Department of Neurosurgery, Hospital Universitario 12 de Octubre, Complutense University of Madrid, Madrid, Spain.
Department of Radiology, Hospital Universitario 12 de Octubre, Complutense University of Madrid, Madrid, Spain.
J Neurotrauma. 2019 Oct 1;36(19):2785-2802. doi: 10.1089/neu.2018.5978. Epub 2019 Jun 7.
Traumatic axonal injury (TAI) is the main cause of cognitive and psychological disfunction after a traumatic brain injury (TBI). Diffusion tensor imaging (DTI) is considered a useful technique for indirect assessment of white matter (WM) integrity after a TBI. Scattered WM alterations and its relationship with patient severity have been discovered in normal appearing conventional magnetic resonance imaging (MRI) studies based on DTI sequences. However, there is a lack of large sample studies on the longitudinal changes of DTI metrics to be used to determine the temporal profile after head injury and its association with patient outcome. We performed a prospective observational study in 118 moderate-to-severe TBI patients. The study included clinical outcome assessment based on the Glasgow Outcome Scale Extended (GOSE) and serial DTI studies in the early subacute setting (< 60 days) and 6 and 12 months after injury. Fractional anisotropy (FA) and axial and radial diffusivities (AD and RD, respectively) were measured in the three portions of corpus callosum (genu, body, splenium) at each time-point and compared with normalized values from an age-matched control group. Longitudinal FA analysis and its correlation with patient improvement also was done by non-parametric testing and ordinal regression analysis. Our main results indicated that between all the time-points, dynamic changes in DTI metrics in all three portions of corpus callosum were detected, but TBI patients continued to show significantly lower FA and AD values and higher RD values compared with controls. We also have discovered differences in the change of DTI metrics among different time-points in patient subgroups according with their outcome improvement. In conclusion, even without normalization of DTI metrics in the long-term, knowledge of the temporal profile of change in DTI metrics can provide important information about patients' clinical recovery after TBI.
创伤性轴索损伤（TAI）是创伤性脑损伤（TBI）后认知和心理功能障碍的主要原因。弥散张量成像（DTI）被认为是间接评估 TBI 后白质（WM）完整性的有用技术。在基于 DTI 序列的常规磁共振成像（MRI）研究中，发现正常表现的 WM 改变及其与患者严重程度的关系。然而，缺乏关于 DTI 指标的纵向变化的大样本研究，这些变化可用于确定头部损伤后的时间分布及其与患者预后的关系。我们对 118 例中重度 TBI 患者进行了前瞻性观察性研究。该研究包括基于格拉斯哥结局量表扩展版（GOSE）的临床预后评估，以及早期亚急性期（<60 天）和损伤后 6 个月和 12 个月的连续 DTI 研究。在每个时间点，测量胼胝体的三个部分（膝部、体部、压部）的分数各向异性（FA）和轴向和径向扩散系数（AD 和 RD），并与年龄匹配对照组的归一化值进行比较。还通过非参数检验和有序回归分析进行了纵向 FA 分析及其与患者改善的相关性。我们的主要结果表明，在所有时间点之间，均检测到胼胝体三个部分的 DTI 指标的动态变化，但与对照组相比，TBI 患者的 FA 和 AD 值仍然显著降低，RD 值仍然显著升高。我们还发现，根据患者预后改善情况，不同时间点的 DTI 指标变化在患者亚组中存在差异。总之，即使不进行 DTI 指标的长期归一化，了解 DTI 指标变化的时间分布也可以为 TBI 后患者的临床恢复提供重要信息。
