Cohen-Adad J, Benali H, Hoge R D, Rossignol S
Groupe de Recherche sur le Système Nerveux Central, Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada; INSERM U678, Université Pierre et Marie Curie (Paris VI), CHU Pitié-Salpêtrière, Paris, France; Unité de Neuroimagerie Fonctionnelle, CRIUGM, Université de Montréal, Montreal, QC, Canada; Institute of Biomedical Engineering, Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada.
INSERM U678, Université Pierre et Marie Curie (Paris VI), CHU Pitié-Salpêtrière, Paris, France; Unité de Neuroimagerie Fonctionnelle, CRIUGM, Université de Montréal, Montreal, QC, Canada.
Neuroimage. 2008 Apr 1;40(2):685-697. doi: 10.1016/j.neuroimage.2007.11.031. Epub 2007 Dec 3.
Spinal cord diffusion tensor imaging (DTI) is challenging in many ways: the small size of the cord, physiological motion and susceptibility artifacts pose daunting obstacles to the acquisition of high-quality data. Here, we present DTI results computed from in vivo studies of the healthy and injured spinal cord of five cats. Both high spatial (1.1 mm3) and angular (55 directions) resolutions were used to optimise modelling of the diffusion process. Also, particular effort was directed towards a strategy that limits susceptibility artifacts. For validation purposes, acquisitions were repeated in two cats before and after making a spinal lesion. As a result, various axonal trajectories were identified by tractography including dorsal and ventral columns as well as lateral tracts. Also, fibre bundles showed robust disruption at the site of spinal cord injuries (partial and complete) via tractography, accompanied with significantly lower fractional anisotropy values at the site of lesions. Important outcomes of this work are (i) tractography-based localisation of anatomical tracts in the thoraco-lumbar spinal cord and (ii) in vivo assessment of axonal integrity following experimental spinal cord injury.
脊髓扩散张量成像（DTI）在很多方面都具有挑战性：脊髓体积小、生理运动以及磁敏感伪影给高质量数据采集带来了巨大障碍。在此，我们展示了对五只猫的健康和损伤脊髓进行活体研究所得的DTI结果。高空间分辨率（1.1立方毫米）和角分辨率（55个方向）均被用于优化扩散过程的建模。此外，还特别致力于采用一种限制磁敏感伪影的策略。为了进行验证，在两只猫制造脊髓损伤前后均重复进行了采集。结果，通过纤维束成像识别出了各种轴突轨迹，包括背柱和腹柱以及外侧束。此外，通过纤维束成像显示，在脊髓损伤部位（部分损伤和完全损伤）纤维束出现明显中断，损伤部位的各向异性分数值显著降低。这项工作的重要成果包括：（i）基于纤维束成像对胸腰段脊髓中的解剖束进行定位，以及（ii）对实验性脊髓损伤后轴突完整性进行活体评估。
