Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
Applied Physics Laboratory, University of Washington, Seattle, WA, USA.
Exp Neurol. 2024 Apr;374:114681. doi: 10.1016/j.expneurol.2024.114681. Epub 2024 Jan 8.
Spinal cord injury is characterized by hemodynamic disruption at the injury epicenter and hypoperfusion in the penumbra, resulting in progressive ischemia and cell death. This degenerative secondary injury process has been well-described, though mostly using ex vivo or depth-limited optical imaging techniques. Intravital contrast-enhanced ultrasound enables longitudinal, quantitative evaluation of anatomical and hemodynamic changes in vivo through the entire spinal parenchyma. Here, we used ultrasound imaging to visualize and quantify subacute injury expansion (through 72 h post-injury) in a rodent cervical contusion model. Significant intraparenchymal hematoma expansion was observed through 72 h post-injury (1.86 ± 0.17-fold change from acute, p < 0.05), while the volume of the ischemic deficit largely increased within 24 h post-injury (2.24 ± 0.27-fold, p < 0.05). Histology corroborated these findings; increased apoptosis, tissue and vessel loss, and sustained tissue hypoxia were observed at 72 h post-injury. Vascular resistance was significantly elevated in the remaining perfused tissue, likely due in part to deformation of the central sulcal artery nearest to the lesion site. In conjunction, substantial hyperemia was observed in all perilesional areas examined except the ipsilesional gray matter. This study demonstrates the utility of longitudinal ultrasound imaging as a quantitative tool for tracking injury progression in vivo.
脊髓损伤的特征是损伤中心的血液动力学紊乱和半影区的灌注不足，导致进行性缺血和细胞死亡。尽管大多数使用的是离体或深度受限的光学成像技术，但这种退行性的二次损伤过程已经得到了很好的描述。活体对比增强超声通过整个脊髓实质实现了对解剖和血液动力学变化的纵向、定量评估。在这里，我们使用超声成像技术可视化和量化了啮齿动物颈挫伤模型中的亚急性损伤扩展（至损伤后 72 小时）。损伤后 72 小时内观察到明显的脑实质血肿扩展（与急性相比增加了 1.86±0.17 倍，p<0.05），而缺血性缺损的体积在损伤后 24 小时内大大增加（增加了 2.24±0.27 倍，p<0.05）。组织学结果证实了这些发现；在损伤后 72 小时观察到细胞凋亡增加、组织和血管丢失以及持续的组织缺氧。在剩余的灌注组织中，血管阻力显著升高，这可能部分归因于靠近损伤部位的中央脑沟动脉的变形。同时，在所有检查的损伤周围区域观察到明显的充血，除了同侧灰质。这项研究表明，纵向超声成像作为一种活体追踪损伤进展的定量工具具有实用性。
