High field localized proton spectroscopy in small volumes: greatly improved localization and shimming using shielded strong gradients

Abstract

The availability of shielded gradients facilitates accurate single-voxel localized spectroscopy. Exact localization (90−99%) of volumes as small as 2 × 2 × 2 mm is demonstrated using a modified stimulated echo sequence. Strong gradient pulses (up to 200 mT/m) are employed to clear the stimulated echo of unwanted magnetization, enabling superior (single-scan) shimming of the selected volume. In vivo and in vitro proton NMR results at 4.7 T are presented. © 1989 Academic Press, Inc.