GAVA: Spectral simulation for in vivo MRS applications

Soher, Brian J.; Young, Karl; Bernstein, Aaron; Aygula, Zakaria K.; Maudsley, Andrew A.

doi:10.1016/j.jmr.2007.01.005

Cited by 109 publications

(102 citation statements)

References 54 publications

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“…Four sets of basis spectra were simulated using the GAVA software package (24). The GAVA software was modified to yield a Lorentzian lineshape instead of its default Gaussian shape.…”

Section: Discussionmentioning

confidence: 99%

Very short echo time improves the precision of glutamate detection at 3T in ¹H magnetic resonance spectroscopy

Wijtenburg

Knight‐Scott

2011

Magnetic Resonance Imaging

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Purpose: To examine the precision of glutamate detection using a very short echo time (TE) phase rotation STEAM (PR-STEAM) sequence.Materials and Methods: Spectrosopic data were acquired from the anterior cingulate gyrus in nine healthy adults using 6.5-msec TE PR-STEAM, 40-msec TE PRESS, 72-msec TE STEAM, and TE-Averaging with an effective TE of 105 msec on a clinical 3T magnetic resonance imaging (MRI) system. All data were quantified using LCModel and reported as ratios relative to total creatine.Results: Glutamate Cramer-Rao lower bounds were less than 8% for all sequences. The 6.5-msec TE PR-STEAM identified glutamate with the greatest precision (coefficient of variation [CV] of 7.1%), followed by TE-Averaging (CV of 8.9%), 40-msec TE PRESS (CV of 11.9%), and 72-msec TE STEAM (CV of 13.8%). Conclusion:In the absence of spectral editing, glutamate is best detected in the human brain at 3T using very short TEs.

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“…Four sets of basis spectra were simulated using the GAVA software package (24). The GAVA software was modified to yield a Lorentzian lineshape instead of its default Gaussian shape.…”

Section: Discussionmentioning

confidence: 99%

Very short echo time improves the precision of glutamate detection at 3T in ¹H magnetic resonance spectroscopy

Wijtenburg

Knight‐Scott

2011

Magnetic Resonance Imaging

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“…A water reference (NEX = 8) was also acquired for all datasets to be used for phase and eddy current correction. A basis set of 19 metabolites was simulated using the gamma visual analysis (GAVA) software (Soher, Young, Bernstein, Aygula, & Maudsley, 2007) for use in quantifying the 30‐ms TE MRS data: alanine, aspartate, creatine (Cr), γ‐aminobuytric acid, glucose, glutamate (Glu), glutamine (Gln), glutathione (GSH), glycine, glycerophosphocholine, lactate, myo‐inositol (mI), N‐acetylaspartate (NAA), N‐acetylaspartylglutamate, phosphocholine, phosphocreatine, phosphoroylethanolamine, scyllo‐inositol, and taurine. A basis set of eight metabolites simulated using the same software package was generated for use in quantifying 135‐ms TE data: Cr, glycerophosphocholine, lactate, mI, NAA, N‐acetylaspartylglutamate, phosphocholine, and phosphocreatine.…”

Section: Methodsmentioning

confidence: 99%

Reproducibility of quantitative structural and physiological MRI measurements

et al. 2017

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IntroductionQuantitative longitudinal magnetic resonance imaging and spectroscopy (MRI/S) is used to assess progress of brain disorders and treatment effects. Understanding the significance of MRI/S changes requires knowledge of the inherent technical and physiological consistency of these measurements. This longitudinal study examined the variance and reproducibility of commonly used quantitative MRI/S measurements in healthy subjects while controlling physiological and technical parameters.MethodsTwenty‐five subjects were imaged three times over 5 days on a Siemens 3T Verio scanner equipped with a 32‐channel phase array coil. Structural (T1, T2‐weighted, and diffusion‐weighted imaging) and physiological (pseudocontinuous arterial spin labeling, proton magnetic resonance spectroscopy) data were collected. Consistency of repeated images was evaluated with mean relative difference, mean coefficient of variation, and intraclass correlation (ICC). Finally, a “reproducibility rating” was calculated based on the number of subjects needed for a 3% and 10% difference.ResultsStructural measurements generally demonstrated excellent reproducibility (ICCs 0.872–0.998) with a few exceptions. Moderate‐to‐low reproducibility was observed for fractional anisotropy measurements in fornix and corticospinal tracts, for cortical gray matter thickness in the entorhinal, insula, and medial orbitofrontal regions, and for the count of the periependymal hyperintensive white matter regions. The reproducibility of physiological measurements ranged from excellent for most of the magnetic resonance spectroscopy measurements to moderate for permeability‐diffusivity coefficients in cingulate gray matter to low for regional blood flow in gray and white matter.DiscussionThis study demonstrates a high degree of longitudinal consistency across structural and physiological measurements in healthy subjects, defining the inherent variability in these commonly used sequences. Additionally, this study identifies those areas where caution should be exercised in interpretation. Understanding this variability can serve as the basis for interpretation of MRI/S data in the assessment of neurological disorders and treatment effects.

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“…A water reference (NEX = 8) was collected and utilized for phasing and eddy current correction. A basis set was simulated using the GAVA software package (Soher et al, 2007) that was modified to yield a Lorentzian lineshape instead of its default Gaussian lineshape as previously reported . This basis set was imported into LCModel, an automated curve fitting software package (Provencher, 1993) for metabolite quantification.…”

Section: White Matter Mrsmentioning

confidence: 99%

Tryptophan Metabolism and White Matter Integrity in Schizophrenia

Chiappelli

Postolache

Kochunov

et al. 2016

Neuropsychopharmacol

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Schizophrenia is associated with abnormalities in the structure and functioning of white matter, but the underlying neuropathology is unclear. We hypothesized that increased tryptophan degradation in the kynurenine pathway could be associated with white matter microstructure and biochemistry, potentially contributing to white matter abnormalities in schizophrenia. To test this, fasting plasma samples were obtained from 37 schizophrenia patients and 38 healthy controls and levels of total tryptophan and its metabolite kynurenine were assessed. The ratio of kynurenine to tryptophan was used as an index of tryptophan catabolic activity in this pathway. White matter structure and function were assessed by diffusion tensor imaging (DTI) and 1 H magnetic resonance spectroscopy (MRS). Tryptophan levels were significantly lower (po0.001), and kynurenine/tryptophan ratios were correspondingly higher (p = 0.018) in patients compared with controls. In patients, lower plasma tryptophan levels corresponded to lower structural integrity (DTI fractional anisotropy) (r = 0.347, p = 0.038). In both patients and controls, the kynurenine/tryptophan ratio was inversely correlated with frontal white matter glutamate level (r = − 0.391 and − 0.350 respectively, p = 0.024 and 0.036). These results provide initial evidence implicating abnormal tryptophan/ kynurenine pathway activity in changes to white matter integrity and white matter glutamate in schizophrenia.

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GAVA: Spectral simulation for in vivo MRS applications

Cited by 109 publications

References 54 publications

Very short echo time improves the precision of glutamate detection at 3T in ¹H magnetic resonance spectroscopy

Very short echo time improves the precision of glutamate detection at 3T in ¹H magnetic resonance spectroscopy

Reproducibility of quantitative structural and physiological MRI measurements

Tryptophan Metabolism and White Matter Integrity in Schizophrenia

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GAVA: Spectral simulation for in vivo MRS applications

Cited by 109 publications

References 54 publications

Very short echo time improves the precision of glutamate detection at 3T in 1H magnetic resonance spectroscopy

Very short echo time improves the precision of glutamate detection at 3T in 1H magnetic resonance spectroscopy

Reproducibility of quantitative structural and physiological MRI measurements

Tryptophan Metabolism and White Matter Integrity in Schizophrenia

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Very short echo time improves the precision of glutamate detection at 3T in ¹H magnetic resonance spectroscopy

Very short echo time improves the precision of glutamate detection at 3T in ¹H magnetic resonance spectroscopy