Infrastructure and Applications of Hyperpolarized 129Xe

超极化129Xe的基础设施和应用

• 批准号: 6647546
• 负责人: SAMUEL PATZ
• 金额: $ 61.83万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6647546
• 关键词: biological models; clinical research; diffusion; high throughput technology; human subject; laboratory rabbit; lasers; lung imaging /visualization /scanning; magnetic resonance imaging; optical polarization; phase change; radiowave radiation; rubidium; technology /technique development; xenon

DESCRIPTION (provided by applicant): The field of 3He hyperpolarized gas MRI has seen great advances recently. This is not the case for MRI with 129Xe gas. The principal reason for this disparity is the limited supply of highly polarized 129Xe gas available for studies. For example, present day polarization apparatus for 129Xe MRI typically provide less than 1/2 liter per hour at 10% polarization. Members of our collaboration have recently demonstrated a revolutionary new polarization apparatus that operates at lower xenon pressures and higher flow velocities than existing state-of-the-art. Their results have confirmed that higher xenon polarizations can be obtained at lower operating pressures with fixed gas production rate. Thus the purpose of this BRP is to use this exciting new source of highly polarized and high throughput ]29Xe gas to explore its potential to provide quantitative information on lung structure and function. While both 129Xe and 3He provide excellent ventilation maps, 129Xe is unique in 3 ways: (1) a high solubililty in tissue, (2) a large chemical shift of the tissue relative to the gas NMR frequency, and (3) a -25 times smaller diffusion constant compared to 3He. Properties 1 and 2 permit measurement of exchange of xenon gas into tissue. We will exploit this to determine the regional surface area to volume ratio, a microstructure parameter closely related to gas exchange efficiency. A second quantity, the diffusivity of 129Xe gas in the acinus, will also be measured as a function of the time allowed for diffusion to evolve. Because of Property 3, the short time 129Xe diffusion distance is smaller than possible with 3He, probing dimensions comparable to the average alveolar pore size. At long times, D(t) gives additional information about the lung microstructure, specifically the connectivity (or tortuosity) between adjacent acinar structures. Tortuosity may be an important predictor for susceptibility to airborne particulates. We propose measurements of 129Xe D(t) to establish its value as a "fingerprint" of lung microstructure. The team of researchers assembled for this proposal have been closely collaborating for over 6 years and have developed particular expertise in both polarizing and exploiting the unique features of 129Xe. A polarizer will be built, sited and supported at Brigham and Women's Hospital. Animal and human studies are proposed to demonstrate the structural and functional information 129Xe MRI can provide.

描述（由申请人提供）： 3 He超极化气体磁共振成像技术近年来取得了很大进展。对于使用129氚气体的MRI，情况并非如此。造成这种差异的主要原因是可用于研究的高度极化的129氚气体供应有限。例如，目前用于129 μ m MRI的极化设备通常在10%极化下提供小于1/2升/小时。我们合作的成员最近展示了一种革命性的新偏振装置，该装置在较低的氙气压力和较高的流速下工作，比现有的最先进的。他们的结果证实，在较低的工作压力下，可以获得较高的氙气偏振，固定的气体生产率。因此，本BRP的目的是使用这种令人兴奋的高度极化和高通量的[29] O2气体的新来源来探索其提供肺结构和功能的定量信息的潜力。虽然129 He和3 He都提供了出色的通气图，但129 He在3个方面是独特的：（1）在组织中的高溶解度，（2）相对于气体NMR频率的组织的大化学位移，以及（3）与3 He相比，扩散常数小约25倍。特性1和2允许测量氙气交换到组织中。我们将利用这一点来确定区域表面积与体积比，一个与气体交换效率密切相关的微观结构参数。第二个量，129氚气体在腺泡中的扩散率，也将被测量为扩散时间的函数。由于性质3，短时间129 He扩散距离小于3 He可能的扩散距离，探测尺寸与平均肺泡孔径相当。在长时间内，D（t）给出了关于肺微观结构的额外信息，特别是相邻腺泡结构之间的连接性（或弯曲度）。弯曲度可能是对空气颗粒物敏感性的一个重要预测因子。我们建议测量129 μ D（t），以确定其值作为肺微观结构的“指纹”。为这项提议而组建的研究团队已经密切合作了6年多，并在极化和利用129 π的独特功能方面积累了特殊的专业知识。一个偏振器将在布里格姆妇女医院建造、安装和支持。动物和人类的研究，建议证明129 MRI可以提供的结构和功能信息。