磁共振酰胺质子转移成像与表观扩散系数在膀胱癌术前病理分级评估中的应用

Application of MR amide proton transfer imaging and apparent diffusion coefficient in preoperative pathological grade assessment of bladder cancer

目的研究酰胺质子转移(amide proton transfer,APT)成像与表观扩散系数(apparent diffusion coefficient,ADC)在膀胱癌术前组织学分级评估中的可行性。材料与方法回顾性分析了54例经手术病理证实为膀胱癌患者的影像资料,所有患者在术前接受了MRI检查。MRI扫描除常规序列外,另外包括APT及扩散加权成像(diffusion-weighted imaging,DWI)序列。由两位经验丰富的放射科医生独立测量病灶的APT及ADC值,采用独立样本t检验或Mann-Whitney U秩和检验比较不同级别肿瘤的各参数值之间的差异。然后采用受试者工作特征(receiver operating characteristic,ROC)曲线和DeLong检验分析APT、ADC及两者联合(APT+ADC)使用的诊断性能。结果低级别膀胱癌的APT值(1.42%±0.75%)低于高级别膀胱癌(2.99%±1.07%),差异具有统计学意义(P<0.01);低级别膀胱癌的ADC值[(1.44±0.27)×10^(-3)mm^(2)/s]高于高级别膀胱癌[(1.17±0.37)×10^(-3)mm^(2)/s],差异具有统计学意义(P=0.01)。APT值、ADC值及两者联合鉴别低级别膀胱癌和高级别膀胱癌的ROC曲线下面积(area under the curve,AUC)分别为0.80、0.76、0.94,ATP、ADC的AUC值与两者联合的AUC值之间差异具有统计学意义(P<0.05)。结论APT和ADC可作为膀胱癌术前预测组织学分级的指标,APT与ADC联合应用可显著提高诊断效能。

Objective:To study the feasibility of amide proton transfer(APT)imaging and apparent diffusion coefficient(ADC)in the preoperative histological grade assessment of bladder cancer.Materials and Methods:The imaging data of 54 cases of bladder cancer confirmed by surgery and pathology were retrospectively analyzed,all patients underwent magnetic resonance examination before surgery,and the scanning sequences included APT and diffusion-weighted imaging(DWI)functional sequences except for conventional sequences.APT and ADC values of tumors were measured by two experienced radiologists independently.An independent samples t-test or Mann-Whitney U-test was used to compare the differences in each parameter between different grades of tumors.The receiver operating characteristic(ROC)curves and DeLong test were used to evaluate the efficiency of APT,ADC and combined parameters.Results:The APT values for low-grade bladder cancer(1.42%±0.75%)were significantly lower than high-grade bladder cancer(2.99%±1.07%),with statistically significant differences(P<0.01);and the ADC values for low-grade bladder cancer were significantly higher[(1.44±0.27)×10^(-3) mm^(2)/s]than high-grade bladder cancer[(1.17±0.37)×10^(-3) mm^(2)/s],with statistically significant differences(P=0.01).The ROC curves showed that the area under the curve(AUC)of APT,ADC and the combined indicators for differentiating low-grade and high-grade bladder cancers were 0.80,0.76,0.94,and the AUC of combined parameters was significantly higher than that in APT or ADC(all P<0.05).Conclusions:APT and ADC can be used as indicators to predict the preoperative histological grades of bladder cancer,and the combination of APT and ADC can significantly improve the diagnostic efficacy.