MRI Susceptometry for Measuring Hemoglobin Saturation In Vivo

用于测量体内血红蛋白饱和度的 MRI 敏感度测定法

• 批准号: 7615125
• 负责人: Felix W Wehrli
• 金额: $ 19.69万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7615125
• 关键词: Address; Arteries; Blood; Blood Circulation; Blood Gas Analysis; Blood Volume; Brain; Caliber; Calibration; Cardiopulmonary Bypass; Carotid Arteries; Chronic Obstructive Airway Disease; Clinical; Congenital Heart Defects; Development; Diabetes Mellitus; Disease; Equation; Error Sources; Erythrocytes; Forearm; Hematocrit procedure; Hemodilution; Hemoglobin; Human; Human Volunteers; Hypercapnia; Hypoxemia; Hypoxia; Image; Individual; Ischemia; Kidney; Laboratories; Length; Limb structure; Liver; Magnetic Resonance; Magnetic Resonance Imaging; Magnetism; Maps; Measurement; Measures; Methodology; Methods; Modeling; Near-Infrared Spectroscopy; Noise; Optics; Organ; Oxygen; Oxygen saturation measurement; Peripheral; Peripheral Vascular Diseases; Phase; Physiologic pulse; Physiological; Predisposition; Process; Protons; Pump; Radiation; Relative (related person); Relaxation; Reproducibility; Research; Resolution; Rest; Shapes; Signal Transduction; Solutions; Source; Stimulus; Structure of jugular vein; Structure of popliteal artery; Techniques; Technology; Testing; Time; Tissues; Training; Validation; Variant; Veins; Venous; Water; Whole Blood; Work; base; deoxyhemoglobin; design; human subject; in vivo; magnetic field; public health relevance; response; tissue oxygenation; transmission process; water diffusion

DESCRIPTION (provided by applicant): Changes in blood oxygen saturation are of pivotal importance in a multitude of clinical conditions, including peripheral vascular disease, congenital cardiac abnormalities, diabetes, hypoxemias such as in chronic obstructive pulmonary disease, and ischemic disease of various organs. Current noninvasive methods are based on near infrared spectroscopy (NIRS) which can measure tissue oxygen saturation. These methods, however, are hampered by poor resolution. Further, the relative opacity of mammalian tissue to optical radiation precludes measurements of deep-lying tissues, and the method is unable to target specific arteries and veins. Quantitative MRI resting on a measurement of blood T2 has proven useful but the method requires extensive calibration and its implementation is involved. In this project we propose the development, implementation and validation of a new method for measuring blood oxygen saturation that involves virtually no calibration, allows for rapid and reliable measurement of hemoglobin saturation in arteries and veins at high spatial resolution. The method's principle is based on a measurement of the bulk magnetic susceptibility of blood, which is a function of the blood's hemoglobin oxygen saturation. In a vessel that can be modeled as a cylinder whose diameter is much less than its length, the demagnetizing field has a simple closed-form solution. From the intra-to-extravascular induced magnetic field difference obtained by phase mapping, the blood's volume susceptibility can be computed and thus hemoglobin saturation obtained. We show in preliminary work the method's feasibility and demonstrate its ability to quantify the response to a physiologic stimulus in the peripheral circulation. In four specific aims we propose to further develop and evaluate the image acquisition and processing methodology and quantify potential sources of error, both computationally and experimentally. We plan to validate the method in human subjects in models of peripheral limb ischemia and compare the baseline and post-occlusion hyperemic response with those of blood gas analysis as well as with tissue oxygen saturation measured by NIRS. PUBLIC HEALTH RELEVANCE: Venous and arterial oxygen saturation are among the most important physiological parameters. Currently, there exist no robust noninvasive techniques for measuring hemoglobin saturation in individual deep-lying vessels. Magnetic resonance susceptometry has substantial promise to fill this gap.

描述（由申请人提供）：血氧饱和度的变化在许多临床疾病中具有关键的重要性，包括周围血管疾病、先天性心脏异常、糖尿病、低氧血症（如慢性阻塞性肺疾病）和各种器官的缺血性疾病。目前的非侵入性方法是基于近红外光谱（NIRS）来测量组织氧饱和度。然而，这些方法受到分辨率差的阻碍。此外，哺乳动物组织对光辐射的相对不透明妨碍了对深层组织的测量，并且该方法无法针对特定的动脉和静脉。基于血液T2测量的定量MRI已被证明是有用的，但该方法需要大量校准并且涉及其实施。在这个项目中，我们提出了一种测量血氧饱和度的新方法的开发，实施和验证，该方法几乎不需要校准，可以快速可靠地测量动脉和静脉中的血红蛋白饱和度，具有高空间分辨率。该方法的原理是基于测量血液的整体磁化率，这是血液血红蛋白氧饱和度的函数。在一个直径远小于其长度的圆柱体中，退磁场有一个简单的封闭解。通过相位映射得到的血管内外诱导磁场差，可以计算出血液的体积敏感性，从而得到血红蛋白饱和度。我们在初步工作中展示了该方法的可行性，并证明了其量化外周循环对生理刺激的反应的能力。在四个具体目标中，我们建议进一步发展和评估图像采集和处理方法，并在计算和实验上量化潜在的误差来源。我们计划在人体外周肢体缺血模型中验证该方法，并将基线和闭塞后充血反应与血气分析以及近红外光谱测量的组织氧饱和度进行比较。公共卫生相关性：静脉和动脉氧饱和度是最重要的生理参数之一。目前，还没有可靠的无创技术来测量单个深层血管中的血红蛋白饱和度。磁共振电纳法有望填补这一空白。

项目成果

Simultaneous mapping of temporally-resolved blood flow velocity and oxygenation in femoral artery and vein during reactive hyperemia.

• DOI: 10.1186/1532-429x-13-66
• 发表时间: 2011-10-28
• 期刊: Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
• 作者: Langham MC;Wehrli FW
• 通讯作者: Wehrli FW

Investigating the magnetic susceptibility properties of fresh human blood for noninvasive oxygen saturation quantification.

• DOI: 10.1002/mrm.23282
• 发表时间: 2012-09
• 期刊: MAGNETIC RESONANCE IN MEDICINE
• 影响因子: 3.3
• 作者: Jain, Varsha;Abdulmalik, Osheiza;Propert, Kathleen Joy;Wehrli, Felix W.
• 通讯作者: Wehrli, Felix W.