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The three goals of this paper are: 1) to evaluate the improvements in technology for increasing magnetic flux density (magnetic field) to 14T in the next few years and eventually to 20T; 2) to highlight neuroscience opportunities enabled by these advances; and, 3) to evaluate the physiological and biophysical effects associated with MRI at very high performance levels. Substantial recent advances in magnet technology including superconductor developments enable neuroscience goals that are not obtainable at contemporary magnetic fields. Ten areas of brain neuroscience include potential improvements in resolution for functional MRI(BOLD), diffusion weighted MRI, tractography, susceptibility weighted MR, neuronal architecture patterns related to human behavior, proton spectroscopy of small brain biochemicals, chemical exchange saturation transfer (CEST), dynamic contrast enhanced MRI, brain energy metabolism using 13C, 17O, and 31P; and brain electrolyte physiology using 23Na, 35Cl, and 39K. Physiological phenomena and safety aspects include: absorbed RF power, acoustic sound pressure levels, induced electric fields, Lorentz forces, magnetohydrodynamic forces, and biophysical phenomena in cells and tissues. Where feasible, effects are quantified for magnetic fields beyond 7T with the conclusion that there are no foreseen barriers either in the technical or human safety aspects of brain MRI and MRS at fields up to 20T. This conclusion is conditioned on results of recommended experiments to verify the predicted level of physiological effects beyond 9.4T. This technology is predicted to enable quantification of biochemical components of the functioning brain not detectable heretofore.

Resistive and resistive-superconducting hybrid magnets can generate dc magnetic fields much higher than conventional superconducting NMR magnets but the field spatial homogeneity and temporal stability are usually not sufficient for high-resolution NMR experiments. Hardware and technique development addressing these issues are presented for high-resolution NMR at magnetic fields up to 40 T. Passive ferromagnetic shimming and magic-angle spinning are used effectively to reduce the broadening from inhomogeneous magnetic field. A phase correction technique based on simultaneous heteronuclear detection is developed to compensate magnetic field fluctuations to achieve high spectral resolution.