Correction of phase effects produced by eddy currents in solvent suppressed 1H‐CSI

Abstract

Accurate phasing of MRS spectra is often difficult unless time varying phase effects produced by gradient‐induced eddy currents that persist during data acquisition are eliminated. This effect is particularly problematic in 1H‐CSI spectra where frequency shifts produced by static field inhomogeneity and phase shifts produced by eddy currents combine. In this paper we present a method that corrects both shifts and eliminates manual phasing of individual CSI spectra typically required to recover a pure absorption line shape. The method uses a time domain phase correction derived from the ambient water signal acquired under identical conditions (i.e., acquisition parameters, gradient sequence) as the solvent‐sup pressed CSI data. Results from CSI experiments on phantoms and in vivo solvent suppressed 1H‐CSI spectra from normal human brain are presented demonstrating the capabilities of the technique. Copyright © 1993 Wiley‐Liss, Inc., A Wiley Company