Characterizing MRI parameters of iron-loaded tissues

描述（由申请人提供）： 该项目的总体目标是定量了解组织铁水平和核磁共振（NMR）特性之间的关系，以开发一种严格测量大脑，肝脏和其他器官中铁的方法。铁是一种生理上至关重要的物质，但它也可能是有毒的，并与各种组织中的许多病理状态有关。正如最近NIDDK研讨会的报告中所总结的那样，目前唯一建立的，用于非侵入性测量组织铁储存的校准方法是使用超导量子干涉器件（SQUID）磁力计的生物磁测磁法，但成本，复杂性和技术要求限制了这种技术的使用。许多以前的研究表明，磁共振成像（MRI）可以检测铁负荷，但没有明确的协议已经建立，以准确地测量组织中的铁含量。虽然NMR可以容易地检测取决于组织的铁含量的各种信号参数，但是这些参数（例如T1、T2、T2*、T2 ′、δ/ω）对所储存的铁的浓度和形式的确切依赖性是复杂和不清楚的。这个问题只能通过将铁代谢的研究与基本核弛豫机制的研究和先进的MRI测量方案的发展相结合来解决。我们在范德比尔特的团队是唯一有资格采用这种方法的。我们建议联合收割机的铁过载，先进的核磁共振技术，高分辨率SQUID磁化率成像的动物模型的研究。这些实验与计算机模拟相结合，将允许对来自个体动物的生物磁性和NMR数据进行详细的定量比较，其组织铁含量可以在每次实验结束时定量测定

DESCRIPTION (provided by applicant): The overall aims of this project are to understand quantitatively the relationships between tissue iron levels and nuclear magnetic resonance (NMR) properties in order to develop a method for rigorously measuring iron in the brain, liver, and other organs. Iron is a physiologically vital substance, but it also can be toxic and has been associated with numerous pathological states in various tissues. As summarized in the report of a recent NIDDK workshop, the only established, calibrated method for non-invasive measurement of tissue iron stores is currently biomagnetic susceptometry using Superconducting Quantum Interference Device (SQUID) magnetometers, but the cost, complexity, and technical demands limit access to this technique. Many previous studies have indicated that magnetic resonance imaging (MRI) can detect iron loading, but no clear protocol has been established to measure iron content in tissue accurately. While NMR can readily detect a variety of signal parameters that depend upon the iron content of tissue, the exact dependence of these parameters (e.g. T1, T2, T2*, T2', delta/omega on the concentration and form of the stored iron is complex and unclear. This problem can be addressed only by combining studies of iron metabolism with studies of fundamental nuclear relaxation mechanisms and the development of advanced MRI measurement protocols. Our group at Vanderbilt is uniquely qualified for such an approach. We propose to combine the study of an animal model of iron overload, advanced NMR techniques, and high-resolution SQUID susceptibility imaging. These experiments, in combination with computer simulations, will allow the detailed, quantitative comparison of biomagnetic and NMR data from individual animals whose tissue iron content can be determined quantitatively at the end of each experiment