Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Department of Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan; Translational Imaging Research Center, Taipei Medical University Hospital, Taipei, Taiwan.
Magn Reson Imaging. 2024 Oct;112:47-53. doi: 10.1016/j.mri.2024.06.003. Epub 2024 Jun 21.
Although ischemia-reperfusion (I/R) injury varies between cortical and subcortical regions, its effects on specific regions remain unclear. In this study, we used various magnetic resonance imaging (MRI) techniques to examine the spatiotemporal dynamics of I/R injury within the salvaged ischemic penumbra (IP) and reperfused ischemic core (IC) of a rodent model, with the aim of enhancing therapeutic strategies by elucidating these dynamics.
A total of 17 Sprague-Dawley rats were subjected to 1 h of transient middle cerebral artery occlusion with a suture model. MRI, including diffusion tensor imaging (DTI), T2-weighted imaging, perfusion-weighted imaging, and T1 mapping, was conducted at multiple time points for up to 5 days during the I/R phases. The spatiotemporal dynamics of blood-brain barrier (BBB) modifications were characterized through changes in T1 within the IP and IC regions and compared with mean diffusivity (MD), T2, and cerebral blood flow.
During the I/R phases, the MD of the IC initially decreased, normalized after recanalization, decreased again at 24 h, and peaked on day 5. By contrast, the IP remained relatively stable. Both the IP and IC exhibited hyperperfusion, with the IP reaching its peak at 24 h, followed by resolution, whereas hyperperfusion was maintained in the IC until day 5. Despite hyperperfusion, the IP maintained an intact BBB, whereas the IC experienced persistent BBB leakage. At 24 h, the IC exhibited an increase in the T2 signal, corresponding to regions exhibiting BBB disruption at 5 days.
Hyperperfusion and BBB impairment have distinct patterns in the IP and IC. Quantitative T1 mapping may serve as a supplementary tool for the early detection of malignant hyperemia accompanied by BBB leakage, aiding in precise interventions after recanalization. These findings underscore the value of MRI markers in monitoring ischemia-specific regions and customizing therapeutic strategies to improve patient outcomes.
尽管皮质和皮质下区域的缺血再灌注（I/R）损伤存在差异，但特定区域的损伤影响仍不清楚。在这项研究中，我们使用各种磁共振成像（MRI）技术检查了啮齿动物模型中缺血半影区（IP）和再灌注缺血核心区（IC）内的 I/R 损伤的时空动力学，旨在通过阐明这些动力学来增强治疗策略。
总共 17 只 Sprague-Dawley 大鼠采用缝线模型进行 1 小时短暂性大脑中动脉闭塞。在 I/R 期间，在多达 5 天的时间内进行了多次 MRI，包括弥散张量成像（DTI）、T2 加权成像、灌注加权成像和 T1 映射。通过 IP 和 IC 区域内 T1 的变化来描述血脑屏障（BBB）变化的时空动力学，并与平均弥散度（MD）、T2 和脑血流进行比较。
在 I/R 期间，IC 的 MD 最初降低，再通后恢复正常，24 小时后再次降低，并在第 5 天达到峰值。相比之下，IP 保持相对稳定。IP 和 IC 均表现为过度灌注，IP 在 24 小时达到峰值，然后缓解，而 IC 中的过度灌注一直持续到第 5 天。尽管存在过度灌注，IP 仍保持完整的 BBB，而 IC 则持续存在 BBB 渗漏。在 24 小时时，IC 出现 T2 信号增加，与第 5 天 BBB 破坏的区域相对应。
在 IP 和 IC 中，过度灌注和 BBB 损伤具有不同的模式。定量 T1 映射可能成为检测伴有 BBB 渗漏的恶性充血的辅助工具，有助于再通后的精确干预。这些发现强调了 MRI 标志物在监测缺血特异性区域和定制治疗策略以改善患者预后方面的价值。
