Quantitative MT imaging development and application

描述(由申请人提供)： 该项目的总体目标是开发和优化磁共振成像(MRI)技术，用于组织中与脑髓鞘表征特别相关的大分子含量和动力学的新的定量测量。申请人在以前的工作中已经证明，可以使用一种新的磁共振技术来量化生物系统中大分子和自由水质子池的大小，并提供这些不同组织亚成分之间的磁化转移(MT)速率常数的定量测量。这项拟议的研究将进一步发展和优化这一技术，将该技术与其他MT技术进行比较，并将最佳技术与多组分T2测量相结合，以研究白质和脱髓鞘病变中发生的水渗漏和交换率的变化。该项目的具体目标如下： *进一步开发选择性反转恢复(SIR)，并优化SIR和脉冲饱和技术，以实现定量测量新组织特性的速度、可靠性和准确性。 *将SIR与脉冲饱和度进行比较，并在模型生物聚合物的一系列测量中以已知标准验证这两种方法。 *评估生物聚合物和健康大鼠体内MT定量成像的优化方法。 *评估定量MT成像对组织学揭示的脱髓鞘、炎症和轴突丢失引起的脑实质变化的敏感性，为进一步开发MRI在多发性硬化症中的应用提供信息。

DESCRIPTION (provided by applicant): The overall goal of this project is to develop and optimize a magnetic resonance imaging (MRI) technique for novel quantitative measurements of the macromolecular content and dynamics in tissues with special relevance to the characterization of brain myelin. The applicant has demonstrated in previous work that a novel MRI technique can be used to quantify (he ralio of the sizes of macromolecular and free water proton pools in biological systems, and provide a quantitative measure of the magnetization transfer (MT) rate constant between these different tissue subcomponents. The proposed studies will further develop and optimize this technique, will compare this technique to other MT techniques, and \vll use the optimum technique in combination with multi-component T2 measurements to investigate the changes in water cempartmeritation and exchange rates that occur in white matter and demyelinated lesions. The specific aims of the project are as follows: * to further develop selective inversion recovery (SIR) and to optimize both SIR and the pulsed saturation technique for speed, reliability, and accuracy for quantitatively measuring novel tissue properties. * to compare SIR to pulsed saturation and to validate both these methods against a known standard in a series of measurements on model biopolymers. * to evaluate optimized methods of quantitative MT imaging in biopolymers and in vivo in healthy rats. * to evaluate the sensitivity of quantitative MT imaging to changes in brain matter due to demyelination, inflamation, and axonal loss as revealed by histology, producing information that will further develop applications of MRI in multiple sclerosis.