CHARACTERIZATION OF PARAMAGNETIC EFFECTS OF MOLECULAR OXYGEN

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 在由血氧水平依赖性（BOLD）效应调节的高氧造影剂研究中，高氧通常是T2* 加权图像中纯粹的血管内阳性造影剂，并且不是由于BOLD造影剂引起的效应小到可以忽略。 在本项目中，我们重新评估了这一假设，目的是在T2* 加权高氧对比研究中表征非BOLD效应。 氧气作为血管内造影剂的质量不仅取决于其对基础生理学的最小影响，还取决于其不是由于脱氧血红蛋白稀释引起的最小舒张效应。 尽管已知溶解在血液中的分子氧具有相对弱的T2和T1弛豫率，但已显示分子氧作为体液中的T1造影剂是有效的，具有将显著浓度的分子氧快速洗入到这些组织中。 另一个重要的影响是由于上呼吸道中顺磁性气态氧的影响而破坏大脑额叶中的静磁场（B 0），这在人脑的高氧对比研究中尚未得到表征。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In hyperoxic contrast studies modulated by the blood oxygenation level-dependent (BOLD) effect, it is often that hyperoxia is a purely intravascular, positive contrast agent in T2*-weighted images, and the effects that are not due to BOLD contrast are small enough to be ignored. In this project, we reevaluated this assumption, with the goal of characterizing non-BOLD effects in T2*-weighted hyperoxic contrast studies. The quality of oxygen as an intravascular contrast agent depends not only on its minimal effects on the underlying physiology, but also on its minimal relaxation effects not due to the dilution of deoxyhemoglobin. Although it is known that molecular oxygen dissolved in the blood has a relatively weak T2 and T1 relaxivities molecular oxygen has been shown to be effective as a T1 contrast agent in body fluids, with a fast wash-in of a significant concentration of molecular oxygen into these tissues. Another important effect is the disruption of the static magnetic field (B0) in the frontal lobes of the brain due to the influence of paramagnetic gaseous oxygen in the upper airway, which has not yet been characterized in hyperoxic contrast studies of the human brain.