Proton T2 relaxation time of J‐coupled cerebral metabolites in rat brain at 9.4 T

Abstract

Knowledge of proton T₂ relaxation time of metabolites is essential for proper quantitation of metabolite concentrations in localized proton spectroscopy, especially at moderate to long TEs. Although the T₂ relaxation time of singlets, such as that of creatine and N‐acetylaspartate, has been characterized in several studies, similar information is lacking from coupled spin resonances of cerebral metabolites. In this study, the T₂ relaxation time of coupled spin resonances and singlet resonances of cerebral metabolites was measured in rat brain in vivo at 9.4 T. Spectra were acquired at 11 TEs using the SPin ECho, full Intensity Acquired Localized (SPECIAL) spectroscopy method. Data analysis was performed in the frequency domain with the LCModel software using simulated TE‐specific basis sets. The T₂ relaxation times in compounds showing singlet resonances were 113 ± 3 ms (total creatine), 178 ± 29 ms (total choline) and 202 ± 12 ms (N‐acetylaspartate). The T₂ values of J‐coupled metabolites ranged from 89 ± 8 ms (glutamate) to 148 ± 14 ms (myo‐inositol). Copyright © 2007 John Wiley & Sons, Ltd.