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Removing effects of eddy currents in proton MR spectroscopy
Author(s) -
Riddle William R.,
Gibbs S. Julian,
Willcott M. Robert
Publication year - 1992
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596839
Subject(s) - free induction decay , phase (matter) , nuclear magnetic resonance , eddy current , physics , spectroscopy , resonance (particle physics) , spectral line , computational physics , atomic physics , optics , magnetic resonance imaging , spin echo , medicine , quantum mechanics , astronomy , radiology
The use of pulsed gradients to define a volume of interest for localized magnetic resonance spectroscopy produces magnetic field perturbations which distort both the free induction decay and the spectrum after Fourier transformation. A technique is presented that removes the artifacts from eddy currents from a sampled free induction decay. To linearize the phase, the nonlinear phase of a reference free induction decay is subtracted from the phase of a sample free induction decay. Next, to move the frequency to resonance and perform a zero‐order phase correction, the line fit from a linear regression is subtracted from the phase. After reconstructing the free induction decay, the resulting frequency spectra are sorted into absorption mode and dispersion mode components.