The benefits of increasing spatial resolution as a means of reducing artifacts due to field inhomogeneities

Abstract

All users of NMR equipment are familiar with the desirability of achieving as high a quality of field as possible. On the other hand, it is easy to forget that the field quality of relevance in both imaging and spectroscopy is that over individual voxels, and not the whole volume. This note demonstrates in practice how performance in poor fields is improved substantially by reducing voxel size (or increasing spatial resolution), offering a potential alternative to additional shimming under appropriate circumstances. It argues that the best criterion for assessing magnet quality in spatially localized systems is the maximum field error gradient in the volume of usable field, rather than the maximum deviation in the field.