MR体素内不相干运动成像评价膀胱尿路上皮癌病理分级及肌层侵犯

Intravoxel incoherent motion MRI for prediction of histological grade and muscle invasion in bladder urothelial carcinoma

目的探讨MR体素内不相干运动成像(IVIM)在膀胱尿路上皮癌病理分级及肌层侵犯中的应用价值。方法将60例经手术及病理证实的膀胱尿路上皮癌患者分为低级别(LG)和高级别(HG)组、非肌层侵犯(NMIBC)和肌层侵犯(MIBC)组。比较组间IVIM参数[表观弥散系数标准值(ADC_(st))、慢扩散系数(D)、灌注分数(f)和快扩散系数(D*),建立二元Logistic回归模型,计算IVIM参数两两组合的预测概率值;绘制IVIM参数及其组合预测概率值的ROC曲线,并评价其诊断效能。结果HG组ADC_(st)、D和f值低于LG组(P均<0.05),其ROC曲线下面积(AUC)分别为0.88、0.86、0.72(P均<0.01);ADC_(st)和D、ADC_(st)和f、D和f组合预测概率值的AUC分别为0.91、0.90和0.88(P均<0.000 1)。MIBC组ADC_(st)、D和f值低于NMIBC组(P均<0.000 1),其AUC分别为0.91、0.85和0.88(P均<0.000 1);ADC_(st)和D、ADC_(st)和f、D和f组合预测概率值的AUC值均为0.93(P均<0.000 1)。结论 ADC_(st)、D和f值越低,提示膀胱尿路上皮癌病理分级越高,侵犯肌层可能性越大;IVIM多参数组合可提高诊断效能。

Objective To observe the utility value of MR intravoxel incoherent motion （IVIM） in histological grading and muscle invasion of bladder urothelial carcinoma. Methods According to postoperative histologic grade and T staging, 60 patients with bladder urothelial carcinoma confirmed by surgery and pathology were divided into low grade （LG） group and high grade （HG） group, as well as muscle-noninvasive bladder cancer （NMIBC） or muscle-invasive bladder cancer （MIBC） group. MR IVIM parameters （apparent diffusion coefficient standard [-ADCst], true diffusion coefficient [D], pseudodiffusion coefficient [D] and perfusion fraction [f]） were compared with independent-samples t tests. A binary Logistic regression model was established to evaluate the predicted probability of combined IVIM parameters. ROC curves of IVIM parameters and their combination＇s predicted probability were drawn, and the diagnostic efficiency was evaluated. Results ADCst, D and f values of HG group were significantly lower than those of LG group （all P〈0.05）. Area under ROC curve （AUCs） for ADCst, D and f value to differentiate HG from LG were 0.88, 0.86 and 0.72, respectively （all P〈0.01）, and AUCs for predicted probability of combined ADCst and D, combined ADCst and f and combined D and f were 0. 91, 0. 90 and 0. 88, respectively （all P〈O. 000 1）. ADCst, D and f values of MIBC group were significantly lower than those of NMIBC group （all P〈0. 000 1）. AUCs for ADCst, D and f value to differentiate MIBC from NMIBC were 0.91, 0.85 and 0.88, respectively （all P%0. 000 1）, and all AUCs for predicted probability of combined ADCs, and D, combined ADCst and f and combined D and f were both 0.93 （all P〈0. 000 1）. Conclusion Lower ADCst, D and f values may indicate greater possibility of high grade and muscle invasion of bladder urothelial carcinoma. Combination of IVIM parameters can improve diagnostic efficacy.