目的：探讨磁共振体素内不相干运动扩散加权成像（introvoxel incoherent motion diffusion weighted ima-ging,IVIM-DWI）不同参数诊断活动期克罗恩病的价值及效能。方法：收集30例经内镜确诊的活动期克罗恩病患者患病肠壁作为克罗恩病组,以同层面正常肠壁作为对照组。所有受试者均行MRI平扫和IVIM-DWI检查,测算肠壁表观扩散系数（apparent diffusion coefficient, ADC）值、真性水分子扩散系数（D）、微循环灌注系数（D*）和灌注分数（f）值。克罗恩病组与对照组各参数的比较采用独立样本t检验,采用受试者操作特征曲线（receiver operator characteri-stic curve, ROC曲线）评估IVIM各参数诊断活动期克罗恩病的效能。结果：克罗恩病组的IVIM参数ADC值、D*值及f值均低于对照组,差异有统计学意义（P<0.05）;2组间的D值差异无统计学意义（P>0.05）。IVIM相关参数ADC值、D*值、f值诊断活动期克罗恩病的ROC曲线下面积分别为0.952、0.726、0.799,最佳临界值分别为1.00×10^-3 mm²/s、26.50×10^-3 mm²/s、40.4%。结论：IVIM相关参数ADC值、D*值、f值对活动期克罗恩病有一定的诊断价值,其中ADC值的诊断效能最高。

Objective: To explore the performance of MRI intravoxel incoherent motion diffusion weighted imaging（IVIM-DWI） parameters in diagnosing active Crohn′s disease(CD). Methods: The MRI IVIM-DWI scan was performed on 30 patients with active ileocolonic CD diagnosed by endoscopy. The IVIM-DWI parameters, including apparent diffusion coefficient（ADC）, diffusion coefficient of the true water molecule （D）, microcirculation perfusion coefficient （D*） and perfusion fraction（f）, within the walls of involved ileocolon (CD group ) and normal intestinal at the same level (control group) were determined. The parameters were compared between CD and control groups. Receiver operator characteristic(ROC) analysis was performed to evaluate the diagnostic performance of each parameter. Results: ADC, D* and f values in CD group were significantly lower than those in control group (P<0.05). There was no statistically significant difference in D values between the two groups(P>0.05). The optimal cut-off value of ADC, D*, f for diagnosing CD were 1.00×10^-3 mm²/s, 26.50×10^-3 mm²/s, 40.4%, with the area under the ROC curves of 0.952, 0.726, 0.799, respectively. Conclusion: MRI intravoxel incoherent motion diffusion weighted imaging （IVIM-DWI） parameters, such as ADC, D*and f values, are helpful for diagnosis of active CD, and ADC value has the highest diagnostic performance.