Clinical Value Of VI-RADS And Qualitative And Quantitative Indexes In Multi-parameter Magnetic Resonance Imaging In Predicting Muscle Invasion Of Bladder Cancer

Objective: The purpose of this study is to verify the diagnostic efficacy of VI-RADS for muscle invasion of bladder cancer,and to study whether the maximum diameter of tumor,the length of tumor-wall interface,ADC value and the morphology of tumor stalk can be used as qualitative or quantitative indexes to predict the muscle invasion in bladder cancer.Methods: The imaging and pathological data of patients with bladder MRI 3.0T plain scan plus enhanced scan from August 2017 to July 2021 were collected retrospectively.The maximum diameter of the tumor,the length of tumor-wall interface,were measured by a urologist on T2 WI and DWI images respectively for three times,and the average value was taken.The ratio of the maximum diameter of the tumor to the length of tumor-wall interface was calculated directly.The morphology of tumor stalk was evaluated directly from the DWI image,ADC value can be obtained directly.The VI-RADS was scored separately and independently by two urologists with different seniority,the interobserver agreement was assessed by the Kappa test.According to the postoperative pathology,the patients were divided into two groups: muscular invasive bladder cancer and non-muscular invasive bladder cancer.The statistical methods were selected according to the data characteristics,and used to evaluate whether there was statistical difference between the two groups.The meaningful tumor characteristics were further analyzed,their receiver operating characteristic curve was drawn,the area under the curve was calculated,and the cut off value,sensitivity and specificity were calculated by Yoden index.Results: Among the 83 patients included in the study,there were 21(25.3%)patients with MIBC and 62(74.7%)patients with NIMBC.The Kappa value of the two urologists in VI-RADS score is0.819,which is in great agreement.There were significant differences in tumor maximum diameter,the length of tumor-wall interface,ADC value and VI-RADS between the two groups(p<0.000).There were also significant differences in the ratio of tumor maximum diameter to the length of tumor-wall interface between the two groups(p<0.001).Under each MRI sequence image,the AUC,cut off value,sensitivity and specificity of various tumor features are as follows: the maximum diameter of the tumor is 0.840-0.845,2.959-3.052 cm,0.762-0.857,0.742-0.774,and the length of tumor-wall interface is 0.876-0.879,3.052-3.660 cm,0.762-0.810,0.774-0.855.The ratio of the maximum diameter of the tumor to the length of tumor-wall interface was 0.769-0.810,0.967-0.982,0.810,0.661,and the ADC values of the tumor were 0.893,1050.5,0.911 and 0.722,respectively.The VI-RADS were 0.923-0.924,4,0.762 and 0.984.The sensitivity,specificity and accuracy of central tumor stalk to NMIBC were 0.651,0.905 and 0.723,respectively.Conclusion: VI-RADS is effective in the diagnosis of muscle invasion of bladder cancer,and the diagnostic efficacy of 4 points is the best.Tumor maximum diameter,the length of tumor-wall interface,ADC value and tumor stalk morphology all have predictive significance for muscle invasion.The ratio of tumor maximum diameter to the length of tumor-wall interface is newly introduced,which can be used to evaluate again when the two conclusions are contradictory.