单指数、双指数模型多b值DWI在胰腺癌的应用价值

目的 探讨单指数、体素内不相干运动成像(IVIM)双指数模型多b值扩散加权成像(DWI)定量参数在胰腺癌的应用价值.方法 应用3.0T磁共振扫描仪对临床或手术证实的37例胰腺癌患者行胰腺多b值DWI.应用单指数、IVIM双指数模型分析多b值DWI,测量胰腺癌和癌周胰腺组织的标准化表观扩散系数(ADCstandard)、纯扩散系数 (ADCslow)、假扩散系数(ADCfast) 和灌注分数(f),并应用独立样本t检验进行统计学分析.结果 胰腺癌的ADCslow值高于癌周胰腺组织的ADCslow值(0.611×10-3 mm2/s vs 0.521×10-3 mm2/s,P=0.037),而胰腺癌的ADCfast和f值低于癌周胰腺组织的ADCfast和f值(5.066×10-3 mm2/s vs 7.188×10-3 mm2/s,P=0.035;55.8% vs 64.0%,P=0.016),差异均有统计学意义.胰腺癌的ADCstandard值和ADCslow值显著正相关(r =0.824,P=0.000);ADCfast值和f值显著负相关(r=-0.558,P=0.000).结论 IVIM-DWI的灌注相关参数(ADCfast、f)和扩散相关参数(ADCslow)可以有效鉴别胰腺癌和癌周胰腺组织,IVIM-DWI是无创性早期诊断和鉴别胰腺癌与癌周胰腺组织的理想方法之一.

The application value of monoexponential,biexponential models multiple b values DWI in pancreatic cancer

Objective To explore the application value of monoexponential, biexponential models multiple b values diffusion weighted imaging(DWI) in distinguishing pancreatic cancer from non-tumorous pancreas.Methods Subjects comprised 37 pancreatic cancers confirmed by clinical or surgery.Pancreas multiple b values DWI was performed using 3.0T scanner.Standard apparent diffusion coefficient (ADCstandard) was calculated using monoexponential diffusion model.Pure diffusion coefficient (ADCslow), pseudodiffusion coefficient (ADCfast) and perfusion fraction (f) were calculated using intravoxel incoherent motion(IVIM) diffusion model.Parameters of pancreatic cancers and non-tumorous pancreas were compared using independent samples t test.Results Mean ADCslow value of pancreatic cancer was higher than that of non-tumorous pancreas (0.611×10-3 mm2/s vs 0.521×10-3 mm2/s,P=0.037).Mean ADCfast and f values of pancreatic cancer were lower than that of non-tumorous pancreas (5.066×10-3 mm2/s vs 7.188×10-3 mm2/s,P=0.035;55.8% vs 64.0%,P=0.016;respectively).ADCslow of pancreatic cancer was positively correlated to ADCstandard (r=0.824,P=0.000).ADCfast of pancreatic cancer was negatively correlated to f(r=-0.558,P=0.000).Conclusion ADCslow, ADCfast and f derived from IVIM-DWI model can distinguish pancreatic cancer from non-tumorous pancreas.IVIM-DWI may be a promising and non-invasive tool for early diagnosing and differentiating pancreatic carcinoma from non-tumorous pancreas.