Rapid screening for stroke in pre-hospital settings may improve patient outcomes by allowing early deployment of thrombolytic therapies. Near-infrared hybrid diffuse optical screening devices may fill this need. This study seeks to determine whether hybrid diffuse optical measurements can measure hemodynamic changes associated with cerebral ischemia within the first few hours of the onset of acute ischemia in a large animal model. A hybrid diffuse optical device combining of near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) was fabricated to measure total hemoglobin concentration (HbT), tissue oxygen saturation (StO 2 ) and blood flow index (BFI). Cerebral ischemia was induced by ligation of the bilateral common carotid arteries (CCA) in five miniature pigs. Additionally, a fatal stroke was induced in two pigs by injecting 5ml air emboli into both CCA. Cerebral hemodynamic parameters were monitored continuously throughout the study with the hybrid optical device. Relative changes BFI showed the good repeatability both of the ligation and fatal stroke experiments. During bilateral CCA ligation, the BFI decreased by up to about 66% of baseline values; during the fatal stroke experiment, the BFI decreased by up to about 95%, with a temporal resolution of 20 seconds. To the best of our knowledge, there are not existing methods which can measure the cerebral ischemia within the first few hours of the onset noninvasively. The MRI scanning was conducted at 24 h post injury. However, the images showed no abnormality. The results show the hybrid diffuse optical method can immediately measure the hemodynamic changes of miniature pigs in the first few hours of each single cerebral ischemia onset, and the BFI may be the promising biomarker to distinguish the cerebral ischemia and cerebral death.

中文翻译：

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猪模型急性脑缺血后血流动力学变化的混合漫射光学监测

在院前环境中快速筛查中风可能会通过尽早部署溶栓治疗来改善患者预后。近红外混合漫射光学筛选设备可以满足这一需求。这项研究旨在确定大型动物模型在急性缺血发作的最初几个小时内，混合漫射光学测量是否可以测量与脑缺血相关的血液动力学变化。制造了一种将近红外光谱（NIRS）和散射相关光谱（DCS）相结合的混合漫射光学器件，以测量总血红蛋白浓度（HbT），组织氧饱和度（StO 2）和血流指数（BFI）。通过结扎五只小型猪的双侧颈总动脉（CCA）诱发脑缺血。另外，通过向两个CCA注射5ml空气栓塞，在两只猪中诱发致命性中风。在整个研究过程中，使用混合光学设备连续监测脑血流动力学参数。相对变化BFI显示结扎和致命性中风实验均具有良好的重复性。在双侧CCA结扎过程中，BFI下降了多达基线值的约66％。在致命性中风实验中，BFI下降了约95％，时间分辨率为20秒。据我们所知，尚无现有方法可在无创性发作的最初几个小时内测量脑缺血。受伤后24小时进行MRI扫描。但是，图像未显示异常。