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: 6615724
• 负责人: Jeffrey Frank Dunn
• 金额: $ 35.78万
• 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/6615724
• 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.

我们将设计并构建一个近红外（NIR）和磁共振（MR）成像系统，以研究脑氧合，并将其应用于脑缺氧/缺血的研究。大脑的正常功能以及诸如中风，窒息，肿瘤，脑积水和癫痫病等病理学的所有功能都会诱导氧合的变化。提供有关脑氧合的高空间和时间信息的成像方法将具有重大用途。该NIR/MR成像仪将提供有关脑氧利用，提取，血容量和血液饱和度的空间解决数据。主要目标是表明，通过使用MRI的结构信息，可以限制NIR数据的重建以获得真正的NIR图像。然后，我们可以将这些氧合图像与任何MR成像模态共同注册，包括扩散，灌注和大胆（血氧水平依赖性成像）。 NIR提供了有关血红蛋白含量和饱和度的准确信息，但是，没有我们提出的发展，NIR数据很难重建为图像。我们将验证针对一系列研究直径的NIRS重建算法。然后，我们将构建与NIBS成像系统兼容的合适的NMR硬件，并结合两者以创建混合成像模式。我们将在幻像和动物模型上对此进行测试。在开发系统之后，我们有两个假设驱动的目标，旨在展示成像仪的潜力，并提供有关低氧/缺血的独特数据。我们将检验以下假设：海马在常氧氧化期间具有高氧气的提取，并且在缺氧期间增加了提取能力。这种提取的差异可能是海马中缺氧敏感性提高的机制之一。我们还假设大脑的提取降低，并且在低温缺血后再灌注期间的脑血流。这种氧合模式与心肺旁路后神经系统障碍有关。另一方面，这是氧化后氧化损伤增加的时期，因此在某些情况下，再灌注过程中的氧合能量降低可能是有益的。我们将在常氧和体温过低期间评估脑组织氧合和血流（使用MR灌注成像）。该赠款将产生一种新型的成像方式，可以非侵入性地监测脑充氧，结构和血流。