Phase Navigators for Localized MR Spectroscopy Using Water Suppression Cycling

Thomas Ernst¹, Jikun Li²

Magnetic resonance spectroscopy (MRS) is sensitive to subject motion, in part due to phase and frequency variations during movements. A novel water-suppression cycling scheme was developed that alternates between under-suppressed and over-suppressed residual water, and allows 1) phase and frequency correction of individual FIDs using the residual water signal, 2) restoration of signal losses due to incoherent averaging, and 3) near-complete attenuation of residual water. It is demonstrated that phase-correction, using the residual (cycled) water signal, can restore spectra with very poor signal-to-noise ratio (SNR) and line-width induced by subject motion.