Variable-Field Nuclear Magnetic Relaxometer

项目总结/摘要 MGH成像创新研究所（i3）要求核磁弛豫测量仪器， 在0.00023T和3.0T之间的场循环能力。弛豫计是一种测量原子核 样品的磁弛豫时间（T1，T2）作为施加磁场的函数。弛豫 在给定场强下进行的测量用于筛选功效小分子， 用于磁共振成像（MRI）的高分子探针。弛豫测量 作为变化的场和/或温度的函数来表征分子机制， 支持核磁弛豫增强，从而指导分子策略探针优化。 弛豫测定法也可用于询问生物分子与顺磁离子之间的相互作用， 表征和量化组织中的分子水平病理变化，或更好地了解生理学 血液或组织中的波动可能影响MRI扫描中的信号。 MGH目前没有功能性弛豫仪。直到最近，MGH的研究人员才筛选出 新开发的松弛剂使用两个固定场弛豫仪在0.47T和1.4T的功能之一。 然而，这两项文书都已有20多年的历史，不再运作。弛豫测量 偶尔可以使用MGH Martinos中心的MRI扫描仪进行，但扫描仪严重 预订成像研究，研究人员的收费为每小时655美元和300美元，用于临床和非临床研究。 扫描仪和目前的实验配置对样品温度的控制很差。测量 偶尔也可以使用用于NMR光谱的11.7T或14.1T垂直孔磁体进行 在查尔斯敦海军造船厂这些光谱仪能够进行可变温度记录， 与临床MR扫描仪和绝大多数非临床MR扫描仪相比， MR扫描仪，从而降低了为筛选MR成像探头功效而执行的测量的相关性。 所要求的仪器将（1）取代严重依赖的0.47T和1.4T弛豫计 筛选新的磁共振成像探头，（2）提供了一个独特的和非常强大的实验资源 它可以用来研究控制核磁弛豫的分子机制， 探针优化，询问生物系统中生物分子的结构，动力学和物种形成， 促进体模工程测试并行开发的新MRI扫描仪技术， 生理变化（pO 2、红细胞压积）和MR成像探针如何影响人类fMRI的定量模型 信号，并指导成像生物标志物的识别。

Project Summary/ Abstract The MGH Institute for Innovation in Imaging (i3) requests nuclear magnetic relaxometry instrumentation with field cycling capabilities between 0.00023T and 3.0T. A relaxometer is a device that measures the nuclear magnetic relaxation times (T1, T2) of samples as a function of applied magnetic field. Relaxometry measurements performed at a given field strength are used to screen the efficacy small molecule and macromolecule probes that are used in magnetic resonance imaging (MRI). Relaxometry measurements performed as a function of varied field and/ or temperature us to characterize the molecular mechanisms that underpin nuclear magnetic relaxation enhancement and thus guide molecular strategies to probe optimization. Relaxometry can also be used to interrogate interactions between biomolecules and paramagnetic ions, to characterize and quantify molecular level pathologic changes in tissue, or to better understand how physiological fluctuations in blood or tissue may influence signal in an MRI scan. There is currently no functioning relaxometer at MGH. Until recently, MGH researchers screened the efficacy of newly developed relaxation agents using one of two fixed-field relaxometers functioning at 0.47T and 1.4T. However, both instruments are over 20 years old and are no longer operational. Relaxometry measurements can occasionally be performed using MRI scanners at the MGH Martinos Center, but the scanners are heavily booked for imaging studies, researchers are billed $655 and $300 per hour for the use of clinical and non-clinical scanners, and current experimental configuration provide poor control over sample temperature. Measurements can also occasionally be performed using the 11.7T or 14.1T vertical bore magnets used for NMR spectroscopy in the Charlestown Navy Yard. These spectrometers enable variable temperature recordings but these spectrometers operate at very high field compared to clinical MR scanners and the vast majority of non-clinical MR scanners, thus diminishing the relevance of measurements performed to screen MR imaging probe efficacy. The requested instrumentation will (1) replace the 0.47T and 1.4T relaxometers that have been heavily relied upon to screen new MR imaging probes, and (2) provide a unique and extremely powerful experimental resource that can be applied to interrogate molecular mechanisms that govern nuclear magnetic relaxation, guide imaging probe optimization, interrogate structure, dynamics, and speciation of biomolecules in biological systems, to facilitate engineering of phantoms to test on new MRI scanner technology being developed in parallel, to develop quantitative models of how physiologic changes (pO2, hematocrit) and MR imaging probes impact human fMRI signals, and to guide identification of imaging biomarkers.