Novel RF Coils for In Vivo MR Applications at High Field

描述(由申请人提供)： 高场磁共振成像(MRI)和光谱学(MRS)的技术发展已经加快，因为高灵敏度的优势显著地提高了人类应用的能力和可靠性。这一进步进一步被高场下可用于功能磁共振成像和临床诊断的独特图像对比度所刺激。然而，要充分实现这一进步，必须解决许多挑战。与高场相关的主要问题是射频线圈的设计困难，以及当射频波长接近射频线圈的尺寸时射频线圈的复杂磁场(B1)。其结果是：(1)线圈品质因数和核磁共振灵敏度严重下降；(2)设计高工作频率的大尺寸线圈受到限制；(3)B1场分布复杂，MRI强度难以量化。这些复杂情况需要创新的策略来克服与高场下的射频线圈相关的问题。与宾夕法尼亚州立大学的杨博士合作，在这份拨款申请中提出了一个全面的项目，以应对高场射频工程挑战。主要目标将集中在(I)利用基于微带传输线(MTL)方法的创新设计来开发一系列用于人类和动物研究的坚固而高效的高场射频线圈，(Ii)利用基于射频场建模和MRI测量的计算机模拟来研究高场下人头部的B1场行为，并研究B1场对MRI量化的影响，(Iii)进行一系列研究，以系统地评估所提出的线圈与其他现有线圈的比较。这项研究的成功成果将为高场射频线圈设计提供一种替代的和令人满意的解决方案，并导致用于活体磁共振应用的高场射频线圈工程的重大技术进步。

DESCRIPTION (provided by applicant): Technical developments in high-field magnetic resonance imaging (MRI) and spectroscopy (MRS) have been accelerated because of the advantage of high sensitivity that significantly improves the capability and reliability for human applications. This advancement is further stimulated by the unique image contrasts available at high fields for fMRI and clinical diagnosis. However, to fully realize the advancement, many challenges must be resolved. Major problems associated with high fields are the difficulty of radiofrequency (RF) coil designs and the complex magnetic fields (B1) of RF coil when the wavelength of RF wave approaches RF coil's size. They result in (i) severe degradation of coil quality factor and NMR sensitivity, (ii) limitation for designing large size coils with high operating frequency and (iii) complex B1 field distributions and difficulty for quantifying MRI intensity. These complications necessitate innovative strategies to overcome the problems associated with RF coils at high fields. In collaboration with Dr. Yang from Penn State University, a comprehensive project is proposed in this grant application for addressing the RF engineering challenges at high fields. The major goals will focus on (i) developing a host of robust and efficient high-field RF coils for human and animal studies using an innovative design based on the microstrip transmission line (MTL) approach, (ii) studying the B1 field behavior in human head at high fields using computer simulation based on RF field modeling and MRI measurements, and studying the implications of B1 field on MRI quantification, (iii) conducting a series of study for systematically evaluating the proposed coils in comparison with other existing coils. Successful outcomes from this research will provide an alternative and satisfactory solution of RF coil design at high fields and result in significant technological advances in high-field RF coil engineering for in vivo MR applications.