家兔肝纤维化模型体素内相位不相干运动成像研究

Intravoxel Incoherent Motion Diffusion Weighted MR in Rabbits of Liver Fibrosis Model

目的评价体素内相位不相干运动(IVIM)成像在家兔肝纤维化分期中的诊断价值。材料与方法构建家兔肝纤维化不同时期的模型,进行多b值(分别为0、50、100、200、300、800、1000、1200 s/mm^2)IVIM成像,并最终按肝纤维化病理分期相应将实验家兔分为S1~S4 4组,测量不同时期纤维化肝脏IVIM双指数模型扩散系数D值,灌注相关扩散系数D*值及灌注分数f值,比较对照组(仅注射生理盐水)与S1组、S2组与S3组的参数。结果对照组家兔D值高于S1组家兔,差异有统计学意义(P<0.05),而D*值及f值差异无统计学意义(P>0.05)。随着肝纤维化级别的增加,D、D*及f值也逐渐减低。其中,S2组与S3组的D*值差异有统计学意义(P<0.05),而D值和f值差异无统计学意义(P>0.05)。结论 D值有助于鉴别正常肝脏及肝纤维化S1期,D*值有助于鉴别S2及S3期的肝纤维化,而f值则不能发现早期肝纤维化,也不能帮助进行肝纤维化分期。IVIM成像提供了一种无创的肝纤维化早期及准确分期的方法,可为临床诊治提供帮助。

Purpose To evaluate the value of intravoxel incoherent motion（IVIM） imaging in diagnosis of liver fi brosis staging in rats. Materials and and Methods Rabbit models of liver fi brosis at different stages were established. All rabbits were divided into four groups based on the pathological results of fi brosis grading as S1-S4. The IVIM imagings with 8 b-values（0, 50, 100, 200, 300, 800, 1000, 1200 s/mm^2） were performed. The diffusion coeffi cient（D）, perfusion-related coeffi cient（D＊）, and perfusion fraction（f） were calculated and compared between control（only injection of saline） and S1 group, S2 and S3 group. Results Results The D value was signifi cantly lower in S1 group compared with control group（P〈0.05）, but the D＊ and f values showed no signifi cant difference between the two groups（both P〈0.05）. With the progression of liver fi brosis, the D, D＊ and f value decreased gradually; the D＊ value showed signifi cant difference between S2 and S3 group（P〈0.05）, but the D and f values showed no significant differences between the two groups（both P〈0.05）. Conclusion The D value is useful for differentiation of normal liver and hepatic fi brosis of S1 stage, while the D＊ is valuable for differentiation of hepatic fi brosis of S2 and S3 stage. However, the f value neither could detect early fi brosis, nor could differentiate hepatic fi brosis staging. IVIM imaging provides a noninvasive method for early and accurate staging of liver fi brosis, which may be of great help in clinical diagnosis and treatment.