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Correction of phase effects produced by eddy currents in solvent suppressed 1 H‐CSI
Author(s) -
Roebuck Joseph R.,
Hearshen David O.,
O'Donnell Matthew,
Raidy Tom
Publication year - 1993
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910300302
Subject(s) - spectral line , phase (matter) , eddy current , signal (programming language) , computational physics , nuclear magnetic resonance , line (geometry) , chemistry , atomic physics , physics , materials science , computer science , mathematics , geometry , programming language , organic chemistry , quantum mechanics , astronomy
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 1 H‐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 1 H‐CSI spectra from normal human brain are presented demonstrating the capabilities of the technique.