Present address: Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, 06520–8043, USA.
Quantification issues of in vivo 1H NMR spectroscopy of the rat brain investigated at 16.4 T
Article first published online: 19 JUN 2012
Copyright © 2012 John Wiley & Sons, Ltd.
NMR in Biomedicine
Volume 26, Issue 1, pages 74–82, January 2013
How to Cite
Hong, S.-T. and Pohmann, R. (2013), Quantification issues of in vivo 1H NMR spectroscopy of the rat brain investigated at 16.4 T. NMR Biomed., 26: 74–82. doi: 10.1002/nbm.2821
- Issue published online: 26 DEC 2012
- Article first published online: 19 JUN 2012
- Manuscript Accepted: 17 APR 2012
- Manuscript Revised: 16 APR 2012
- Manuscript Received: 24 JUL 2011
- in vivo 1H NMR spectroscopy;
- Cramér–Rao lower bound
The accuracy and precision of the quantification of metabolite concentrations in in vivo 1H NMR spectroscopy are affected by linewidth and signal-to-noise ratio (SNR). To study the effect of both factors in in vivo 1H NMR spectra acquired at ultrahigh field, a reference spectrum was generated by summing nine in vivo 1H NMR spectra obtained in rat brain with a STEAM sequence at 16.4 T. By progressive deterioration of linewidth and SNR, 6400 single spectra were generated. In an accuracy study, the variation in the mean concentrations of five metabolites was mainly dependent on SNR, whereas 11 metabolites were predominantly susceptible to the linewidth. However, the standard deviations of the concentrations obtained were dependent almost exclusively on the SNR. An insignificant correlation was found between most of the heavily overlapping metabolite peaks, indicating independent and reliable quantification. Two different approaches for the consideration of macromolecular signals were evaluated. The use of prior knowledge derived by parameterization of a metabolite-nulled spectrum demonstrated improved fitting quality, with reduced Cramér–Rao lower bounds, compared to the calculation of a regularized spline baseline. Copyright © 2012 John Wiley & Sons, Ltd.