【摘要】 目的 获取正常人脑组织扩散张力性图像(diffusion densor imaging，DTI)，定量分析正常人脑组织水扩散的内在特性，进一步评价脑解剖结构。 方法 60例健康正常人，应用单次激发EPI-DW序列，计算出ADCiso图及各向异性图，分析脑实质不同区域的解剖结构，测量ADCiso(Isotropic Apparent Diffusion Coefficient)及各向异性指数。 结果 (1)脑内不同组织结构弥散特性不同，脑白质弥散表现为各向异性，而脑灰质弥散表现为各向同性。(2)脑组织的弥散特性不受年龄因素影响。(3)弥散张量-脑白质纤维束成像术可清晰显示脑白质纤维束的方向及走行。 结论 各向异性图能更好地显示脑白质的纤维微结构，定量分析水分子的扩散特点，区分不同白质的组织学类型，对神经功能解剖学和神经系统病变的研究提供了一种新的功能成像方法。

    【关键词】 正常成人脑组织 扩散成像 张量

    MR Diffusion tensor imaging study of the normal adult human brain

    Yuan Xiaoping，Zhang Rong，Yuan Jianpeng

    Department of Radiology，The Second Affiliated Hospital of Sun Yat-Sen University，Guangzhou510120.

    【Abstract】 Objective To obtain the diffusion tensor maps of the normal human brain，and assess intrinstic properties of water diffusion in quantitative parameters for an anatomic analysis.Methods Maps of isotropic apparent diffusion coefficient and various anisotropic maps were calculated in60healthy adults from seven diffusion imagings by using single-shot echo-planar diffusion-weighted sequence.Brain parenchyma anatomy was analyzed and ADCiso and various anisotropic index were measured.Results (1)Diffusion properties of different tissues and anatomic areas of normal adult human brain are different.Diffusion in white matter is anisotropic;diffusion in gray matter is isotropic.(2)Tissues diffusion doses not differ with age.(3)Diffusion-tensor tractography can display the direction and pathway of the major tract.Conclusion DTI can be obtained rapidly and demonstrate more subtle WM anatomy than conven-tional MR ......