Near infrared/MR system for imaging brain oxygenation

用于脑氧合成像的近红外/MR系统

• 批准号: 6326330
• 负责人: Jeffrey Frank Dunn
• 金额: $ 38.81万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6326330
• 关键词: bioimaging /biomedical imaging; blood flow measurement; brain circulation; brain disorder diagnosis; cerebral ischemia /hypoxia; cerebrovascular imaging /visualization; diagnosis design /evaluation; hippocampus; image enhancement; infrared spectrometry; laboratory rat; magnetic resonance imaging; noninvasive diagnosis; oxygen tension; oxygen transport; phantom model; technology /technique development

We will design, and construct a combined near infrared (NIR) and magnetic resonance (MR) imaging system for studying brain oxygenation, and apply it to the study of brain hypoxia/ischemia. Normal function of brain, as well as pathologies such as stroke, birth asphyxia, tumors, hydrocephalus and epilepsy all induce changes in oxygenation. Imaging methods which provide high spatial and temporal information concerning brain oxygenation would be of significant use. This NIR/MR imager will provide spatially resolved data on cerebral oxygen utilization, extraction, blood volume and blood saturation. The main goal is to show that, by using structural information from the MRI, one can constrain the reconstruction of NIR data to obtain true NIR images. We can then co-register these oxygenation images with any MR imaging modality including diffusion, perfusion and BOLD (blood oxygen level dependent imaging). NIR provides accurate information on hemoglobin content and saturation but, without the developments which we propose, NIR data are difficult to reconstruct into an image. We will verify NIRS reconstruction algorithms for a range of study diameters. Then we will construct appropriate NMR hardware compatible with the NIBS imaging system and combine the two to create the hybrid imaging modality. We will test this on phantoms and on animal models. After developing the system, we have two hypothesis driven aims designed to show the potential of the imager, as well as to provide unique data on hypoxia/ischemia. We will test the hypothesis that the hippocampus has a high oxygen extraction during normoxia, and reduced capacity to increase extraction during hypoxia. This difference in extraction may be one of the mechanisms of increased hypoxia sensitivity in the hippocampus. We also hypothesize that the brain has a reduced extraction, and cerebral blood flow during reperfusion after hypothermic ischemia. Such a pattern of oxygenation has been implicated in neurological impairment after cardiopulmonary bypass. On the other hand, this is the period of increased oxidative damage post-ischemia, and so reduced oxygenation during reperfusion may be beneficial under some situations. We will assess brain tissue oxygenation and blood flow (using MR perfusion imaging) during ischemia/reperfusion during normoxia and hypothermia. This grant will produce a novel imaging modality which can non-invasively monitor cerebral oxygenation, structure, and blood flow.

我们将设计并建构一套结合近红外线与磁共振技术的脑氧合影像系统，并将其应用于脑缺氧/缺血的研究。脑的正常功能以及诸如中风、出生窒息、肿瘤、脑积水和癫痫的病理都引起氧合的变化。提供关于脑氧合的高空间和时间信息的成像方法将是重要的用途。该NIR/MR成像仪将提供关于脑氧利用、提取、血容量和血液饱和度的空间分辨数据。主要目标是表明，通过使用来自MRI的结构信息，可以约束NIR数据的重建以获得真实的NIR图像。然后，我们可以将这些氧合图像与任何MR成像模式（包括扩散、灌注和BOLD（血氧水平依赖性成像））进行配准。近红外提供了准确的信息，血红蛋白含量和饱和度，但没有我们提出的发展，近红外数据是难以重建成图像。我们将验证一系列研究直径的NIRS重建算法。然后，我们将构建与NIBS成像系统兼容的适当的NMR硬件，并将两者联合收割机组合以创建混合成像模态。我们将在幻影和动物模型上进行测试。在开发该系统后，我们有两个假设驱动的目的，旨在显示成像仪的潜力，以及提供缺氧/缺血的独特数据。我们将测试海马在常氧期间具有高氧提取，并且在缺氧期间增加提取的能力降低的假设。提取的这种差异可能是海马缺氧敏感性增加的机制之一。我们还假设，在低温缺血后的再灌注过程中，大脑的提取和脑血流量减少。这种氧合模式与心肺转流术后的神经损伤有关。另一方面，这是缺血后氧化损伤增加的时期，因此在某些情况下，再灌注期间减少氧合可能是有益的。我们将在常氧和低温条件下评估缺血/再灌注期间的脑组织氧合和血流（使用MR灌注成像）。这项资助将产生一种新的成像方式，可以非侵入性地监测脑氧合，结构和血流。