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Abstract #5030

Motion-Induced Frequency and Shim Variations During Localized 1H MR Spectroscopy with Prospective Motion Correction

Brian Keating1, Thomas Ernst1

1Department of Medicine, John. A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States

Motion during brain 1H MR spectroscopy may cause susceptibility-induced changes in B0. We used a PRESS sequence with prospective motion correction (PMC) to quantify the effects of motion on center frequency and shim quality. Subjects performed x- and z-head rotations while the MRS voxel tracked head motion. The center frequency displays a linear dependence on both θx (0.01ppm/deg) and θz (0.002ppm/deg). The FWHM is approximately a quadratic function of the θx, but is largely independent of θz. Our results indicate that PMC requires real-time frequency and shim updates in order to recover high-quality spectra in the presence of subject motion.