Detection of traumatic axonal injury with diffusion tensor imaging in a mouse model of traumatic brain injury
Detection of traumatic axonal injury with diffusion tensor imaging in a mouse model of traumatic brain injury
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DOI：
10.1016/j.expneurol.2007.01.035
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发表时间：
2007-05-01
影响因子：
5.3
通讯作者：
Brody, D. L.
中科院分区：
文献类型：
--
作者：
Mac Donald, C. L.;Dikranian, K.;Brody, D. L.
创伤性轴索损伤(TAI)被认为是创伤性脑损伤(TBI)后认知功能障碍的主要原因，但TAI难以诊断或非侵袭性特征。弥散张量成像(DTI)在检测TAI方面有希望，但尚未与组织学证实的轴索损伤进行直接比较。在目前的研究中，小鼠接受DTI成像，接受中度皮质控制撞击损伤，并在损伤后4-6小时和24小时重新成像。用淀粉样β前体蛋白(APP)和神经丝免疫组织化学方法检测结节周围白质束轴突损伤情况。用APP染色组织切片的体视学方法对轴突损伤的严重程度进行量化。轴向弥散系数和相对各向异性两个DTI参数在损伤部位、结节周围和外囊均显著降低，而常规MRI在这些区域未见明显改变。挫伤在所有的MRI序列上都很容易被发现。在小鼠和跨越损伤空间梯度的亚区中，相对各向异性的变化与APP染色轴突的密度之间存在显著的相关性。使用有DTI改变的区域(海马连合)和无DTI改变的区域(前连合)来测试DTI的预测价值。与DTI预测一致的是，在海马区连合处有轴突损伤的组织学检测，而在前连合处没有。这些结果表明，DTI能够发现轴突损伤，并支持这一假说，DTI可能比传统的成像方法更敏感。(C)2007 Elsevier Inc.保留所有权利。
Traumatic axonal injury (TAI) is thought to be a major contributor to cognitive dysfunction following traumatic brain injury (TBI), however TAI is difficult to diagnose or characterize non-invasively. Diffusion tensor imaging (DTI) has shown promise in detecting TAI, but direct comparison to histologically-confirmed axonal injury has not been performed. In the current study, mice were imaged with DTI, subjected to a moderate cortical controlled impact injury, and re-imaged 4-6 h and 24 h post-injury. Axonal injury was detected by amyloid beta precursor protein (APP) and neurofilament immunohistochemistry in pericontusional white matter tracts. The severity of axonal injury was quantified using stereological methods from APP stained histological sections. Two DTI parameters - axial diffusivity and relative anisotropy - were significantly reduced in the injured, pericontusional corpus callosum and external capsule, while no significant changes were seen with conventional MRI in these regions. The contusion was easily detectable on all MRI sequences. Significant correlations were found between changes in relative anisotropy and the density of APP stained axons across mice and across subregions spanning the spatial gradient of injury. The predictive value of DTI was tested using a region with DTI changes (hippocampal commissure) and a region without DTI changes (anterior commissure). Consistent with DTI predictions, there was histological detection of axonal injury in the hippocampal commissure and none in the anterior commissure. These results demonstrate that DTI is able to detect axonal injury, and support the hypothesis that DTI may be more sensitive than conventional imaging methods for this purpose. (C) 2007 Elsevier Inc. All rights reserved.