利用主动式回馈场的磁共振成像研究  

Studies of Magnetic Resonance Imaging with Active Feedback RF Field

作　　者：黄圣言[1] 林永雅 黄良平[3,4] 

机构地区：[1]中正大学化学暨生物化学系 [2]Department of Chemistry and Biochemistry,University of California,Los Angeles [3]台湾大学化学系 [4]中研院原子与分子科学研究所

出　　处：《波谱学杂志》2010年第3期409-416,共8页Chinese Journal of Magnetic Resonance

摘　　要：磁共振成像在现今临床医学诊断上占有相当重要的地位.如何增强成像对比度是磁共振成像研究领域中极为重要的课题.传统成像中利用磁共振性质的差异性来获得成像对比度,然而当这些性质的差异性小时,即使经过时间演化,还是难以得到可视的对比度.为了解决此问题,辐射阻尼是其中一个可能的方案.之前的研究显示,辐射阻尼对极小频率差亦能够在短时间的演化下得到相当强的对比度.然而辐射阻尼的产生需要高敏感度的射频线圈等限制.该研究将介绍如何利用外加的线路,模拟辐射阻尼现象,进而控制自旋动态,以达到增强成像对比度并进一步设计新的磁共振成像方式.Magnetic resonance imaging （MRI） now plays a significant role in clinical medical diagnosis.How to increase the image contrast has been of crucial importance in the field of MRI.Traditionally,contrast is generated by the differences in the magnetic resonance properties between different positions.However,when these differences are small,the desired contrast may not be achievable even if a long evolution time is used.Radiation damping is one of proposed approaches that may give a solution to this problem.Our previously published results indicate that radiation damping can induce a large contrast for small frequency differences even in a short period of time.Nevertheless,radiation damping requires a highly sensitive RF coil and must meet other conditions for it to be practically useful.The paper explains how to generate radiation damping by using a purposefully designed external circuit and how to control the spin dynamics so that the contrast is increased and a novel type of MRI is introduced.

关 键 词：磁共振成像(MRI) 自旋动力学 辐射阻尼 主动回馈 

分 类 号：R445.2[医药卫生—影像医学与核医学]