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：在该技术中，组织水的极化在非常低的磁场下原位完成。早期的研究使用扫描仪，它是EPR（用于超极化）和MR成像（用于检测）的组合，使用造影剂，其弛豫特性线性依赖于pO 2。这些研究证明了该技术的定量pO 2成像能力。我们正在探索OMRI在研究肿瘤生理学中的其他应用，利用动态核极化过程的固有优势。MRI中的动脉自旋标记是一种广泛使用的技术，用于检查与血流相关的问题。该方法已经被适配于OMRI，其中动脉中的自旋的一部分被准备用于在正被灌注的组织的上游区域中的检测。在MRI中，OMRI相对于ASL的固有优势是OMRI中的可用动态范围大于MRI。除了通过OMRI检测顺磁性物质外，我们还直接使用这些探针作为MRI中的T1对比分子，并对其空间分布和体内药代动力学行为进行成像。B）使用动态核极化的代谢成像：通常，MRI尽管固有灵敏度低，但可以通过探测组织水质子的磁特性来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（> 45 M），并且在所有核自旋中，与所有其他核相比，检测来自水质子的信号相对更容易。然而，成像其他代谢物，特别是含碳的有机分子在体内是具有挑战性的，因为弱磁矩的13 C和低水平的代谢物（10 - 100 mM）。使用外源性示踪剂，如13 C标记的丙酮酸和超极化，可以通过13 C MRI对这些分子进行成像，还可以监测该分子代谢分解为其他代谢物，并基于其特征NMR光谱对其进行鉴定。由于丙酮酸处于细胞能量学的关键节点，因此可以使用这种技术，使用MRI对组织进行生物化学表征。我们已与GE Healthcare达成CRADA，并在MRI机构安装了超极化设备。

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.