Prospective Study On Staging And Grading Of Rectal Cancer Based On MR Multi-modal Scanning Technique

Objective : By MR multi-modal scanning technique(high resolution MRI,DWI and dynamic contrast-enhanced scan) in patients with rectal cancer,to explore the diagnostic value of the preoperative staging and grading of rectal cancer,to explore the predictive value of pathological T-staging and differentiation degree by ADC value for rectal carcinoma,to explore the application value of dynamic enhanced quantitative and semi quantitative parameters in predicting T-staging and differentiation degree of rectal cancer.Materials and methods: 51 cases of rectal cancer in Fuzhou General Hospital of Nanjing military region from April 2015 to February 2016 were selected.All patients underwent high resolution scanning and DWI(b=50,800, 1000s/mm2).50 cases underwent dynamic enhanced scan. Preoperative T-staging was respectively performed by HR-MRI, HR-MRI+enhanced scans, and then to calculate the ADC value, dynamic enhanced semi quantitative parameter value(peak, peak time, peak signal enhancement ratio) and dynamic enhanced quantitative parameter value(Ktrans,Ve, Kep, i AUC) of ROI.Statistical methods:The accuracy,sensitivity,specificity, positive predictive value and negative predictive value of the preoperative staging of rectal cancer were calculated separately by using high resolution MRI and high resolution MRI+enhanced scans. Using Kappa-test to analyze the consistency of preoperative radiological staging and postoperative pathological staging;Using one-way analysis of variance to compare the differences of ADC value, dynamicquantitative and semi quantitative parameter values between different pathological T stages/pathological differentiation degrees;P<0.05 that difference was statistically significant.Results:1. The accuracy, sensitivity, specificity, PPV and NPV by alone using high resolution MRI in rectal cancer:(≤T2)92.50%, 90.91%, 93.10%, 83.33% and96.43%;(T3) 75.00%, 73.33%, 76.00%, 64.71% and 82.61%;(T4) 82.50%,64.29%,92.31%,81.82% and 82.76%. The accuracy, sensitivity, specificity, PPV and NPV by using high resolution MRI and enhancement scanning in rectal cancer:(≤T2)94.87%,100.00%, 92.86%, 84.60% and 100.00%;(T3)76.92%, 71.43%, 80.00%, 66.67% and83.33%;(T4) 76.92%, 57.14%, 88.00%, 72.73% and 78.57%. 2. Whenever b=800 or1000s/mm2, the differences of ADC value between different degrees of differentiation of rectal cancer were significant(P=0.019,0.001), and the lower the degree of differentiation, the lower the average ADC value, and there was no significant difference in the ADC value between different pathological T stages. 3. There was significant difference in the Ve value between different degree of pathological differentiation of rectal cancer(P=0.044), and the lower the degree of differentiation,the higher the average Ve value;the rest of the dynamic enhancement parameters of rectal cancer were not statistically significant.The differences between the dynamic enhanced quantitative and semi quantitative parameters of different pathological T-staging in rectal cancer were not statistically significant.Conclusion: High resolution MRI has important diagnostic value for T staging of rectal cancer,combining with enhanced scan can improve the diagnostic performance. ADC value and Ve value can predict the degree of differentiation of rectal cancer to a certain degree.The combined application of multi-modal MR scanning technique has good application value in preoperative staging and grading of rectal cancer.