2020
DOI: 10.1002/mrm.28174
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T2 relaxation times of macromolecules and metabolites in the human brain at 9.4 T

Abstract: Purpose Relaxation times can contribute to spectral assignment. In this study, effective T2 relaxation times (T2eff) of macromolecules are reported for gray and white matter–rich voxels in the human brain at 9.4 T. The T2eff of macromolecules are helpful to understand their behavior and the effect they have on metabolite quantification. Additionally, for absolute quantification of metabolites with magnetic resonance spectroscopy, appropriate T2 values of metabolites must be considered. The T2 relaxation times … Show more

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Cited by 48 publications
(111 citation statements)
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“…The concentration results are thus reported in Figure 7 and Supporting Information Table . The concentration values were corrected for T 1 ‐relaxation times of MMs from this work and for T 2 ‐relaxation times from Murali‐Manohar et al, 21 with corrections as described in the Methods section. M 2.04 has the highest concentration in both GM‐ and WM‐tissue types with 78.4 ± 10.7 and 76.6 ± 10.9 protons mmol/kg respectively.…”
Section: Resultsmentioning
confidence: 99%
See 1 more Smart Citation
“…The concentration results are thus reported in Figure 7 and Supporting Information Table . The concentration values were corrected for T 1 ‐relaxation times of MMs from this work and for T 2 ‐relaxation times from Murali‐Manohar et al, 21 with corrections as described in the Methods section. M 2.04 has the highest concentration in both GM‐ and WM‐tissue types with 78.4 ± 10.7 and 76.6 ± 10.9 protons mmol/kg respectively.…”
Section: Resultsmentioning
confidence: 99%
“…normalRMM=12normaleTI2normalT1+2normaleTI1+TI2normalT1expTET2MM1expTRT1is the relaxation correction term for macromolecules. T2 MM were considered from Murali‐Manohar et al 21 and T1 MM determined from this work were taken. The denominator 1normalfCSF was implemented for partial‐volume correction arising from contributions of CSF to the voxel volume.…”
Section: Methodsmentioning
confidence: 99%
“…T 2 and T 2 of the unnamed downfield peaks from the current work have the same order of magnitude as the macromolecular peaks: 14 to 36 ms in the upfield spectrum. 27 The measured T 2 values are specific to the occipital lobe at 9.4 T and the semiLASER sequence used. Although the corrections applied for concentrations in this work are intrinsic to the semiLASER sequence, the contributions of the Carr-Purcell effect 38 to T 2 should be investigated in future work.…”
Section: T 2 Relaxationmentioning
confidence: 99%
“…NAA has a resonance at 7.82 ppm, as reported by Govindaraju et al 40 Recently, de Graaf added N-acetylaspartylglutamate (NAAG) resonances at 7.95 and 8.26 ppm in the third edition of his book. 41 Expected concentrations from upfield measurements 27 are 12 mmol/kg and 1.4 mmol/kg for NAA and NAAG, respectively. Although the measured downfield NAA concentration (7 mmol/kg) of this study is lower than expected, the total NAA concentration (17.4 mmol/kg) is in line with literature.…”
Section: Concentrations and Peak Assignmentsmentioning
confidence: 99%
“…Total NAA (tNAA) is reported as the sum contribution of NAA and NAAG, total choline (tCho) as the sum of GPC and PCh, and total creatine (tCr) as the sum of Cr and PCr. Note that macromolecule (MM) signals at 2.25 ppm and 4 ppm overlapping 2HG have a T2 relaxation (T2 ~ 20 ms 79,80 ) approximately five times shorter than T2 relaxation of 2HG at 7 T (T2 ~ 100 ms, assumed similar to glutamate 81 ), hence the MM signals will decay 20 times more than 2HG for TE = 78 ms minimizing the potential quantification bias of 2HG due to MM. Metabolic maps and quality parametric maps for SNR, CRLB and linewidth (FWHM, full width half maximum) are produced for each MRSI data set as estimated by the LCModel fitting routine.…”
Section: Methodsmentioning
confidence: 99%