Radio Frequency Coil Design for Ultra High Field MRI

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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.