Correction of phase effects produced by eddy currents in solvent suppressed 1H-CSI.
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-suppressed 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.
Roebuck
J R
JR
Bioengineering Program, University of Michigan, Ann Arbor.
Hearshen
D O
DO
O'Donnell
M
M
Raidy
T
T
D000465:Algorithms; D001921:Brain / Q000378:metabolism; D005583:Fourier Analysis; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008961:Models, Structural; D012815:Signal Processing, Computer-Assisted