弥散张量成像对皮质下失语症发病机制的研究

Mechanism of Subcortical Aphasia: A Diffusion Tensor Imaging Study

目的应用弥散张量成像(DTI)和纤维束示踪技术(DT-FT),探讨正常人语言功能区纤维连接特点以及皮质下失语症可能的发病机制。方法 2016年6月至2017年5月,选择正常被试20例和经MRI证实病变位于皮质下结构并表现为失语的脑卒中患者3例,根据西部失语成套测验评定标准,运动性失语2例,传导性失语1例。采用DTI及DT-FT观察语言功能区、对侧镜像区的各向异性(FA)以及纤维束的数量、走形等。结果正常被试语言功能区神经纤维走行十分复杂,与其他部位皮质和皮质下结构发生广泛联系,个体间差异不大。3例失语症患者中,语言功能区或弓状纤维束FA较对侧镜像区降低,纤维束破坏、数量减少、变形或移位。结论语言功能相关结构十分复杂,除皮质外,多种白质纤维束、皮质下结构也参与其中。语言功能区纤维受损、变形或移位,可能是皮质下失语症的发病机制。

Objective To explore the connection of fibers among functional language areas in the normals and the patients with subcortical aphasia using diffusion tensor imaging(DTI)and diffusion tensor fiber tractography(DT-FT).Methods From June,2016 to May,2017,20 healthy subjects and three stroke patients whose lesion located in subcortical structures were included.There were two patients with Broca's aphasia and one with conductive aphasia from the Western Aphasia Battery.They were scanned with DTI and DT-FT,while the fractional anisotropy(FA)of functional language areas and contralateral mirror areas were measured,and the relevant fibers were observed.Results The structures of functional language areas were complicated and extensively connected with other cortex and subcortical structures in healthy subjects,with few differences among individuals.FA was lower in the functional language areas and arcuate fasciculus than in the mirror regions in patients,and the fibers were damaged,distorted or shifted.Conclusion Structures related to language are very complicated,which involve cortex,lots of white matter tracts,subcortical structure and others.The damage,transformation or transposition of fibers in functional language areas may be the mechanism of subcortical aphasia.