Traumatic brain injury leads to significant loss of brain volume, which continues into the chronic stage. This can be sensitively measured using volumetric analysis of MRI. Here we: (i) investigated longitudinal patterns of brain atrophy; (ii) tested whether atrophy is greatest in sulcal cortical regions; and (iii) showed how atrophy could be used to power intervention trials aimed at slowing neurodegeneration. In 61 patients with moderate-severe traumatic brain injury (mean age = 41.55 years ± 12.77) and 32 healthy controls (mean age = 34.22 years ± 10.29), cross-sectional and longitudinal (1-year follow-up) brain structure was assessed using voxel-based morphometry on T₁-weighted scans. Longitudinal brain volume changes were characterized using a novel neuroimaging analysis pipeline that generates a Jacobian determinant metric, reflecting spatial warping between baseline and follow-up scans. Jacobian determinant values were summarized regionally and compared with clinical and neuropsychological measures. Patients with traumatic brain injury showed lower grey and white matter volume in multiple brain regions compared to controls at baseline. Atrophy over 1 year was pronounced following traumatic brain injury. Patients with traumatic brain injury lost a mean (± standard deviation) of 1.55% ± 2.19 of grey matter volume per year, 1.49% ± 2.20 of white matter volume or 1.51% ± 1.60 of whole brain volume. Healthy controls lost 0.55% ± 1.13 of grey matter volume and gained 0.26% ± 1.11 of white matter volume; equating to a 0.22% ± 0.83 reduction in whole brain volume. Atrophy was greatest in white matter, where the majority (84%) of regions were affected. This effect was independent of and substantially greater than that of ageing. Increased atrophy was also seen in cortical sulci compared to gyri. There was no relationship between atrophy and time since injury or age at baseline. Atrophy rates were related to memory performance at the end of the follow-up period, as well as to changes in memory performance, prior to multiple comparison correction. In conclusion, traumatic brain injury results in progressive loss of brain tissue volume, which continues for many years post-injury. Atrophy is most prominent in the white matter, but is also more pronounced in cortical sulci compared to gyri. These findings suggest the Jacobian determinant provides a method of quantifying brain atrophy following a traumatic brain injury and is informative in determining the long-term neurodegenerative effects after injury. Power calculations indicate that Jacobian determinant images are an efficient surrogate marker in clinical trials of neuroprotective therapeutics.

中文翻译：

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中重度创伤性脑损伤后进行性脑容量减少的空间模式

创伤性脑损伤导致脑容量显着减少，并持续到慢性阶段。这可以使用 MRI 的体积分析灵敏地测量。在这里，我们：（i）研究了脑萎缩的纵向模式；(ii) 测试脑沟皮质区的萎缩是否最大；(iii) 展示了如何利用萎缩来为旨在减缓神经退行性变的干预试验提供动力。在 61 名中重度创伤性脑损伤患者（平均年龄 = 41.55 岁 ± 12.77）和 32 名健康对照者（平均年龄 = 34.22 岁 ± 10.29）中，评估了横断面和纵向（1 年随访）脑结构在 T ₁上使用基于体素的形态测量加权扫描。纵向脑容量变化使用一种新的神经影像分析管道进行表征，该管道生成雅可比行列式度量，反映基线和后续扫描之间的空间扭曲。雅可比行列式值在区域内进行总结，并与临床和神经心理学测量值进行比较。与基线时的对照组相比，创伤性脑损伤患者在多个脑区显示出较低的灰质和白质体积。创伤性脑损伤后明显萎缩超过 1 年。创伤性脑损伤患者每年平均损失 1.55% ± 2.19 的灰质体积、1.49% ± 2.20 的白质体积或 1.51% ± 1.60 的全脑体积。健康对照组灰质体积减少 0.55% ± 1.13，白质体积增加 0.26% ± 1.11；相当于整个脑容量减少 0.22% ± 0.83。白质萎缩最为严重，其中大部分（84%）区域受到影响。这种影响与衰老无关，而且明显大于衰老。与脑回相比，皮质沟的萎缩也增加了。萎缩与受伤后的时间或基线年龄之间没有关系。萎缩率与随访期结束时的记忆性能以及多重比较校正之前的记忆性能变化有关。总之，创伤性脑损伤会导致脑组织体积逐渐减少，并在损伤后持续多年。萎缩在白质中最为突出，但与脑回相比，在皮质沟中也更为明显。这些发现表明，雅可比行列式提供了一种量化创伤性脑损伤后脑萎缩的方法，并且在确定损伤后的长期神经退行性影响方面提供了信息。功效计算表明雅可比行列式图像是神经保护疗法临床试验中的有效替代标记。