Understanding the mechanisms of atrophy associated with spinal cord injury: the application of MRI-based in vivo histology and ex vivo histology

脊髓损伤（Spinal cord injury，SCI）主要是由暴力、交通和运动事故等创伤性事件引起的。截瘫（腿部瘫痪）和四肢瘫痪（腿部和手臂瘫痪）永久，严重和显着降低受影响的人的生活质量以及他们保持劳动力的能力。这些负面后果的出现是因为SCI后的功能恢复仍然有限，大多数患者在长期内留下严重的损伤。虽然康复训练可以改善SCI后的临床结果，这对患者的生活质量是一个主要的好处，但退行性过程和支持任何神经和功能恢复的机制还没有得到很好的理解。磁共振成像（MRI）领域的最新进展极大地改善了我们如何可视化和询问中枢神经系统的结构组织和功能。在这些进展中值得注意的是研究人类中枢神经系统“微观”变化的能力。这包括区分白色和灰质--脊髓、脑干和大脑结构的两个基本部分。使用显微镜MRI协议，我们已经表明，随着时间的推移发生的结构变化遵循特定的空间和时间模式。事实上，这些变化发生在受伤后的早期，发生在脊髓和大脑中。然而，到目前为止，可能构成所观察到的变化基础的生物变化范围还无法解开。通过使用MRI（hMRI）的体内组织学-MRI中的一个新兴领域-我们的目标是建立测量的MRI信号和底层组织微观结构变化之间的缺失环节，这将有助于我们解释和更好地理解与脊髓损伤相关的疾病过程。

Spinal cord injuries (SCI) are mainly caused by traumatic events such as violence and traffic and sports accidents. Paraplegia (paralysis of the legs) and tetraplegia (paralysis of both legs and arms) permanently, severely and dramatically reduce the quality of life of the affected person as well as their ability to remain a member of the workforce. These negative consequences arise because functional recovery following SCI remains limited and the majority of patients are left with severe impairments in the longer term. While rehabilitative training can improve clinical outcome following SCI, which is a major benefit to the patients' quality of life, the degenerative processes and the mechanisms underpinning any neurological and functional recovery are not well understood. Recent advances in the field of magnetic resonance imaging (MRI) have vastly improved how we can visualize and interrogate the structural organisation and functioning of the central nervous system. Notable among these advances is the emerging ability to investigate "microscopic" changes in the human central nervous system. This includes distinguishing white and grey matter - two fundamental divisions of structure in the spinal cord, brainstem and brain. Using microscopic MRI protocols we have shown that structural changes occur over time following a specific spatial and temporal pattern. In fact these changes occur early after the injury and happen both in the cord and in the brain. However so far, the range of biological changes that may underlie the observed changes cannot be disentangled. By means of in vivo histology using MRI (hMRI) - an emerging field in MRI - we aim to establish the missing link between measured MRI signals and changes in the underlying tissue microstructure, which will help us to explain and better understand the disease processes associated with spinal cord injury.