Age-related changes in long and short echo time proton magnetic resonance spectroscopy of the brain

6. No other parameters correlated with age, although Cho/Cr showed a trend towards reduction with age at both echo times, which was not significant after multiplicity correction. The age-related change in R2 of NAA is insufficient to account for the age-related decrease in NAA/Cr even at long echo, suggesting true changes in metabolite concentrations occur. The trends observed are consistent with increased creatine with age, as previously reported in single-voxel studies 7 ; the weaker correlation of Cho/Cr and mI/Cr with age compared to NAA/Cr may be attributed to the higher signal to noise of the NAA resonance in brain spectra. Lactate was not detected in any spectra. Strong lipid resonances were observed in some subjects, and the incidence increased with age (p=0.012 for logistic regression against age). Lipid occurrence was uncorrelated with cholesterol, body mass index or white matter lesions; furthermore, the lipid resonances were invariably observed in the midline of the brain. We believe the resonances to result from lipid deposits in the falx cerebri, rather than the brain tissue itself; such deposits have previously been observed in ageing populations by MRI and CT 8,9,10 , but never by MRS.