Region-specific aging of the human brain as evidenced by neurochemical profiles measured noninvasively in the posterior cingulate cortex and the occipital lobe using 1 H magnetic resonance spectroscopy at 7 T

Marjańska, Małgorzata; McCarten, J. Riley; Hodges, James S.; Hemmy, Laura S; Grant, Andrea; Deelchand, Dinesh K.; Terpstra, Melissa

doi:10.1016/j.neuroscience.2017.04.035

Cited by 79 publications

(107 citation statements)

References 80 publications

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“…In the current study, the age‐associated macromolecular content difference was measured with the highest significance in the PCC (Table ). This is the same region in which our previously published metabolite spectra from a similar cohort showed reactive astrogliosis and deterioration of metabolic vigor in older adults.…”

Section: Discussionsupporting

confidence: 80%

“…In this case, the water‐scaled macromolecular concentrations obtained from LCModel analysis were multiplied by the integral of the macromolecule spectrum (0.5 to 5 ppm) for each age group. Metabolite concentrations in young and older adults have been reported previously from a subset of the spectra used in this study …”

Section: Methodsmentioning

confidence: 99%

“…Metabolite concentrations in young and older adults have been reported previously from a subset of the spectra used in this study. 38…”

Section: Spectral Processing and Quantificationmentioning

confidence: 99%

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Altered macromolecular pattern and content in the aging human brain

et al. 2017

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The resonances originating from proteins underlie those of metabolites in brain H nuclear magnetic resonance (NMR) spectra. These resonances have different physical properties from those of metabolites, such as shorter T and T relaxation time constants. The age dependence of the macromolecular pattern and content in the human brain was investigated with a focus on adults over 66 years of age using ultrahigh-field in vivo magnetic resonance spectroscopy. Eighteen young and 23 cognitively normal older adults were studied at 7 T. Metabolite spectra were acquired in the occipital cortex and the posterior cingulate cortex with single-voxel stimulated echo acquisition mode (STEAM) spectroscopy in 14 young and 20 older adults. Macromolecular spectra were acquired in the occipital cortex using an inversion recovery STEAM sequence in four young and three older adults. The macromolecular pattern was apparent over the 0.5-4.5-ppm range in the inversion recovery spectra and the 0.5-2-ppm range in the metabolite spectra. Macromolecular content was quantified from metabolite spectra using LCModel and from inversion recovery spectra using integration. Age-associated differences in the macromolecular pattern were apparent via both types of spectra, with the largest difference observed for the 1.7- and 2-ppm macromolecular resonances. A higher macromolecular content was observed in the older adults for both brain regions. Age-specific macromolecular spectra are needed when comparing metabolite spectra from subjects of differing ages because of age-associated differences in macromolecular pattern. Age-associated pattern and content differences may provide information about the aging process.

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Section: Discussionsupporting

confidence: 80%

Section: Methodsmentioning

confidence: 99%

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Altered macromolecular pattern and content in the aging human brain

et al. 2017

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“…The long TE and inversion protocols may not be efficient as the T 1 and T 2 relaxation times of mobile lipids in tumors are longer than normal brain lipids. 60 Moreover, the effect of relaxation times on the signal intensity is an important aspect to consider, as relaxation times are sensitive to changes in the microenvironment and may vary because of aging, 61 pathology, and across different brain regions. Of the three, protocol I, with short-TE and long TR, is the least sensitive protocol to relaxation effects.…”

Section: Discussionmentioning

confidence: 99%

Lactate measurement by neurochemical profiling in the dorsolateral prefrontal cortex at 7T: accuracy, precision, and relaxation times

Dehghani¹,

Q.²,

Magistretti

et al. 2019

Magnetic Resonance in Med

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Purpose This assesses the potential of measuring lactate in the human brain using three non‐editing MRS methods at 7T and compares the accuracy and precision of the methods. Methods 1H MRS data were measured in the right dorsolateral prefrontal cortex using a semi‐adiabatic spin‐echo full‐intensity acquired localized sequence with three different protocols: (I) TE = 16 ms, (II) TE = 110 ms, and (III) TE = 16 ms, TI = 300 ms. T1 and T2 relaxation times of lactate were also measured. Simulated spectra were generated for three protocols with known concentrations, using a range of spectral linewidths and SNRs to assess the effect of data quality on the measurement precision and accuracy. Results Lactate was quantified in all three protocols with mean Cramér‐Rao lower bound of 8% (I), 13% (II), and 7% (III). The T1 and T2 relaxation times of lactate were 1.9 ± 0.2 s and 94 ± 13 ms, respectively. Simulations predicted a spectral linewidth‐associated underestimation of lactate measurement. Simulations, phantom and in vivo results showed that protocol II was most affected by this underestimation. In addition, the estimation error was insensitive to a broad range of spectral linewidth with protocol I. Within‐session coefficient of variances of lactate were 6.1 ± 7.9% (I), 22.3 ± 12.3% (II), and 5.1 ± 5.4% (III), respectively. Conclusion We conclude that protocols I and III have the potential to measure lactate at 7T with good reproducibility, whereas the measurement accuracy and precision depend on spectral linewidth and SNR, respectively. Moreover, simulation is valuable for the optimization of measurement protocols in future study design and the correction for measurement bias.

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“…All spectra were visually inspected for subtraction artifacts and noise levels. All metabolite concentrations were estimated relative to creatine as occipital creatine has been shown to be stable in the aging population (21). Metabolite concentrations were only used for statistical analysis from the LC model if the Cramer-Rao bounds were less than 20%.…”

Section: Data Preprocessing/analysismentioning

confidence: 99%

Age-Related Declines in Occipital GABA are Associated with Reduced Fluid Processing Ability

Simmonite

Carp²,

Foerster

et al. 2019

Academic Radiology

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Rationale and Objectives: Healthy aging is associated with pervasive declines in cognitive, motor, and sensory functioning. There are, however, substantial individual differences in behavioral performance among older adults. Several lines of animal research link age-related reductions of gamma-aminobutyric acid (GABA), the brain’s primary inhibitory neurotransmitter, to age-related cognitive, motor, and sensory decline. Our study used proton magnetic resonance spectroscopy (MRS) at 3T to explore whether occipital GABA declines with age in humans and whether individual differences in occipital GABA are linked to individual differences in fluid processing ability. Materials and Methods: We used a MEGA-PRESS sequence that combines frequency spectral editing with a point-resolved spectroscopy sequence to quantify GABA. Spectra were obtained from a 30 × 30 × 25 mm voxel placed in the occipital cortex of 20 young adults (mean age 20.7 years) and 18 older adults (mean age 76.5 years). Participants also performed 11 fluid processing tasks outside the scanner, the results of which were z-scored and averaged to calculate a summary measure of fluid processing ability. Regression analysis was employed to determine the relationship between GABA concentrations in the occipital cortex and a summary measure of fluid processing ability. Results: Occipital GABA was significantly lower in older participants compared to the younger participants. We also observed a significant positive relationship between occipital GABA and fluid processing ability. In fact, higher GABA was associated with better task performance in 10 of the 11 tasks. Conclusion: These findings suggest that GABA levels decline with age in humans and are associated with declines in fluid processing ability.

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Region-specific aging of the human brain as evidenced by neurochemical profiles measured noninvasively in the posterior cingulate cortex and the occipital lobe using 1 H magnetic resonance spectroscopy at 7 T

Cited by 79 publications

References 80 publications

Altered macromolecular pattern and content in the aging human brain

Altered macromolecular pattern and content in the aging human brain

Lactate measurement by neurochemical profiling in the dorsolateral prefrontal cortex at 7T: accuracy, precision, and relaxation times

Age-Related Declines in Occipital GABA are Associated with Reduced Fluid Processing Ability

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