Noninvasive quantification of T2 and concentrations of ascorbate and glutathione in the human brain from the same double-edited spectra
Article first published online: 6 OCT 2010
Copyright © 2010 John Wiley & Sons, Ltd.
NMR in Biomedicine
Volume 24, Issue 3, pages 263–269, April 2011
How to Cite
Emir, U. E., Deelchand, D., Henry, P.-G. and Terpstra, M. (2011), Noninvasive quantification of T2 and concentrations of ascorbate and glutathione in the human brain from the same double-edited spectra. NMR Biomed., 24: 263–269. doi: 10.1002/nbm.1583
- Issue published online: 14 MAR 2011
- Article first published online: 6 OCT 2010
- Manuscript Accepted: 31 MAY 2010
- Manuscript Revised: 26 APR 2010
- Manuscript Received: 24 DEC 2009
The transverse relaxation times (T2) and concentrations of Ascorbate (Asc) and glutathione (GSH) were measured from a single dataset of double-edited spectra that were acquired at several TEs at 4 T in the human brain. Six TEs between 102 and 152 ms were utilized to calculate T2 for the group of 12 subjects scanned five times each. Spectra measured at all six TEs were summed to quantify the concentration in each individual scan. LCModel fitting was optimized for the quantification of the Asc and GSH double-edited spectra. When the fitted baseline was constrained to be flat, T2 was found to be 67 ms (95% confidence interval, 50–83 ms) for GSH and ≤115 ms for Asc using the sum of spectra measured over 60 scans. The Asc and GSH concentrations quantified in each of the 60 scans were 0.62 ± 0.08 and 0.81 ± 0.11 µmol/g [mean ± standard deviation (SD), n = 60], respectively, using 10 µmol/g N-acetylaspartate as an internal reference and assuming a constant influence of N-acetylaspartate and antioxidant T2 relaxation in the reference solution and in vivo. The T2 value of GSH was measured for the first time in the human brain. The data are consistent with short T2 for both antioxidants. These T2 values are essential for the absolute quantification of Asc and GSH concentrations measured at long TE, and provide a critical step towards addressing assumptions about T2, and therefore towards the quantification of concentrations without the possibility of systematic bias. Copyright © 2010 John Wiley & Sons, Ltd.