Radio Frequency Coil Design for Ultra High Field MRI

射频(RF)线圈是磁共振成像(MRI)系统的重要组成部分。由于人体内的射频磁场/组织在强磁场下的相互作用(&gt；=3T)，头部大小的体积线圈的传输轮廓显示出独特的模式，在大脑的中心具有相对较强的射频磁场B(1+)，这种中心增亮效应可以影响图像或光谱的定量和定性方面。由于组织-B(1+)场相互作用带来的不均匀性，在感兴趣的体积中发现了更麻烦的、建设性的和破坏性的B(1+)图案。我们研究计划的目标是设计RF线圈组件，使人体在7T时发射(B1+)和接收(B1-)场的均匀性最小化。 我们的磁共振成像系统可能是世界上最先进的发射和接收通道配置，这使我们处于有利地位，可以继续为新一代射频阵列线圈进行科学和工程设计。几家核磁共振制造商正在他们的系统上开发多发射射频功能，以帮助克服超高场磁共振扫描仪中人体受试者的射频均匀性，这是一个正在加紧开发的领域，全球有50多台7T及更高温度的人类核磁共振仪器，并以每年5-10个单位的速度增长。射频不均匀和功率沉积是更广泛采用这些系统的重要障碍，我们的研究具有强大的学术和工业潜力来缓解这些问题。

Radio Frequency (RF) coils are an essential component of magnetic resonance imaging (MRI) systems. Due to RF field/tissue interactions in the human body at high magnetic fields (>= 3 T) the transmit profile from head-sized volume coils shows a distinctive pattern with a relatively strong RF magnetic field B(1+) in the center of the brain, This centre brightening effect can affect both quantitative and qualitative aspects of the image or spectrum. Even more troubling, constructive and destructive B(1+) patterns are found throughout the volume of interest due to the in homogeneities brought about by tissue-B(1+) field interaction The objective of our research program is to design RF coil assemblies that minimize the transmit (B1+) and receive (B1-) field RF in homogeneities at 7 T in human subjects. Our MRI system is probably the most advanced configuration of transmit and receive channels in the world which makes us we well positioned to continue the science and engineering for a new generation of RF array coils. Several MRI manufacturers are developing multiple-transmit RF capabilities on their systems to help overcome the RF in homogeneities that occur in human subjects in ultra-high field MRI scanners, and this is an area of intense development with over 50 instruments for MRI of humans at 7 T and higher worldwide and a growth rate of 5-10 units a year. RF inhomogeneity and power deposition are significant barriers for the adoption of these systems more broadly and our research has strong academic and industrial potential to alleviate these problems.