Oxygenation Fingerprinting with MRI for Ischemic Stroke

描述（由申请人提供）：动机急性缺血性卒中的中心事件之一是大脑供氧减少，导致细胞死亡和不可逆损伤。为了解决这个问题，大脑有增加从动脉血中提取氧气的机制，这可以用氧-15正电子发射断层扫描（PET）成像。来自PET的一些证据表明，氧提取分数（OEF）增加的区域在缺血性卒中中特别脆弱。鉴于MRI对顺磁脱氧血红蛋白的敏感性（BOLD效应的基础），可以成像组织氧饱和度（SO2）。本研究的动机是实施和验证两种有前途的MR氧合方法，多参数定量BOLD和MR氧合指纹识别在脑卒中患者中的应用。后一种技术建立在开创性工作的基础上，将指纹识别方法从解剖成像扩展到生理成像。在两年的时间里，我们的目标是进行研究，以验证这两种MR氧合成像方案在暴露于激发气体挑战的正常受试者中的性能，这将改变整个脑氧合。然后，我们将这两种技术中的最佳应用于急性缺血性卒中患者队列，以确定氧-扩散（O2- DWI）失配的性能，作为传统DWI- pwi失配的潜在改进替代品。我们相信，通过验证一种基于非侵入性mri的组织氧合评估方法，成功实现这些目标将显著改善急性卒中护理。我们相信，一种强大的MR氧合方法的发展将在广泛的其他神经系统疾病中产生广泛的益处，包括颈动脉狭窄闭塞性疾病、脑肿瘤、多发性硬化症和神经退行性疾病。

DESCRIPTION (provided by applicant): MOTIVATION One of the central events in acute ischemic stroke is the decrease in delivery of oxygen to the brain, which leads to cell death and irreversible injury. To counteract this, the brain has mechanisms to increase its extraction of oxygen from the arterial blood, which can be imaged with oxygen-15 positron emission tomography (PET). Some evidence from PET exists that suggests that regions with increased oxygen extraction fraction (OEF) are particularly vulnerable in ischemic stroke. Given the sensitivity of MRI to paramagnetic deoxy- hemoglobin (the basis of the BOLD effect), it is possible to image tissue oxygen saturation (SO2). The motivation for the current study is to implement and validate two promising MR oxygenation methods, multiparametric quantitative BOLD and MR oxygenation fingerprinting for use in stroke patients. This latter technique builds on pioneering work extending the fingerprinting approach from anatomical to physiological imaging. AIMS AND METHODS Over a two-year period, we aim to perform studies to validate the performance of both of these MR oxygenation imaging protocols in normal subjects exposed to inspired gas challenges that will alter the global brain oxygenation. We will then apply the best of these two techniques to a cohort of acute ischemic stroke patients to determine the performance of the oxygenation-diffusion (O2- DWI) mismatch as a potential improved substitute for the traditional DWI-PWI mismatch. SIGNIFICANCE We believe successful attainment of these aims will markedly improve acute stroke care by validating a non-invasive MRI-based method to assess tissue oxygenation. We believe that there will be wide-reaching benefits to the development of a robust MR oxygenation method in a wide range of other neurological diseases, including carotid steno-occlusive disease, brain tumors, multiple sclerosis, and neurodegenerative disease.