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目的 探讨拉伸指数与单指数模型多b值磁共振扩散加权成像(DWI)定量参数在胰腺癌的应用价值.方法 搜集临床或手术证实的37例胰腺癌患者,应用GE Discovery MR750 3.0T磁共振扫描仪对所有患者行胰腺多b值DWI.应用MADC软件的单指数和拉伸指数模型分析多b值DWI,得到标准化表观扩散系数(ADCstandard)、分布扩散系数(DDC)和扩散异质性指数(α)参数图,测量胰腺癌和癌周胰腺组织的ADCstandard、DDC和α值,并应用独立样本t检验进行统计学分析.结果 胰腺癌的DDC值明显低于癌周胰腺组织的DDC值(1.244×10-3mm2/sVs.1.679×10-3mm2/s,P=0.013),胰腺癌的α值明显高于癌周胰腺组织的α值(0.720 vs.0.653,P=0.019),差异均有统计学意义.DDC和α值鉴别胰腺癌和癌周胰腺组织的受试者工作特征曲线(ROC)曲线下面积分别为0.640、0.631.胰腺癌的DDC值和ADCstandard值显著正相关(r=0.401,P=0.013);α值和ADCstandard值显著正相关(r =0.360,P=0.026).结论 拉伸指数模型DWI相关参数DDC和α可以鉴别胰腺癌和癌周胰腺组织,DDC鉴别胰腺癌和癌周胰腺组织时较α的诊断效能更高.“,”Objective To explore the application value of quantitative parameters derived from monoexponential and stretched-exponential models (SEM) multiple b values diffusion weighted imaging in distinguishing pancreatic cancer from non-tumorous pancreas.Methods Subjects comprised 37 pancreatic cancers confirmed by clinical data or surgery.Pancreas multiple b values DWI were performed using GE Discovery MR750 3.0T scanner.Standard apparent diffusion coefficient (ADCstandard) was calculated using monoexponential diffusion model.Distributed diffusion coefficient (DDC) and diffusion heterogeneity index (α) were calculated using SEM diffusion model.ADCstandard,DDC and α value of pancreatic cancers and non-tumorous pancreas were compared using Independent Samples t-Test.P values ＜ 0.05 were considered significant.Results Mean DDC value of pancreatic cancer was significantly lower than that of non-tumorous pancreas (1.244 vs.1.679 × 10-3mm2/s,P =0.013).Mean α value of pancreatic cancer was significantly higher than that of nontumorous pancreas (0.720 vs.0.653,P =0.019).Areas under the curve (AUC) for DDC and α were 0.640 and 0.631 respectively.The diagnostic performance of DDC in differentiating pancreatic cancer from non-tumorous pancreas was higher than α.DDC of pancreatic cancer was positively correlated to ADCstandard (r =0.401,P =0.013).α of pancreatic cancer was positively correlated to ADCstandard (r =0.360,P =0.026).Conclusion DDC and α derived from SEM DWI model can distinguish pancreatic cancer from non-tumorous pancreas.DDC is the better parameter than α for differentiating pancreatic cancer from non-tumorous pancreas.