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Choi IY, Andronesi OC, Barker P, Bogner W, Edden RAE, Kaiser LG, Lee P, Marjańska M, Terpstra M, de Graaf RA. Spectral editing in 1 H magnetic resonance spectroscopy: Experts' consensus recommendations. NMR IN BIOMEDICINE 2021; 34:e4411. [PMID: 32946145 PMCID: PMC8557623 DOI: 10.1002/nbm.4411] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 05/08/2023]
Abstract
Spectral editing in in vivo 1 H-MRS provides an effective means to measure low-concentration metabolite signals that cannot be reliably measured by conventional MRS techniques due to signal overlap, for example, γ-aminobutyric acid, glutathione and D-2-hydroxyglutarate. Spectral editing strategies utilize known J-coupling relationships within the metabolite of interest to discriminate their resonances from overlying signals. This consensus recommendation paper provides a brief overview of commonly used homonuclear editing techniques and considerations for data acquisition, processing and quantification. Also, we have listed the experts' recommendations for minimum requirements to achieve adequate spectral editing and reliable quantification. These include selecting the right editing sequence, dealing with frequency drift, handling unwanted coedited resonances, spectral fitting of edited spectra, setting up multicenter clinical trials and recommending sequence parameters to be reported in publications.
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Affiliation(s)
- In-Young Choi
- Department of Neurology, Hoglund Biomedical Imaging Center, University of Kansas Medical Center, Kansas City, Kansas
| | - Ovidiu C Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Peter Barker
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, F. M. Kirby Center for Functional MRI, Kennedy Krieger Institute, Baltimore, Maryland
| | - Wolfgang Bogner
- High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, F. M. Kirby Center for Functional MRI, Kennedy Krieger Institute, Baltimore, Maryland
| | - Lana G Kaiser
- Henry H. Wheeler, Jr. Brain Imaging Center, University of California, Berkeley, California
| | - Phil Lee
- Department of Radiology, Hoglund Biomedical Imaging Center, University of Kansas Medical Center, Kansas City, Kansas
| | - Małgorzata Marjańska
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
| | - Melissa Terpstra
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
| | - Robin A de Graaf
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut
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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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Bogner W, Gagoski B, Hess AT, Bhat H, Tisdall MD, van der Kouwe AJW, Strasser B, Marjańska M, Trattnig S, Grant E, Rosen B, Andronesi OC. 3D GABA imaging with real-time motion correction, shim update and reacquisition of adiabatic spiral MRSI. Neuroimage 2014; 103:290-302. [PMID: 25255945 PMCID: PMC4312209 DOI: 10.1016/j.neuroimage.2014.09.032] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/04/2014] [Accepted: 09/15/2014] [Indexed: 12/12/2022] Open
Abstract
Gamma-aminobutyric acid (GABA) and glutamate (Glu) are the major neurotransmitters in the brain. They are crucial for the functioning of healthy brain and their alteration is a major mechanism in the pathophysiology of many neuro-psychiatric disorders. Magnetic resonance spectroscopy (MRS) is the only way to measure GABA and Glu non-invasively in vivo. GABA detection is particularly challenging and requires special MRS techniques. The most popular is MEscher-GArwood (MEGA) difference editing with single-voxel Point RESolved Spectroscopy (PRESS) localization. This technique has three major limitations: a) MEGA editing is a subtraction technique, hence is very sensitive to scanner instabilities and motion artifacts. b) PRESS is prone to localization errors at high fields (≥3T) that compromise accurate quantification. c) Single-voxel spectroscopy can (similar to a biopsy) only probe steady GABA and Glu levels in a single location at a time. To mitigate these problems, we implemented a 3D MEGA-editing MRS imaging sequence with the following three features: a) Real-time motion correction, dynamic shim updates, and selective reacquisition to eliminate subtraction artifacts due to scanner instabilities and subject motion. b) Localization by Adiabatic SElective Refocusing (LASER) to improve the localization accuracy and signal-to-noise ratio. c) K-space encoding via a weighted stack of spirals provides 3D metabolic mapping with flexible scan times. Simulations, phantom and in vivo experiments prove that our MEGA-LASER sequence enables 3D mapping of GABA+ and Glx (Glutamate+Gluatmine), by providing 1.66 times larger signal for the 3.02ppm multiplet of GABA+ compared to MEGA-PRESS, leading to clinically feasible scan times for 3D brain imaging. Hence, our sequence allows accurate and robust 3D-mapping of brain GABA+ and Glx levels to be performed at clinical 3T MR scanners for use in neuroscience and clinical applications.
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Affiliation(s)
- Wolfgang Bogner
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; MRCE, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Borjan Gagoski
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron T Hess
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK
| | | | - M Dylan Tisdall
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Andre J W van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Bernhard Strasser
- MRCE, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Małgorzata Marjańska
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - Siegfried Trattnig
- MRCE, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Ellen Grant
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bruce Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ovidiu C Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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5
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The neurochemical profile quantified by in vivo 1H NMR spectroscopy. Neuroimage 2012; 61:342-62. [DOI: 10.1016/j.neuroimage.2011.12.038] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 12/15/2011] [Indexed: 12/13/2022] Open
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Andronesi OC, Gagoski BA, Adalsteinsson E, Sorensen AG. Correlation chemical shift imaging with low-power adiabatic pulses and constant-density spiral trajectories. NMR IN BIOMEDICINE 2012; 25:195-209. [PMID: 21774010 PMCID: PMC3261335 DOI: 10.1002/nbm.1730] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 03/21/2011] [Accepted: 03/21/2011] [Indexed: 05/31/2023]
Abstract
In this work we introduce the concept of correlation chemical shift imaging (CCSI). Novel CCSI pulse sequences are demonstrated on clinical scanners for two-dimensional Correlation Spectroscopy (COSY) and Total Correlation Spectroscopy (TOCSY) imaging experiments. To date there has been limited progress reported towards a feasible and robust multivoxel 2D COSY. Localized 2D TOCSY imaging is shown for the first time in this work. Excitation with adiabatic GOIA-W(16,4) pulses (Gradient Offset Independent Adiabaticity Wurst modulation) provides minimal chemical shift displacement error, reduced lipid contamination from subcutaneous fat, uniform optimal flip angles, and efficient mixing for coupled spins, while enabling short repetition times due to low power requirements. Constant-density spiral readout trajectories are used to acquire simultaneously two spatial dimensions and f(2) frequency dimension in (k(x),k(y),t(2)) space in order to speed up data collection, while f(1) frequency dimension is encoded by consecutive time increments of t(1) in (k(x),k(y),t(1),t(2)) space. The efficient spiral sampling of the k-space enables the acquisition of a single-slice 2D COSY dataset with an 8 × 8 matrix in 8:32 min on 3 T clinical scanners, which makes it feasible for in vivo studies on human subjects. Here we present the first results obtained on phantoms, human volunteers and patients with brain tumors. The patient data obtained by us represent the first clinical demonstration of a feasible and robust multivoxel 2D COSY. Compared to the 2D J-resolved method, 2D COSY and TOCSY provide increased spectral dispersion which scales up with increasing main magnetic field strength and may have improved ability to unambiguously identify overlapping metabolites. It is expected that the new developments presented in this work will facilitate in vivo application of 2D chemical shift correlation MRS in basic science and clinical studies.
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Affiliation(s)
- Ovidiu C Andronesi
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA.
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7
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Puts NA, Edden RA. In vivo magnetic resonance spectroscopy of GABA: a methodological review. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 60:29-41. [PMID: 22293397 PMCID: PMC3383792 DOI: 10.1016/j.pnmrs.2011.06.001] [Citation(s) in RCA: 273] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 05/30/2011] [Indexed: 05/06/2023]
Affiliation(s)
- Nicolaas A.J. Puts
- Schools of Bioscience and Psychology, Cardiff University, Park Place, Cardiff, UK
| | - Richard A.E. Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- Corresponding author. Address: Russell H. Morgan Department of Radiology and Radiological Science, 600 N Wolfe St., Park 367C, Baltimore, MD 21287, USA. Tel.: +1 410 614 3418. (R.A.E. Edden)
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9
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Herath P, Gallea C, van der Veen JW, Horovitz SG, Hallett M. In vivo neurochemistry of primary focal hand dystonia: a magnetic resonance spectroscopic neurometabolite profiling study at 3T. Mov Disord 2011; 25:2800-8. [PMID: 20979122 DOI: 10.1002/mds.23306] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The neurochemical basis of dystonia is unknown. The purpose of this study was to assess the differences of the inhibitory neurotransmitter, gamma amino butyric acid (GABA), in the sensorimotor cortex and the basal ganglia using magnetic resonance spectroscopy with optimized GABA sensitivity. Twenty-two patients with focal hand dystonia and 22 healthy controls were studied. No significant differences in GABA were observed between the groups in either the sensorimotor cortex or in the basal ganglia.
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Affiliation(s)
- Priyantha Herath
- Medical Neurology Branch, Human Motor Control Section, NINDS/NIH, Bethesda, Maryland, USA.
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Andronesi OC, Ramadan S, Mountford CE, Sorensen AG. Low-power adiabatic sequences for in vivo localized two-dimensional chemical shift correlated MR spectroscopy. Magn Reson Med 2010; 64:1542-56. [PMID: 20890988 PMCID: PMC3214589 DOI: 10.1002/mrm.22535] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 04/29/2010] [Accepted: 05/21/2010] [Indexed: 12/22/2022]
Abstract
Novel low-power adiabatic sequences are demonstrated for in vivo localized two-dimensional correlated MR spectroscopy, such as correlated spectroscopy and total correlated spectroscopy. The design is based on three new elements for in vivo two-dimensional MRS: the use of gradient modulated constant adiabaticity GOIA-W(16,4) pulses for (i) localization (correlated spectroscopy and total correlated spectroscopy) and (ii) mixing (total correlated spectroscopy), and (iii) the use of longitudinal mixing (z-filter) for magnetization transfer during total correlated spectroscopy. GOIA-W(16,4) provides accurate signal localization, and more importantly, lowers the SAR for both total correlated spectroscopy mixing and localization. Longitudinal mixing improves considerably (fivefolds) the efficiency of total correlated spectroscopy transfer. These are markedly different from previous 1D editing total correlated spectroscopy sequences using spatially nonselective pulses and transverse mixing. Fully adiabatic (adiabatic mixing with adiabatic localization) and semiadiabatic (adiabatic mixing with nonadiabatic localization) methods for two-dimensional total correlated spectroscopy are compared. Results are presented for simulations, phantoms, and in vivo two-dimensional spectra from healthy volunteers and patients with brain tumors obtained on 3T clinical platforms equipped with standard hardware. To the best of our knowledge, this is the first demonstration of in vivo adiabatic two-dimensional total correlated spectroscopy and fully adiabatic two-dimensional correlated spectroscopy. It is expected that these methodological developments will advance the in vivo applicability of multi(spectrally)dimensional MRS to reliably identify metabolic biomarkers.
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Affiliation(s)
- Ovidiu C. Andronesi
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical Shool, Boston, MA 02114
- Department of Clinical Psychology, Babes-Bolyai University, Cluj-Napoca, Romania
| | - Saadallah Ramadan
- Center for Clinical Spectroscopy, Department of Radiology, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA 02115
| | - Carolyn E. Mountford
- Center for Clinical Spectroscopy, Department of Radiology, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA 02115
| | - A. Gregory Sorensen
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical Shool, Boston, MA 02114
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Detection of reduced GABA synthesis following inhibition of GABA transaminase using in vivo magnetic resonance signal of [13C]GABA C1. J Neurosci Methods 2009; 182:236-43. [PMID: 19540876 DOI: 10.1016/j.jneumeth.2009.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 06/11/2009] [Accepted: 06/11/2009] [Indexed: 11/22/2022]
Abstract
Previous in vivo magnetic resonance spectroscopy (MRS) studies of gamma-aminobutyric acid (GABA) synthesis have relied on (13)C label incorporation into GABA C2 from [1-(13)C] or [1,6-(13)C(2)]glucose. In this study, the [(13)C]GABA C1 signal at 182.3 ppm in the carboxylic/amide spectral region of localized in vivo (13)C spectra was detected. GABA-transaminase of rat brain was inhibited by administration of gabaculine after pre-labeling of GABA C1 and its metabolic precursors with exogenous [2,5-(13)C(2)]glucose. A subsequent isotope chase experiment was performed by infusing unlabeled glucose, which revealed a markedly slow change in the labeling of GABA C1 accompanying the blockade of the GABA shunt. This slow labeling of GABA at elevated GABA concentration was attributed to the relatively small intercompartmental GABA-glutamine cycling flux that constitutes the main route of (13)C label loss during the isotope chase. Because this study showed that using low RF power broadband stochastic proton decoupling is feasible at very high field strength, it has important implications for the development of carboxylic/amide (13)C MRS methods to study brain metabolism and neurotransmission in human subjects at high magnetic fields.
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Kaiser LG, Young K, Meyerhoff DJ, Mueller SG, Matson GB. A detailed analysis of localized J-difference GABA editing: theoretical and experimental study at 4 T. NMR IN BIOMEDICINE 2008; 21:22-32. [PMID: 17377933 DOI: 10.1002/nbm.1150] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The problem of low signal-to-noise ratio for gamma-aminobutyric acid (GABA) in vivo is exacerbated by inefficient detection schemes and non-optimal experimental parameters. To analyze the mechanisms for GABA signal loss of a MEGA-PRESS J-difference sequence at 4 T, numerical simulations were performed ranging from ideal to realistic experimental implementation, including volume selection and experimental radio frequency (RF) pulse shapes with a macromolecular minimization scheme. The simulations were found to be in good agreement with phantom and in vivo data from human brain. The overall GABA signal intensity for the simulations with realistic conditions for the MEGA-PRESS difference spectrum was calculated to be almost half of the signal simulated under ideal conditions (~43% signal loss). In contrast, creatine was reduced significantly less then GABA (~19% signal loss). The 'four-compartment' distribution due to J-coupling in the PRESS-based localization was one of the most significant sources of GABA signal loss, in addition to imperfect RF profiles for volume selection and editing. An alternative strategy that reduces signal loss due to the four-compartment distribution is suggested. In summary, a detailed analysis of J-difference editing is provided with estimates of the relative amounts of GABA signal losses due to various mechanisms. The numerical simulations presented in this study should facilitate both implementation of the more efficient acquisition and quantification process of J-coupled systems.
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Affiliation(s)
- L G Kaiser
- Northern California Institute for Research and Education, San Francisco, CA, USA.
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Marjanska M, Henry PG, Uğurbil K, Gruetter R. Editing through multiple bonds: Threonine detection. Magn Reson Med 2008; 59:245-51. [DOI: 10.1002/mrm.21492] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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14
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Eykyn TR, Leach MO. Selective homonuclear Hartmann–Hahn for 13C→ 13C polarization transfer in solution state NMR. Mol Phys 2007. [DOI: 10.1080/00268970701420532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Di Costanzo A, Trojsi F, Tosetti M, Schirmer T, Lechner SM, Popolizio T, Scarabino T. Proton MR spectroscopy of the brain at 3 T: an update. Eur Radiol 2007; 17:1651-62. [PMID: 17235536 DOI: 10.1007/s00330-006-0546-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2006] [Revised: 11/07/2006] [Accepted: 11/14/2006] [Indexed: 01/20/2023]
Abstract
Proton magnetic resonance spectroscopy ((1)H-MRS) provides specific metabolic information not otherwise observable by any other imaging method. (1)H-MRS of the brain at 3 T is a new tool in the modern neuroradiological armamentarium whose main advantages, with respect to the well-established and technologically advanced 1.5-T (1)H-MRS, include a higher signal-to-noise ratio, with a consequent increase in spatial and temporal resolutions, and better spectral resolution. These advantages allow the acquisition of higher quality and more easily quantifiable spectra in smaller voxels and/or in shorter times, and increase the sensitivity in metabolite detection. However, these advantages may be hampered by intrinsic field-dependent technical issues, such as decreased T(2) signal, chemical shift dispersion errors, J-modulation anomalies, increased magnetic susceptibility, eddy current artifacts, challenges in designing and obtaining appropriate radiofrequency coils, magnetic field instability and safety hazards. All these limitations have been tackled by manufacturers and researchers and have received one or more solutions. Furthermore, advanced (1)H-MRS techniques, such as specific spectral editing, fast (1)H-MRS imaging and diffusion tensor (1)H-MRS imaging, have been successfully implemented at 3 T. However, easier and more robust implementations of these techniques are still needed before they can become more widely used and undertake most of the clinical and research (1)H-MRS applications.
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Choi IY, Lee SP, Merkle H, Shen J. In vivo detection of gray and white matter differences in GABA concentration in the human brain. Neuroimage 2006; 33:85-93. [PMID: 16884929 DOI: 10.1016/j.neuroimage.2006.06.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 05/26/2006] [Accepted: 06/18/2006] [Indexed: 12/11/2022] Open
Abstract
A novel selective multiple quantum filtering-based chemical shift imaging method was developed for acquiring GABA images in the human brain at 3 T. This method allows a concomitant acquisition of an interleaved total creatine image with the same spatial resolution. Using T(1)-based image segmentation and a nonlinear least square regression analysis of GABA-to-total creatine concentration ratios in frontal and parietal lobes of healthy adult volunteers as a function of the tissue gray matter fraction, the mean GABA concentration in gray and white matter was determined to be 1.30+/-0.36 micromol/g and 0.16+/-0.16 micromol/g (mean+/-SD, n=13), respectively. It is expected that this method will become a useful tool for studying GABAergic function in the human brain in vivo.
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Affiliation(s)
- In-Young Choi
- The Nathan Kline Institute, Medical Physics, Orangeburg, NY 10962, USA.
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Choi IY, Lee SP, Shen J. In vivo single-shot three-dimensionally localized multiple quantum spectroscopy of GABA in the human brain with improved spectral selectivity. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 172:9-16. [PMID: 15589402 DOI: 10.1016/j.jmr.2004.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Revised: 09/07/2004] [Indexed: 05/24/2023]
Abstract
A single-shot multiple quantum filtering method is developed that uses two double-band frequency selective pulses for enhanced spectral selectivity in combination with a slice-selective 90 degrees, a slice-selective universal rotator 90 degrees, and a spectral-spatial pulse composed of two slice-selective universal rotator 45 degrees pulses for single-shot three-dimensional localization. The use of this selective multiple quantum filtering method for C(3) and C(4) methylene protons of GABA resulted in improved spectral selectivity for GABA and effective suppression of overlapping signals such as creatine and glutathione in each single scan, providing reliable measurements of the GABA doublet in all subjects. The concentration of GABA was measured to be 0.7 +/- 0.2 micromol/g (means +/- SD, n = 15) in the fronto-parietal region of the human brain in vivo.
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Affiliation(s)
- In-Young Choi
- The Nathan Kline Institute, Medical Physics, Orangeburg, NY 10962, USA.
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