Multimodal MRI Evaluation Of Preoperative T Staging/differentiation Of Rectal Cancer

Objective: The purpose of this study was to evaluate the value of magnetic resonance imaging(MRI)in the preoperative diagnosis of rectal cancer by comparing the postoperative pathology with high-resolution MRI,diffusion-weighted imaging and dynamicenhanced imaging.Materials and Methods: A retrospective analysis was performed on 79 cases of rectal cancer patients who were pathologically diagnosed and staging after menstruation surgery in The 900 th hospital of Joint Logistics Support Force from August 2018 to February 2019.All of the patients on the basis of routine MRI scan sequence T1 WI,T2WI,shaft,crown,three plane vector high-resolution MRI scans(HR-MRI),diffusion weighted imaging(DWI)and dynamic enhanced scan(DCE).T staging base on HR and DCE,the calculation is based on the ADC figure of the DWI after disposal can automatically generate ADC values focal areas of interest,through to the target of continuous rapid sampling signal and draw the time signal intensity curve(time-intensity curve,TIC),type of TIC analysis of rectal cancer,measuring the tumor time to peak(TTP),signal peak(SP)and signal enhancement ratio(ER),and analyze them comprehensively.The image T staging of HR-MRI,DCE-MRI,and HR+DCE-MRI were compared with pathological T staging,respectively,and the accuracy,sensitivity,specificity,positive predictive value,and negative predictive value of image diagnosis were obtained.Kappa test was used to analyze the consistency between preoperative imaging staging and postoperative pathological staging.Univariate anova of factorial design data was used to compare the differences of ADC values and semi-quantitative parameters of pathological T staging/differentiation of rectal cancer.P < 0.05 was considered statistically significant.Results: 1.Postoperative pathological T staging of 79 patients: 21 cases in stage T1-2,48 cases in stage T3,and 10 cases in stage T4;Differentiation degree: 15 cases had low pathological differentiation,56 cases had medium pathological differentiation,and 8 cases had high pathological differentiation.There were 21 cases in the upper segment,25 cases in the middle,and 33 cases in the lower.2.The diagnostic value of HR-MRI for preoperative staging of rectal cancer was as follows: accuracy,sensitivity,specificity,positive predictive value and negative predictive value were(T1~2 stage)87.34%,76.19%,91.38,76.19%,91.38%,(T3 stage)82.28%,83.33%,80.65%,86.96%,75.76%,(T4 stage)94.94%,90.00%,96.65%,75.00%,98.51%,respectively.The diagnostic value of DCE for preoperative staging of rectal cancer was as follows: accuracy,sensitivity,specificity,positive predictive value and negative predictive value were(T1~2 stage)82.28%,71.43%,86.21%,65.22%,89.29%,(T3 stage)78.48%,81.25%,74.19%,82.98%,71.88%,(T4 stage)96.20%,80.00%,98.55%,88.89%,97.14%,respectively.The diagnostic value of HR combined with DCE for preoperative staging of rectal cancer was as follows: accuracy,sensitivity,specificity,positive predictive value and negative predictive value were(T1~2 stage)93.67%,85.71%,96.55%,90.00%,94.92%,(T3 stage)92.41%,93.75%,90.32%,93.75%,90.32%,(T4 stage)98.73%,100.00%,98.55%,90.91%,100.00%,respectively.3.There was a statistical difference between different differentiation degrees of rectal cancer and ADC values(P < 0.05).The later the stage was,the deeper the tumor invasion was,and the lower the ADC was,but the difference was not statistically significant.4.The dynamic curve of rectal cancer in functional imaging showed as fast-rising-platform/slow falling-or fast-rising-rapid-slow falling-type;As the stage increased,the tumor infiltration degree deepened,the TTP showed a shortening trend,and there was no difference between SP and ER.The lower the differentiation,the higher the malignancy,the shorter the TTP,and the higher the trend of SP and ER.Although the difference was not statistically significant,it had predictive value for differentiation.Conclusion:(1)HR-MRI is one of the main diagnostic methods for preoperative T staging of rectal cancer in the multimode MR method,and the combination of DCE can improve the accuracy of preoperative staging.(2)DWI can more clearly highlight the tumor contour in the morphology of rectal cancer,and ADC can evaluate the degree of malignancy of rectal cancer from the molecular level.(3)The walking of dynamic curve is helpful for the diagnosis of rectal cancer,and TTP has certain predictive value in the staging/differentiation of rectal cancer,which can provide guidance for clinical surgery.(4)The comprehensive evaluation of multi-mode MRI scan on the T staging/differentiation of rectal cancer can provide abundant information and reliable guidance value for preoperative clinical practice.