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Giménez M, Cano M, Martínez-Zalacaín I, Real E, Alonso P, Segalàs C, Munuera J, Kegeles LS, Weinstein JJ, Xu X, Menchón JM, Cardoner N, Soriano-Mas C, Fullana MA. Is glutamate associated with fear extinction and cognitive behavior therapy outcome in OCD? A pilot study. Eur Arch Psychiatry Clin Neurosci 2020; 270:1003-1014. [PMID: 31432262 DOI: 10.1007/s00406-019-01056-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 08/07/2019] [Indexed: 12/15/2022]
Abstract
Cognitive behavioral therapy (CBT) including exposure and response prevention is a well-established treatment for obsessive-compulsive disorder (OCD) and is based on the principles of fear extinction. Fear extinction is linked to structural and functional variability in the ventromedial prefrontal cortex (vmPFC) and has been consistently associated with glutamate neurotransmission. The relationship between vmPFC glutamate and fear extinction and its effects on CBT outcome have not yet been explored in adults with OCD. We assessed glutamate levels in the vmPFC using 3T magnetic resonance spectroscopy, and fear extinction (learning and recall) using skin conductance responses during a 2-day experimental paradigm in OCD patients (n = 17) and in healthy controls (HC; n = 13). Obsessive-compulsive patients (n = 12) then received manualized CBT. Glutamate in the vmPFC was negatively associated with fear extinction recall and positively associated with CBT outcome (with higher glutamate levels predicting a better outcome) in OCD patients. Glutamate levels in the vmPFC in OCD patients were not significantly different from those in HC, and were not associated with OCD severity. Our results suggest that glutamate in the vmPFC is associated with fear extinction recall and CBT outcome in adult OCD patients.
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Affiliation(s)
- M Giménez
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain
| | - M Cano
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain.,Department of Clinical Sciences, School of Medicine, University of Barcelona, Casanova 143, 08036, Barcelona, Spain
| | - I Martínez-Zalacaín
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Department of Clinical Sciences, School of Medicine, University of Barcelona, Casanova 143, 08036, Barcelona, Spain
| | - E Real
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain
| | - P Alonso
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain.,Department of Clinical Sciences, School of Medicine, University of Barcelona, Casanova 143, 08036, Barcelona, Spain
| | - C Segalàs
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain
| | - J Munuera
- Diagnostic Imaging Department, Fundació de Recerca Hospital Sant Joan de Déu, Passeig Sant Joan de Déu, 2, Esplugues de Llobregat, 08950, Barcelona, Spain
| | - L S Kegeles
- Department of Psychiatry and Radiology, Columbia University, 622 W 168th St, New York, 10032, USA.,New York State Psychiatric Institute, 1051 Riverside Dr, New York, 10032, USA
| | - J J Weinstein
- Department of Psychiatry and Radiology, Columbia University, 622 W 168th St, New York, 10032, USA.,New York State Psychiatric Institute, 1051 Riverside Dr, New York, 10032, USA.,Department of Psychiatry, Stony Brook University, Stony Brook, 101 Nicolls Rd, Stony Brook, New York, 11794, USA
| | - X Xu
- Department of Psychiatry and Radiology, Columbia University, 622 W 168th St, New York, 10032, USA.,New York State Psychiatric Institute, 1051 Riverside Dr, New York, 10032, USA
| | - J M Menchón
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain.,Department of Clinical Sciences, School of Medicine, University of Barcelona, Casanova 143, 08036, Barcelona, Spain
| | - N Cardoner
- Depression and Anxiety Program, Department of Mental Health, Parc Taulí Sabadell, Hospital Universitari, Parc Taulí 1, 08208, Sabadell, Spain.,Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, Av. de Can Domènech, 737, 08193, Cerdanyola Del Vallès Barcelona, Barcelona, Spain
| | - C Soriano-Mas
- Department of Psychiatry, Bellvitge University Hospital, Bellvitge Biomedical Research Institute-IDIBELL, Feixa Llarga s/n, Hospitalet de Llobregat, 08907, Barcelona, Spain.,Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain.,Department of Psychobiology and Methodology of Health Sciences, Universitat Autònoma de Barcelona, Building B1, Ca n'Altayó, s/n, Bellaterra, 08193, Barcelona, Spain
| | - M A Fullana
- Carlos III Health Institute, Centro de Investigación Biomédica en Red de Salud Mental-CIBERSAM, Av. de Monforte de Lemos 5, 28029, Madrid, Spain. .,Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, Av. de Can Domènech, 737, 08193, Cerdanyola Del Vallès Barcelona, Barcelona, Spain. .,Psychiatry Department, Hospital Clínic-Institute of Neurosciences, CIBERSAM, C/Rosselló 140, 08036, Barcelona, Spain.
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Wong D, Schranz AL, Bartha R. Optimized in vivo brain glutamate measurement using long-echo-time semi-LASER at 7 T. NMR IN BIOMEDICINE 2018; 31:e4002. [PMID: 30144183 DOI: 10.1002/nbm.4002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 07/03/2018] [Accepted: 07/06/2018] [Indexed: 06/08/2023]
Abstract
A short echo time (TE ) is commonly used for brain glutamate measurement by 1 H MRS to minimize drawbacks of long TE such as signal modulation due to J evolution and T2 relaxation. However, J coupling causes the spectral patterns of glutamate to change with TE , and the shortest achievable TE may not produce the optimal glutamate measurement. The purpose of this study was to determine the optimal TE for glutamate measurement at 7 T using semi-LASER (localization by adiabatic selective refocusing). Time-domain simulations were performed to model the TE dependence of glutamate signal energy, a measure of glutamate signal strength, and were verified against measurements made in the human sensorimotor cortex (five subjects, 2 × 2 × 2 cm3 voxel, 16 averages) on a 7 T MRI scanner. Simulations showed a local maximum of glutamate signal energy at TE = 107 ms. In vivo, TE = 105 ms produced a low Cramér-Rao lower bound of 6.5 ± 2.0% across subjects, indicating high-quality fits of the prior knowledge model to in vivo data. TE = 105 ms also produced the greatest glutamate signal energy with the smallest inter-subject glutamate-to-creatine ratio (Glu/Cr) coefficient of variation (CV), 4.6%. Using these CVs, we performed sample size calculations to estimate the number of participants per group required to detect a 10% change in Glu/Cr between two groups with 95% confidence. 13 were required at TE = 45 ms, the shortest achievable echo time on our 7 T MRI scanner, while only 5 were required at TE = 105 ms, indicating greater statistical power. These results indicate that TE = 105 ms is optimum for in vivo glutamate measurement at 7 T with semi-LASER. Using long TE decreases power deposition by allowing lower maximum RF pulse amplitudes in conjunction with longer RF pulses. Importantly, long TE minimizes macromolecule contributions, eliminating the requirement for acquisition of separate macromolecule spectra or macromolecule fitting techniques, which add additional scan time or bias the estimated glutamate fit.
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Affiliation(s)
- Dickson Wong
- Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, London, ON, Canada
| | - Amy L Schranz
- Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, London, ON, Canada
| | - Robert Bartha
- Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, The University of Western Ontario, London, ON, Canada
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3
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Gambarota G. Optimization of metabolite detection by quantum mechanics simulations in magnetic resonance spectroscopy. Anal Biochem 2017; 529:65-78. [DOI: 10.1016/j.ab.2016.08.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 07/31/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
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Harris AD, Saleh MG, Edden RAE. Edited 1 H magnetic resonance spectroscopy in vivo: Methods and metabolites. Magn Reson Med 2017; 77:1377-1389. [PMID: 28150876 PMCID: PMC5352552 DOI: 10.1002/mrm.26619] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 12/30/2016] [Accepted: 12/30/2016] [Indexed: 12/13/2022]
Abstract
The Proton magnetic resonance (1 H-MRS) spectrum contains information about the concentration of tissue metabolites within a predefined region of interest (a voxel). The conventional spectrum in some cases obscures information about less abundant metabolites due to limited separation and complex splitting of the metabolite peaks. One method to detect these metabolites is to reduce the complexity of the spectrum using editing. This review provides an overview of the one-dimensional editing methods available to interrogate these obscured metabolite peaks. These methods include sequence optimizations, echo-time averaging, J-difference editing methods (single BASING, dual BASING, and MEGA-PRESS), constant-time PRESS, and multiple quantum filtering. It then provides an overview of the brain metabolites whose detection can benefit from one or more of these editing approaches, including ascorbic acid, γ-aminobutyric acid, lactate, aspartate, N-acetyl aspartyl glutamate, 2-hydroxyglutarate, glutathione, glutamate, glycine, and serine. Magn Reson Med 77:1377-1389, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Ashley D Harris
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada
- Child and Adolescent Imaging Research (CAIR) Program, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T3B 6A9, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Muhammad G Saleh
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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Chan KL, Puts NAJ, Snoussi K, Harris AD, Barker PB, Edden RAE. Echo time optimization for J-difference editing of glutathione at 3T. Magn Reson Med 2016; 77:498-504. [PMID: 26918659 DOI: 10.1002/mrm.26122] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 12/01/2015] [Accepted: 12/22/2015] [Indexed: 12/12/2022]
Abstract
PURPOSE To investigate the echo time (TE) dependence of J-difference editing of glutathione and to determine the optimal TE for in vivo measurements at 3T. METHODS Spatially resolved density-matrix simulations and phantom experiments were performed at a range of TEs to establish the spatial and TE modulation of glutathione signals in editing-on, editing-off, and difference spectra at 3T. In vivo data were acquired in five healthy subjects to compare a TE of 68 ms and a TE of 120 ms. At the longer TE, high-bandwidth, frequency-modulated, slice-selective refocusing pulses were also compared with conventional amplitude-modulated pulses. RESULTS Simulations and relaxation-corrected phantom experiments suggest that the maximum edited signal occurs at TE 160 ms, ignoring transverse relaxation. Considering in vivo T2 relaxation times of 67-89 ms, the optimal in vivo TE is estimated to be 120 ms. In vivo measurements showed that this TE yielded 15% more signal than TE 68 ms. A further gain of 57% resulted from using improved slice-selective refocusing pulses. CONCLUSION J-difference editing of glutathione using TE 120 ms delivers increased signal due to improved editing efficiency that more than offsets T2 losses. The additional TE also allows for use of improved slice-selective refocusing pulses, which results in additional signal gains. Magn Reson Med 77:498-504, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Kimberly L Chan
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Nicolaas A J Puts
- F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Karim Snoussi
- F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ashley D Harris
- F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter B Barker
- F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Richard A E Edden
- F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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6
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Breitkreutz DY, Fallone BG, Yahya A. Effect of J coupling on 1.3-ppm lipid methylene signal acquired with localised proton MRS at 3 T. NMR IN BIOMEDICINE 2015; 28:1324-1331. [PMID: 26314546 DOI: 10.1002/nbm.3387] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/10/2015] [Accepted: 07/30/2015] [Indexed: 06/04/2023]
Abstract
The purpose of this work was to investigate the effect of J-coupling interactions on the quantification and T2 determination of 1.3-ppm lipid methylene protons at 3 T. The response of the 1.3-ppm protons of hexanoic, heptanoic, octanoic, linoleic and oleic acid was measured as a function of point-resolved spectroscopy (PRESS) and stimulated echo acquisition mode (STEAM) TE. In addition, a narrow-bandwidth refocusing PRESS sequence designed to rewind J-coupling evolution of the 1.3-ppm protons was applied to the five fatty acids, to corn oil and to tibial bone marrow of six healthy volunteers. Peak areas were plotted as a function of TE, and data were fitted to monoexponentially decaying functions to determine Mo (the extrapolated area for TE = 0 ms) and T2 values. In phantoms, rewinding J-coupling evolution resulted in 198%, 64%, 44%, 20% and 15% higher T2 values for heptanoic, octanoic, linoleic and oleic acid, and corn oil, respectively, compared with those obtained with standard PRESS. The narrow-bandwidth PRESS sequence also resulted in significant changes in Mo , namely -77%, -22%, 28%, 23% and 28% for heptanoic, octanoic, linoleic and oleic acid, and corn oil, respectively. T2 values obtained with STEAM were closer to the values measured with narrow-bandwidth PRESS. On average, in tibial bone marrow (six volunteers) rewinding J-coupling evolution resulted in 21% ± 3% and 9 % ± 1% higher Mo and T2 values, respectively. This work demonstrates that the consequence of neglecting to consider scalar coupling effects on the quantification of 1.3-ppm lipid methylene protons and their T2 values is not negligible. The linoleic and oleic acid T2 results indicate that T2 measures of lipids with standard MRS techniques are dependent on lipid composition.
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Affiliation(s)
| | - B Gino Fallone
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
| | - Atiyah Yahya
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
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Zhang Y, Shen J. Simultaneous quantification of glutamate and glutamine by J-modulated spectroscopy at 3 Tesla. Magn Reson Med 2015; 76:725-32. [PMID: 26361892 DOI: 10.1002/mrm.25922] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 08/05/2015] [Accepted: 08/13/2015] [Indexed: 11/08/2022]
Abstract
PURPOSE The echo time (TE) averaged spectrum is the one-dimensional (1D) cross-section of the J-resolved spectrum at J = 0. In multiecho TE-averaged spectroscopy, glutamate (Glu) is differentiated from glutamine (Gln) at 3 Tesla (T). This method, however, almost entirely suppresses Gln resonance lines around 2.35 ppm, leaving Gln undetermined. This study presents a novel method for quantifying both Glu and Gln using multi-echo spectral data. METHODS A 1D cross-section of J-resolved spectroscopy at J = 7.5 Hz-referred to as J-modulated spectroscopy-was developed to simultaneously quantify Glu and Gln levels in the human brain. The transverse relaxation times (T2 s) of metabolites were first determined using conventional TE-averaged spectroscopy with different starting echo time and then incorporated into the spectral model for fitting J-modulated data. RESULTS Simulation and in vivo data showed that the resonance signals of Glu and Gln were clearly separated around 2.35 ppm in J-modulated spectroscopy. In the anterior cingulate cortex, both Glu and Gln levels were found to be significantly higher in gray matter than in white matter in healthy subjects (P < 10(-10) and < 10(-5) , respectively). CONCLUSION Gln resonances can be clearly separated from Glu and N-acetyl-aspartate around 2.35 ppm using J-modulated spectroscopy. This method can be used to quantitatively measure Glu and Gln simultaneously at 3T. Magn Reson Med 76:725-732, 2016. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Yan Zhang
- MR Spectroscopy Core Facility, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Jun Shen
- MR Spectroscopy Core Facility, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.,Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
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Prescot AP, Richards T, Dager SR, Choi C, Renshaw PF. Phase-adjusted echo time (PATE)-averaging 1 H MRS: application for improved glutamine quantification at 2.89 T. NMR IN BIOMEDICINE 2012; 25:1245-52. [PMID: 22407923 PMCID: PMC4657444 DOI: 10.1002/nbm.2795] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 01/26/2012] [Accepted: 02/01/2012] [Indexed: 05/22/2023]
Abstract
(1) H MRS investigations have reported altered glutamatergic neurotransmission in a variety of psychiatric disorders. The unraveling of glutamate from glutamine resonances is crucial for the interpretation of these observations, although this remains a challenge at clinical static magnetic field strengths. Glutamate resolution can be improved through an approach known as echo time (TE) averaging, which involves the acquisition and subsequent averaging of multiple TE steps. The process of TE averaging retains the central component of the glutamate methylene multiplet at 2.35 ppm, with the simultaneous attenuation of overlapping phase-modulated coupled resonances of glutamine and N-acetylaspartate. We have developed a novel post-processing approach, termed phase-adjusted echo time (PATE) averaging, for the retrieval of glutamine signals from a TE-averaged (1) H MRS dataset. The method works by the application of an optimal TE-specific phase term, which is derived from spectral simulation, prior to averaging over TE space. The simulation procedures and preliminary in vivo spectra acquired from the human frontal lobe at 2.89 T are presented. Three metabolite normalization schemes were developed to evaluate the frontal lobe test-retest reliability for glutamine measurement in six subjects, and the resulting values were comparable with previous reports for within-subject (9-14%) and inter-subject (14-20%) measures. Using the acquisition parameters and TE range described, glutamine quantification is possible in approximately 10 min. The post-processing methods described can also be applied retrospectively to extract glutamine and glutamate levels from previously acquired TE-averaged (1) H MRS datasets.
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Snyder J, Haas M, Dragonu I, Hennig J, Zaitsev M. Three-dimensional arbitrary voxel shapes in spectroscopy with submillisecond TEs. NMR IN BIOMEDICINE 2012; 25:1000-1006. [PMID: 22290622 DOI: 10.1002/nbm.2764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 11/24/2011] [Accepted: 11/28/2011] [Indexed: 05/31/2023]
Abstract
A novel spectroscopic method for submillisecond TEs and three-dimensional arbitrarily shaped voxels was developed and applied to phantom and in vivo measurements, with additional parallel excitation (PEX) implementation. A segmented spherical shell excitation trajectory was used in combination with appropriate radiofrequency weights for target selection in three dimensions. Measurements in a two-compartment phantom realized a TE of 955 µs, excellent spectral quality and comparable signal-to-noise ratios between accelerated (R = 2) and nonaccelerated modes. The two-compartment model allowed a comparison of the spectral suppression qualities of the method and, although outer volume signals were suppressed by factors of 1434 and 2246 compared with the theoretical unsuppressed case for the clinical and PEX modes, respectively, incomplete suppression of the outer volume (935 cm(3) compared with a target volume of 5.86 cm(3) ) resulted in a spectral contamination of 10.2% and 6.5% compared with the total signal. The method was also demonstrated in vivo in human brain on a clinical system at TE = 935 µs with good signal-to-noise ratio and spatial and spectral selection, and included LCModel relative quantification analysis. Eight metabolites showed significant fitting accuracy, including aspartate, N-acetylaspartylglutamate, glutathione and glutamate.
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Affiliation(s)
- Jeff Snyder
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany.
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Yahya A, Tessier AG, Fallone BG. Effect of J-coupling on lipid composition determination with localized proton magnetic resonance spectroscopy at 9.4 T. J Magn Reson Imaging 2011; 34:1388-96. [PMID: 21953706 DOI: 10.1002/jmri.22792] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 07/29/2011] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To demonstrate, at 9.4 T, that J-coupling interactions exhibited by lipid protons affects lipid composition determination with a point resolved spectroscopy (PRESS) sequence. MATERIALS AND METHODS Experiments were conducted on four oils (almond, corn, sesame, and sunflower), on visceral adipose tissue of a euthanized mouse, and on pure linoleic acid at 9.4 T. The 2.1, 2.3, and 2.8 ppm resonances were measured at multiple echo times (TEs) by a standard PRESS sequence and by a PRESS sequence consisting of narrow-bandwidth refocusing pulses designed to rewind the J-coupling evolution of the target peak protons in the voxel of interest. T(2) corrections were performed on both groups of data for the three peaks and lipid compositions for the oils and for the mouse tissue were determined. Lipid compositions were also calculated from a short-TE standard PRESS spectrum. RESULTS A chemical analysis of the samples was not performed; however, the oil compositions calculated from resonance peaks acquired with the PRESS sequence designed to minimize J-coupling effects, following T(2) relaxation correction, closely agreed with values in the literature, which was not the case for all of the compositions determined from the regular PRESS spectra. CONCLUSION The presented work brings to attention the significance of J-coupling effects when calculating lipid compositions from localized proton spectra.
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Affiliation(s)
- Atiyah Yahya
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
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Yahya A, Fallone BG. T(2) determination of the J-coupled methyl protons of lipids: In vivo ilustration with tibial bone marrow at 3 T. J Magn Reson Imaging 2010; 31:1514-21. [PMID: 20512909 DOI: 10.1002/jmri.22195] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To demonstrate how J-coupling modulations of the CH(3) lipid resonance can be minimized enabling a representative T(2) to be measured. MATERIALS AND METHODS Experiments were conducted on canola oil and in vivo on tibial bone marrow of four volunteers at 3 T. The T(2) of the CH(2) protons was measured with a standard point resolved spectroscopy (PRESS) sequence, whereas the T(2) of the CH(3) protons was determined with a PRESS sequence composed of narrow bandwidth refocusing pulses designed to exploit the chemical shift displacement effect and rewind the J-coupling evolution of the CH(3) protons in the desired voxel. Spectra were acquired at five echo times. RESULTS The narrow bandwidth PRESS sequence rewound the J-evolution of the CH(3) protons resulting in a T(2) curve that was well described by a monoexponential function. The mean T(2) of the bone marrow CH(3) protons was calculated to be 132.6 msec. The mean T(2) of the bone marrow CH(2) protons was estimated with a regular PRESS sequence to be 88.0 msec. The mean CH(2):CH(3) tibial bone marrow composition was estimated to be 12.0:1. CONCLUSION The presented technique permits the T(2) of the methyl protons of lipids to be determined with more accuracy by minimizing contributions from J-coupling.
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Affiliation(s)
- Atiyah Yahya
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada T6G 1Z2.
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Snyder J, Wilman A. Field strength dependence of PRESS timings for simultaneous detection of glutamate and glutamine from 1.5 to 7T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 203:66-72. [PMID: 20031459 DOI: 10.1016/j.jmr.2009.12.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 12/01/2009] [Accepted: 12/01/2009] [Indexed: 05/15/2023]
Abstract
An optimization of the PRESS sequence for magnetic resonance spectroscopy is presented to simultaneously detect the important brain metabolites of glutamate (Glu) and glutamine (Gln) at field strengths of 1.5, 3, 4.7, and 7T. Standard, clinical examinations typically use short echo times which in general are not ideal for the separation of Glu and Gln. The optimization procedure is based on numerical product operator simulations to produce yield and overlap measurements for all possible practical choices of PRESS inter-echo timings. The simulations illustrate the substantial modulations in Glu and Gln with field strength. At all field strengths, the optimized timings demonstrate a significant reduction in overlap compared to short echo PRESS, while maintaining a high metabolite signal, with Glu and Gln yields >90% when excluding T2 relaxation losses. Minimal overlap was attained at 7T (0.3% Gln contamination in the Glu signal), and 4.7T (1.2%). The optimized timings were applied in vivo on healthy volunteers at field strengths of 1.5 and 4.7T.
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Affiliation(s)
- Jeff Snyder
- Department of Physics, University of Alberta, Edmonton, Alta, Canada.
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Abstract
PURPOSE To identify the pulse sequence and acquisition parameters that result in the most accurate and repeatable measurements of glutamate (Glu) concentration in the brain at 3T. MATERIALS AND METHODS Simulations were performed to compare the accuracy and repeatability of 11 pulse sequences and acquisition parameters, within four general classes (PRESS, STEAM, Carr-Purcell PRESS [CPRESS] and TE averaged PRESS [JPRESS]), the majority of which were previously suggested as optimal for Glu detection. Three of the simulated acquisitions were implemented in a clinical scanner and measures of repeatability in vivo were compared to their simulated values. RESULTS Good agreement was demonstrated between simulated and experimentally determined measures of repeatability. Among the acquisitions considered, a CPRESS sequence with minimal echo time, together with, possibly, a short TE PRESS sequence, result in the most repeatable within session Glu measurements, while slightly overestimating the Glu concentration. Excellent accuracy is demonstrated by the simulations for a JPRESS sequence, at the expense of lower repeatability than optimal PRESS or CPRESS sequences. CONCLUSION Further proof of concept is presented toward validation of a simulation approach to understand pulse sequence performance in measuring the concentration of a given metabolite. Improved within session Glu measurement repeatability is predicted for CPRESS and demonstrated in vivo.
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Affiliation(s)
- Ileana Hancu
- GE Global Research Center, Niskayuna, New York 12309, USA.
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Yahya A, Fallone BG. Detection of glutamate and glutamine (Glx) by turbo spectroscopic imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 196:170-177. [PMID: 19071046 DOI: 10.1016/j.jmr.2008.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 10/14/2008] [Accepted: 11/10/2008] [Indexed: 05/27/2023]
Abstract
Turbo spectroscopic imaging (TSI) is a spin echo spectroscopic imaging technique in which two or more echoes are acquired per excitation to reduce the acquisition time. The application of TSI has primarily been limited to the detection of uncoupled spins because the signal from coupled spins is modulated as a function of echo time. In this work we demonstrate how the TSI sequence can be modified to observe spins like the C(2) protons of Glx (approximately 3.75 ppm) which are involved solely in weak-coupling interactions. The technique exploits the chemical shift displacement effect by employing TSI refocusing pulses that have bandwidths which are less than the chemical shift difference between the target spins and the spins to which they are weakly coupled. The modified TSI sequence rewinds the J-evolution of the target protons in the slice of interest independently of the echo time or echo spacing, thereby removing any signal variation between successive echoes (apart from T(2) relaxation effects). In this study we tailored the narrow-bandwidth TSI sequence for observation of the C(2) Glx protons. The echo time was experimentally optimized to minimize signal contamination from myo-inositol, and the efficacy of the method was verified on phantom solutions of Glx and on brain in vivo.
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Affiliation(s)
- Atiyah Yahya
- Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alta., Canada T6G 1Z2.
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