Abstract
Although recent studies indicate that use of a single global transverse relaxation time, T~2~, per metabolite is sufficient for better than ±10% quantification precision at intermediate and short echo‐time spectroscopy in young adults, the age‐dependence of this finding is unknown. Consequently, the age effect on regional brain choline (Cho), creatine (Cr), and N‐acetylaspartate (NAA) T~2~s was examined in four age groups using 3D (four slices, 80 voxels 1 cm^3^ each) proton MR spectroscopy in an optimized two‐point protocol. Metabolite T~2~s were estimated in each voxel and in 10 gray and white matter (GM, WM) structures in 20 healthy subjects: four adolescents (13 ± 1 years old), eight young adults (26 ± 1); two middle‐aged (51 ± 6), and six elderly (74 ± 3). The results reveal that T~2~s in GM (average ± standard error of the mean) of adolescents (NAA: 301 ± 30, Cr: 162 ± 7, Cho: 263 ± 7 ms), young adults (NAA: 269 ± 7, Cr: 156 ± 7, Cho: 226 ± 9 ms), and elderly (NAA: 259 ± 13, Cr: 154 ± 8, Cho: 229 ± 14 ms), were 30%, 16%, and 10% shorter than in WM, yielding mean global T~2~s of NAA: 343, Cr: 172, and Cho: 248 ms. The elderly NAA, Cr, and Cho T~2~s were 12%, 6%, and 10% shorter than the adolescents, a change of under 1 ms/year assuming a linear decline with age. Formulae for T~2~ age‐correction for higher quantification precision are provided. Magn Reson Med 60:790–795, 2008. © 2008 Wiley‐Liss, Inc.