Le Tuong H, Mukherjee Pratik, Henry Roland G, Berman Jeffrey I, Ware Marcus, Manley Geoffrey T
Department of Radiology, University of California, San Francisco, San Francisco, California.
Neurosurgery. 2005;56(1):189.
To demonstrate that magnetic resonance diffusion tensor imaging (DTI) with three-dimensional (3-D) fiber tractography can visualize traumatic axonal shearing injury that results in posterior callosal disconnection syndrome.
A 22-year-old man underwent serial magnetic resonance imaging 3 days and 12 weeks after blunt head injury. The magnetic resonance images included whole-brain DTI acquired with a single-shot spin echo echoplanar sequence. 3-D DTI fiber tractography of the splenium of the corpus callosum was performed. Quantitative DTI parameters, including apparent diffusion coefficient and fractional anisotropy, from the site of splenial injury were compared with those of a normal adult male volunteer.
Conventional magnetic resonance images revealed findings of diffuse axonal injury, including a lesion at the midline of the splenium of the corpus callosum. DTI performed 3 days posttrauma revealed that the splenial lesion had reduced apparent diffusion coefficient and fractional anisotropy, reflecting a large decrease in the magnitude of diffusion parallel to the white matter fibers, which had partially recovered as revealed by follow-up DTI 12 weeks postinjury. 3-D tractography revealed an interruption of the white matter fibers in the posteroinferior aspect of the splenium that correlated with the patient's left hemialexia, a functional deficit caused by disconnection of the right visual cortex from the language centers of the dominant left hemisphere.
DTI with 3-D fiber tractography can visualize acute axonal shearing injury, which may have prognostic value for the cognitive and neurological sequelae of traumatic brain injury.
证明三维（3-D）纤维束成像的磁共振扩散张量成像（DTI）能够显示导致胼胝体后连合分离综合征的创伤性轴索剪切损伤。
一名22岁男性在钝性头部损伤后3天和12周接受了系列磁共振成像检查。磁共振图像包括采用单次激发自旋回波平面回波序列采集的全脑DTI。对胼胝体压部进行了三维DTI纤维束成像。将胼胝体压部损伤部位的定量DTI参数，包括表观扩散系数和各向异性分数，与一名正常成年男性志愿者的参数进行比较。
常规磁共振图像显示了弥漫性轴索损伤的表现，包括胼胝体压部中线处的一个病灶。创伤后3天进行的DTI显示，胼胝体压部病灶的表观扩散系数和各向异性分数降低，反映了与白质纤维平行的扩散幅度大幅下降，损伤后12周的随访DTI显示部分已经恢复。三维纤维束成像显示胼胝体压部后下方的白质纤维中断，这与患者的左侧半失读症相关，左侧半失读症是一种由右侧视觉皮层与优势半球左侧语言中枢分离引起的功能缺陷。
三维纤维束成像的DTI能够显示急性轴索剪切损伤，这可能对创伤性脑损伤的认知和神经后遗症具有预后价值。
