TY - JOUR
T1 - Regional metabolite T2 in the healthy rhesus macaque brain at 7T
AU - Liu, Songtao
AU - Gonen, Oded
AU - Fleysher, Lazar
AU - Fleysher, Roman
AU - Soher, Brian J.
AU - Pilkenton, Sarah
AU - Lentz, Margaret R.
AU - Ratai, Eva Maria
AU - González, R. Gilberto
PY - 2008/5
Y1 - 2008/5
N2 - Although the rhesus macaque brain is an excellent model system for the study of neurological diseases and their responses to treatment, its small size requires much higher spatial resolution, motivating use of ultra-high-field (B0) imagers. Their weaker radio-frequency fields, however, dictate longer pulses; hence longer TE localization sequences. Due to the shorter transverse relaxation time (T2) at higher B0s, these longer TEs subject metabolites to T2-weighting, that decrease their quantification accuracy. To address this we measured the T2s of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) in several gray matter (GM) and white matter (WM) regions of four healthy rhesus macaques at 7T using three-dimensional (3D) proton MR spectroscopic imaging at (0.4 cm)3 = 64 μl spatial resolution. The results show that macaque T2s are in good agreement with those reported in humans at 7T: 169 ± 2.3 ms for NAA (mean ± SEM), 114 ± 1.9 ms for Cr, and 128 ± 2.4 ms for Cho, with no significant differences between GM and WM. The T2 histograms from 320 voxels in each animal for NAA, Cr, and Cho were similar in position and shape, indicating that they are potentially characteristic of "healthy" in this species.
AB - Although the rhesus macaque brain is an excellent model system for the study of neurological diseases and their responses to treatment, its small size requires much higher spatial resolution, motivating use of ultra-high-field (B0) imagers. Their weaker radio-frequency fields, however, dictate longer pulses; hence longer TE localization sequences. Due to the shorter transverse relaxation time (T2) at higher B0s, these longer TEs subject metabolites to T2-weighting, that decrease their quantification accuracy. To address this we measured the T2s of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) in several gray matter (GM) and white matter (WM) regions of four healthy rhesus macaques at 7T using three-dimensional (3D) proton MR spectroscopic imaging at (0.4 cm)3 = 64 μl spatial resolution. The results show that macaque T2s are in good agreement with those reported in humans at 7T: 169 ± 2.3 ms for NAA (mean ± SEM), 114 ± 1.9 ms for Cr, and 128 ± 2.4 ms for Cho, with no significant differences between GM and WM. The T2 histograms from 320 voxels in each animal for NAA, Cr, and Cho were similar in position and shape, indicating that they are potentially characteristic of "healthy" in this species.
KW - Animal models
KW - Brain metabolites, 7 tesla
KW - MR spectroscopic imaging
KW - Rhesus macaque
KW - Transverse relaxation time
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U2 - 10.1002/mrm.21574
DO - 10.1002/mrm.21574
M3 - Article
C2 - 18429024
AN - SCOPUS:42549088220
SN - 0740-3194
VL - 59
SP - 1165
EP - 1169
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
IS - 5
ER -