脑MR弥散加权成像和弥散张量成像可比较图像参数的研究

目的研究正常人脑部弥散加权成像（DWI）的表观扩散系数（ADC）和不同弥散方向个数时的弥散张量成像（DTI）的平均扩散系数的异同。方法应用相控阵神经血管线圈,随机选择正常健康体检者进行DWI成像检查和6、15、25个梯度方向的DTI检查,各取得数据15例。对所有研究对象均进行了头颅常规MRI检查,均未发现异常。然后,用DTI分析软件DtiStiduo 2.4对获得的弥散加权像和弥散张量图像进行处理,得到DWI的平均ADC图像,DTI的张量的导出量——张量的特征值λ1、λ2、λ3,各向同性指标ADC、Trace（MD）的图像。对得到的每个研究对象相应图像中选取10个感兴趣区进行测量,得到相应的参数数值。结果 DWI（X、Y、Z三个方向正交扩散梯度）和6、16、25个扩散梯度方向的DTI所获得的ADC值没有显著性差异（P=0.579）;DWI、DTI的ADC值和MD值无显著性差异。结论 弥散成像中DWI和DTI中得到的ADC值具有可比性,可作为临床正常参考值。

Research of Comparable Image Parameters between DWI and DTI in Normal Brain MRI

Objective To compare ADC value of DWI and DTI in normal adult brain.Methods The routine MRI were performed in 27 healthy volunteers,in which 15 volunteers were performed with DWI or DTI with 6,15,25 diffusion gradient directions.Then analysed images of DWI and DTI with Dtistudio 2.4.ADC value of DWI,eigenvalues（λl,λ2,λ3） and Trace,ADC value of DTI are measured or calculated at 10 ROIs of all volvnteers image in DtiStudio 2.4 software.Statistical analysis was performed.Results ADC value is not affected by diffusion gradient directions（p0.05）.Conclusion There is no significance differences of ADC value of normal adult brain between DWI and DTI.