Total brain N-acetylaspartate concentration in normal, age-grouped females: Quantitation with non-echo proton NMR spectroscopy
✍ Scribed by Oded Gonen; A. Kasi Viswanathan; Isabelle Catalaa; James Babb; Jayaram Udupa; Robert I. Grossman
- Book ID
- 102952668
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 581 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
The intra‐individual and inter‐individual variations of the global N‐acetylaspartate (NAA) concentration were measured in a cohort of five 42 ± 5 year‐old normal females. The total NAA signal from the whole head was obtained with non‐localized non‐echo proton spectroscopy (^1^H‐MRS) and con verted into absolute mole amounts using phantom replace ment. Since NAA is assumed to be present only in neurons, its concentration was obtained by dividing these mole amounts with the brains' volume, calculated from high resolution MRI. The key feature of the procedure is its near‐complete sup pression of the intense subcutaneous and bone marrow lipids' signals, whose chemical shifts neighbor and underlay the NAA. This was achieved by exploiting the lipids' much shorter T~1~s, compared to that of NAA, for destructive interference of their signals in co‐addition following alternating, nonselective 180° inversions. The average global, inter‐individual NAA concentration in that group was found to be 10.63 m__M__ with a 95% confidence interval of 10.43–10.82 m__M__.