain extent.ADC value and D value can better diagnose the T-stage of rectal adenocarcinoma.The effect of D value on the removal of capillary perfusion effect After that,the D value has a higher diagnostic value;D value has a good diagnostic value in identifying the benign and malignant lymph nodes;3.HR-T2WI combined with IVIM-DWI has a certain value in the accuracy of preoperative staging of rectal adenocarcinoma.