Removing effects of eddy currents in proton MR spectroscopy.
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.
Riddle
W R
WR
Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2675.
Gibbs
S J
SJ
Willcott
M R
MR
D016477:Artifacts; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*