Ultra-high field MRSI (7T and Beyond)

Human magnetic resonance imaging (MRI) and spectroscopy (MRS) systems operating at 7 T are becoming quite common in major academic medical systems around the world, with more than 40 installations as of 2013. Advantages of MRS at higher fields include improved signal-to-noise ratios and spectral resolution, which translate into the ability to measure more compounds with better precision. Some of the greatest improvements are for overlapping, coupled spin systems such as glutamate and glutamine, which are hard to separate and measure accurately at lower field strengths. However, various technical challenges need to be overcome at higher field strengths in order to fully realize the expected improvements. This chapter reviews some of the problems associated with high-field MRS and their solutions, and also discusses some of the early studies of disease pathology using 7 T MRS. Since to date most 7 T MRS and magnetic resonance spectroscopic imaging (MRSI) studies have focused on technical issues, clinical applications of this methodology are still in the early stages of development.