Overhauser Enhanced Magnetic Resonance Imaging (OMRI)

项目2：Overhauser增强磁共振成像。(OMRI)总结：a)Overhauser增强MRI：在这项技术中，组织水的极化是在非常低的磁场下原位完成的。早期的研究使用的是扫描仪，这是EPR(用于超极化)和MR成像(用于检测)的组合，使用的造影剂松弛特性与pO2线性相关。这些研究证明了这种技术的定量pO2成像能力。我们正在探索OMRI在研究肿瘤生理学方面的更多应用，利用动态核极化过程的固有优势。磁共振动脉自旋标记是一种广泛应用于检查血流相关问题的技术。这种方法已经被适应于OMRI，其中动脉中的一部分自旋被准备用于在被灌流的组织上游区域中进行检测。在MRI中，OMRI相对于ASL的固有优势是OMRI的可用动态范围大于MRI。除了用OMRI检测顺磁性物种外，我们还直接将这些探针用作磁共振成像中的T1对比分子，并在体内成像它们的空间分布和药代动力学行为。B)使用动态核极化的新陈代谢成像：通常，尽管MRI的固有灵敏度较低，但通过探测组织水质子的磁性，通常可以成功地提供解剖图像。这一成功的原因是组织中有丰富的水(&gt；45M)，在所有的核自旋中，探测来自水质子的信号比所有其他原子核相对容易。然而，由于13C的弱磁矩和低水平的代谢物(10 100 MM)，对其他代谢物，特别是体内含碳的有机分子的成像是具有挑战性的。使用13C标记的丙酮酸和超极化等外源示踪剂，可以通过13C MRI对这些分子进行成像，还可以监测该分子对其他代谢物的代谢分解，并根据其特征核磁共振谱对其进行鉴定。由于丙酮酸处于细胞能量学的关键节点，使用这项技术，可以使用核磁共振对组织进行生化表征。我们已经与GE Healthcare签订了CRADA协议，并在MRI设施中安装了超极化设备。

Project 2: Overhauser enhanced Magnetic Resonance Imaging. (OMRI) Summary: a) Overhauser enhanced MRI: In this technique, the polarization of the tissue water is accomplished in situ at very low magnetic fields. Earlier studies used a scanner, which is a combination of EPR (For hyperpolarizing) and MR imaging (for detection) using a contrast agent whose relaxation properties are linearly dependent on pO2. These studies demonstrated the quantitative pO2 imaging capabilities of this technique. We are exploring additional applications for OMRI in studying tumor physiology taking advantage of the inherent advantage of the process of dynamic nuclear polarization. Arterial spin labeling in MRI is a widely used technique in examining issues related to blood flow. This method has been adapted to OMRI where a portion of spins in an artery are prepared for detection in a region upstream of the tissue being perfused. The inherent advantage of OMRI over ASL in MRI is the available dynamic range in OMRI being greater than in MRI. In addition to detecting the paramagnetic species by OMRI, we are using these probes directly as T1 contrasting molecules in MRI and imaging their spatial distribution and their pharmacokinetic behavior in vivo. b) Metabolic Imaging using Dynamic Nuclear Polarization: Usually, MRI, in spite of the low intrinsic sensitivity, can successfully provide anatomic images by probing the magnetic properties if tissue water protons. The reason for this success is that there is abundant water (> 45 M) in tissue and, of all the nuclear spins, detecting the signals from water protons are relatively easier compared to all other nuclei. However, imaging other metabolites, especially carbon containing organic molecules in vivo is challenging, because of the weak magnetic moments of 13C and the low levels of metabolites (10 100 mM). Using exogenous tracers such as 13C labeled pyruvate and hyperpolarization, it is possible to image these molecules by 13C MRI and also monitor the metabolic breakdown of this molecule to other metabolites and identify them based on their characteristic NMR spectra. Since pyruvate is at a crucial junction of cellular energetics, it is possible, using this technique, to biochemically characterize the tissues using MRI. We have entered into a CRADA with GE Healthcare and installing the apparatus for hyperpolarization at the MRI facility.