TY - JOUR
T1 - NMR spectral quantitation by principal-component analysis. II. Determination of frequency and phase shifts
AU - Brown, Truman R.
AU - Stoyanova, Radka
N1 - Funding Information:
We thank Dr. Ronald A. Meyer and Mr. Anthony T. Paganini for sending us their data from the rat muscle study and Dr. Fernando Arias-Mendoza for the CSI data from the Pi phantom. This work was supported in part by NIH Grants CA 54339 and CA 41078 and Siemens Medical Systems.
PY - 1996
Y1 - 1996
N2 - This paper extends the use of principal-component analysis in spectral quantification to the estimation of frequency and phase shifts in a single resonant peak across a series of spectra. The estimated parameters can be used to correct the spectra accordingly, resulting in more accurate peak-area estimation. Further, the removal of the variations in phase and frequency caused by instrumental and experimental fluctuations makes it possible to determine more accurately the remaining variations, which bear biological significance. The procedure is demonstrated on simulated data, a 3D chemical-shift-imaging dataset acquired from a cylinder of inorganic phosphate (Pi), and a set of 736 31P NMR in vivo spectra taken from a kinetic study of rat muscle energetics. In all cases, the procedure rapidly and automatically identifies the frequency and phase shifts present in the individual spectra. In the kinetic study, the procedure is used twice, first to adjust the phase and frequency of a reference peak (phosphocreatine) and then to determine the individual frequencies of the Pi peak in each of the spectra which further can be used for estimation of pH changes during the experiment.
AB - This paper extends the use of principal-component analysis in spectral quantification to the estimation of frequency and phase shifts in a single resonant peak across a series of spectra. The estimated parameters can be used to correct the spectra accordingly, resulting in more accurate peak-area estimation. Further, the removal of the variations in phase and frequency caused by instrumental and experimental fluctuations makes it possible to determine more accurately the remaining variations, which bear biological significance. The procedure is demonstrated on simulated data, a 3D chemical-shift-imaging dataset acquired from a cylinder of inorganic phosphate (Pi), and a set of 736 31P NMR in vivo spectra taken from a kinetic study of rat muscle energetics. In all cases, the procedure rapidly and automatically identifies the frequency and phase shifts present in the individual spectra. In the kinetic study, the procedure is used twice, first to adjust the phase and frequency of a reference peak (phosphocreatine) and then to determine the individual frequencies of the Pi peak in each of the spectra which further can be used for estimation of pH changes during the experiment.
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U2 - 10.1006/jmrb.1996.0106
DO - 10.1006/jmrb.1996.0106
M3 - Article
C2 - 8661304
AN - SCOPUS:0030195785
VL - 112
SP - 32
EP - 43
JO - Journal of Magnetic Resonance - Series B
JF - Journal of Magnetic Resonance - Series B
SN - 1064-1866
IS - 1
ER -