基于绝热射频脉冲的磁共振定域谱新技术及其生物医学应用

Localized magnetic resonance spectroscopy (MRS) has been widely used in the biomedical research field.　So far it is the only noninvasive technique that is able to detect biological metabolites of in vivo and quantify different chemical compounds. Therefore, MRS has great potential application in clinical medicine. However, the accuracy of quantification and the biomedical application of MRS are greatly restricted and challenged by the shortcomings of MRS, for instance, chemical shift displacement, sensibility to B1 field inhomogeneities, inaccuracy of voxel localization, low resolution and low SNR, signal overlaps and line-broadening due to magnetic susceptibilities of various tissues of in vivo, etc. Overcoming these disadvantages is the hot topic in the in vivo MRS field. In this project, we will focus on the following work: (1) Design new adiabatic RF pulse sequences to improve the accuracy of voxel localization, suppress chemical shift displacement and spatially dependent J-evolution; (2) Combine the adiabatic technique with inter-molecular multi-quantum coherence and fast acquisition techniques (such as spatially encoded fast method, etc.) and multi-dimensional high-resolution MRS to reduce line-broadening and scan time, and improve signal-to-noise ratio (SNR); (3) Apply the new methods to some typical biomedical systems, and expand its application field.

磁共振定域波谱(MRS) 在生物医学研究领域内的应用非常广泛，是迄今为止惟一能对活体组织代谢进行无创检测的一种手段，并可对机体内多种不同化合物进行相对定量分析，具有重大的临床医学应用前景。然而传统MRS的一些缺点，如化学位移偏移，对射频场不均匀性敏感，体素定位不准，分辨率和信噪比低，采集时间长，谱峰复杂、密集且多有重叠，生物组织间的磁化率差异导致的谱线增宽等问题，使得MRS的可靠定量及它的生物和临床应用受到极大挑战。克服MRS的不足，是活体磁共振领域最新前沿和热点问题之一。本课题拟开展如下研究：（1）设计新的绝热脉冲序列以改善体素定位准确度，压制化学位移偏移及空间相关的J偶合演化问题；（2）结合分子间多量子相干和快速采集（如空间编码等）技术发展快速多维高分辨MRS谱以减小线宽，缩短采样时间，改善信噪比；（3）将所建立的绝热脉冲技术应用于生物医学体系，以扩展其应用领域。