【摘要】 目的　运用弥散张量成像 (DTI)方法来探讨脑内不同组织及解剖部位的弥散各向异性特点。资料与方法　采用单次激发自旋回波EPI成像序列 ,将弥散敏感梯度依次施加在六个不同 (P、M、S、MP、PS、MS)的方向进行DTI,获得正常成人脑的弥散张量图及各向异性指数图 ,在脑内不同解剖部位进行各向异性指数、张量的轨迹及平均弥散率测定并进行统计学分析。结果　脑内不同组织及解剖部位的弥散各向异性程度不同 ,脑白质的弥散各向异性远大于丘脑与脑灰质 (P <0 .0 1) ;在脑白质的不同解剖部位 ,其各向异性特点也不相同 (P <0 .0 5 ) ,脑白质连合纤维 (胼胝体 )的各向异性程度最高 ,其次为脑白质的投射纤维 (内囊 ) ,再次为联合纤维 (半卵圆中心 )。张量的轨迹及平均弥散率在脑内的不同部位具有一致性。结论　DTI可准确测定脑内不同组织弥散的各向异性特点 ,并且可清晰显示脑内神经纤维束的方向及走行 ,可为临床脑白质病的研究提供新的功能测定方法更多还原

【Abstract】 Objective To explore the diffusion anisotropic features of different tissues and structures of normal adult brain by using magnetic resonance diffusion tensor imaging, and to obtain normative human cerebral data, including anisotropic index, trace of diffuse tensor (Trace D) and diffusivity.Materials and Methods Diffusion tensor imaging (DTI) was performed using single shot spin echo echo-planar sequence, and diffusion was measured along six different directions. Anisotropic index, trace D and diffusivity were measured and compared between different cerebral regions on the maps of Trace D and anisotropic index. Results Diffusion anisotropy was significantly different from region to region in the brain. Diffusion anisotropy of the white matter was much larger than that of thalamus and gray matter. Diffusion anisotropy was significantly different among different parts of white matter, with the commissural neurofibers of white matter (corpus callosum) having the highest value, followed by projection fibers (internal capsule) and association fibers (centerum semiovale). No significant difference in Trace D and diffusivity was found.Conclusion DTI can precisely determine the diffusion anisotropic properties of different intracerebral tissues and can well display intracerebral neurofibers, providing a new functional examination for the clinical study of leukoencephalopathy.更多还原