Qualitative And Quantitative Assessment Of Extracapsular Extension In Prostate Cancer By Multiparametric MRI

Objective:In this study,we were aim to assess the value of multiparametric magnetic resonance imaging（mpMRI）in the diagnosis of extracapsular extension（ECE）in prostate cancer（PCa）from two aspects of morphological characteristics and functional information,thus providing a reliable diagnostic basis for clinical work.Methods:A total of 59 patients with prostate cancer diagnosed in our hospital from June 2017 to December 2018 were enrolled in our study.All patients underwent multi-parameter（T₁WI,T₂WI,DWI and DCE-MRI）magnetic resonance examination before surgery.All patients underwent radical prostatectomy and were confirmed by postoperative pathology as prostate cancer.According to the second edition of the Prostate Imaging Reporting and Data System（PI-RADS V2）,the acquired images were analyzed by two readers respectively and compared with pathological results.Using pathological results as the gold standard,the diagnostic method was used to calculate the sensitivity,specificity and accuracy of T₂WI,DWI,DCE,T₂WI+DWI,T₂WI+DCE and T₂WI+DWI+DCE in the diagnosis of extracapsular extension（ECE）of prostate cancer.The paired chi-square test was applied to compare the accuracy of different parameters and their combination to diagnose ECE of prostate cancer.The obtained images were input into the corresponding software,and the ADC,K^trans,K_ep,and V_e values of each tumor were calculated and analyzed.The independent sample t test was used to compare the extracapsular extension group（ECE+）and the non-extracapsular extension group（ECE-）.The binary logistic regression analysis was used to study the diagnostic efficiency of the combination of ADC and Ktrans value for ECE of prostate cancer.Differences in the values of the parameters were applied to draw the receiver operating characteristic curve（ROC curve）to analyze the efficiency of each parameter and its combination to diagnose the ECE in prostate cancer.Kappa consistency test was used to evaluate the consistency of ECE and pathological results in multi-parameter MRI diagnosis and the consistency of two readers.Results:1.The sensitivity,specificity and accuracy of T₂WI,DWI,DCE,T₂WI+DWI,T₂WI+DCE and T₂WI+DWI+DCE for ECE diagnosis of prostate cancer were:68.0%,55.9%,61.0%,64.0.%,52.9%,57.6%,68.0%,41.2%,52.5%,80.0%,85.3%,83.1%,80.0%,82.4%,81.4%,88.0%,85.3%,86.4%.The specificity and accuracy of T₂WI+DWI+DCE in the diagnosis of prostate cancer were significant higher than those in T₂WI,DWI and DCE-MRI alone（P<0.05）.Multi-parametric MRI diagnosis of prostate cancer ECE was consistent with pathological findings,Kappa=0.754,and the two readers analyzed image data were basically consistent,Kappa=0.737.2.There was a statistically significant difference of apparent diffusion coefficient（ADC value）and DCE-MRI quantitative parameters（Volumetric transport constant,Ktrans and rate constant,Kep）between the two groups:（ECE+）and（ECE-）（P<0.05）.There was no significant difference in the extravascular space volume（Ve）between the two groups;the area under the ROC curve（AUC）for each parameter was:ADC（0.864）,Ktrans（0.866）,Kep（0.768）,Ve（0.601）.The AUC value of combined ADC and Ktrans was 0.921,which was higher than qualitative T2WI+DWI+DCE.When the boundary value was 0.325,the sensitivity and specificity were 96%and 82.4%,respectively,which was higher than ADC and Ktrans values alone.Conclusions:1.Combined T₂WI and DWI and DCE can improve the specificity and accuracy of extracapsular extension in prostate cancer,and provide an important diagnostic basis for preoperative clinical staging of prostate cancer.2,ADC value and quantitative DCE-MRI parameters K^trans,K_ep has the potential to assess the extracapsular extension in prostate cancer.Combining the ADC with the Ktrans value greatly improves the effectiveness of the diagnostic ECE,contributing to the preoperative clinical stage of prostate cancer,the development of prostate cancer treatment plan and prognosis important.