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Kirov II, Tal A. Potential clinical impact of multiparametric quantitative MR spectroscopy in neurological disorders: A review and analysis. Magn Reson Med 2020; 83:22-44. [PMID: 31393032 PMCID: PMC6814297 DOI: 10.1002/mrm.27912] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/06/2019] [Accepted: 06/29/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE Unlike conventional MR spectroscopy (MRS), which only measures metabolite concentrations, multiparametric MRS also quantifies their longitudinal (T1 ) and transverse (T2 ) relaxation times, as well as the radiofrequency transmitter inhomogeneity (B1+ ). To test whether knowledge of these additional parameters can improve the clinical utility of brain MRS, we compare the conventional and multiparametric approaches in terms of expected classification accuracy in differentiating controls from patients with neurological disorders. THEORY AND METHODS A literature review was conducted to compile metabolic concentrations and relaxation times in a wide range of neuropathologies and regions of interest. Simulations were performed to construct receiver operating characteristic curves and compute the associated areas (area under the curve) to examine the sensitivity and specificity of MRS for detecting each pathology in each region. Classification accuracy was assessed using metabolite concentrations corrected using population-averages for T1 , T2 , and B1+ (conventional MRS); using metabolite concentrations corrected using per-subject values (multiparametric MRS); and using an optimal linear multiparametric estimator comprised of the metabolites' concentrations and relaxation constants (multiparametric MRS). Additional simulations were conducted to find the minimal intra-subject precision needed for each parameter. RESULTS Compared with conventional MRS, multiparametric approaches yielded area under the curve improvements for almost all neuropathologies and regions of interest. The median area under the curve increased by 0.14 over the entire dataset, and by 0.24 over the 10 instances with the largest individual increases. CONCLUSIONS Multiparametric MRS can substantially improve the clinical utility of MRS in diagnosing and assessing brain pathology, motivating the design and use of novel multiparametric sequences.
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Affiliation(s)
- Ivan I. Kirov
- Center for Advanced Imaging Innovation and Research (CAIR), Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, Department of Radiology, 660 1 Avenue, New York, NY 10016, United States of America
| | - Assaf Tal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, 234 Herzel St., Rehovot 7610001, Israel
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Landheer K, Juchem C. Simultaneous optimization of crusher and phase cycling schemes for magnetic resonance spectroscopy: an extension of dephasing optimization through coherence order pathway selection. Magn Reson Med 2019; 83:391-402. [PMID: 31529647 DOI: 10.1002/mrm.27952] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/20/2022]
Abstract
PURPOSE To extend the dephasing optimization through coherence order pathway selection (DOTCOPS) algorithm, originally designed solely for gradient crusher schemes, to include tailored phase cycling schemes for arbitrary pulse sequences and arbitrary number of coupled spins. THEORY AND METHODS The effects all possible nested and cogwheel phase cycling schemes have on the coherence order pathways for an arbitrary experiment are considered. The DOTCOPS algorithm uses a cost function to maximally eliminate unwanted coherence pathways, with schemes preferentially eliminating unwanted coherence pathways that are less affected by the crusher scheme. Efficacy was demonstrated experimentally in 2 separate MR spectroscopy (MRS) sequences: semi-localized adiabatic selective refocusing (sLASER) and MEscher-GArwood sLASER both with phantom and in vivo experiments. RESULTS For all sequences investigated, cogwheel was found to theoretically outperform typical nested phase cycling schemes. The chosen cogwheel phase cycling schemes through DOTCOPS were found to outperform a typical 2-step phase cycling scheme in both phantom and in vivo experiments. Both crusher schemes and phase cycling schemes with 8, 16, or 32 steps are presented for 6 of the most common advanced MRS sequences. CONCLUSION The DOTCOPS algorithm has been extended to provide optimal crusher and phase cycling schemes considered in tandem. DOTCOPS can be applied to any pulse sequence of interest for any number of coupled spins. DOTCOPS is now able to alleviate the long-standing issue of designing effective crusher and phase cycling schemes for complex MRS modern sequences and, as a result, is expected to improve the data quality of virtually all applications.
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Affiliation(s)
- Karl Landheer
- Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, New York
| | - Christoph Juchem
- Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, New York.,Radiology, Columbia University College of Physicians and Surgeons, New York, New York
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Shukla DK, Wijtenburg SA, Chen H, Chiappelli JJ, Kochunov P, Hong LE, Rowland LM. Anterior Cingulate Glutamate and GABA Associations on Functional Connectivity in Schizophrenia. Schizophr Bull 2019; 45:647-658. [PMID: 29912445 PMCID: PMC6483591 DOI: 10.1093/schbul/sby075] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The underlying neurobiological mechanism for abnormal functional connectivity in schizophrenia (SCZ) remains unknown. This project investigated whether glutamate and GABA, 2 metabolites that contribute to excitatory and inhibitory functions, may influence functional connectivity in SCZ. METHODS Resting-state functional magnetic resonance imaging and proton magnetic resonance spectroscopy were acquired from 58 SCZ patients and 61 healthy controls (HC). Seed-based connectivity maps were extracted between the anterior cingulate cortex (ACC) spectroscopic voxel and all other brain voxels. Magnetic resonance spectroscopy (MRS) spectra were processed to quantify glutamate and GABA levels. Regression analysis was performed to describe relationships between functional connectivity and glutamate and GABA levels. RESULTS Reduced ACC functional connectivity in SCZ was found in regions associated with several neural networks including the default mode network (DMN) compared to HC. In the HC, positive correlations were found between glutamate and both ACC-right inferior frontal gyrus functional connectivity and ACC-bilateral superior temporal gyrus functional connectivity. A negative correlation between GABA and ACC-left posterior cingulate functional connectivity was also observed in HC. These same relationships were not statistically significant in SCZ. CONCLUSIONS The present investigation is one of the first studies to examine links between functional connectivity and glutamate and GABA levels in SCZ. Results indicate that glutamate and GABA play an important role in the functional connectivity modulation in the healthy brain. The absence of glutamate and GABA correlations in areas where SCZ showed significantly reduced functional connectivity may suggest that this chemical-functional relationship is disrupted in SCZ.
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Affiliation(s)
- Dinesh K Shukla
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD,To whom correspondence should be addressed; Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, PO Box 21247, Baltimore, MD 21228, US; tel: 410-402-6028, fax: 410-402-6077, e-mail:
| | - S Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Hongji Chen
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Joshua J Chiappelli
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Peter Kochunov
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - L Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Laura M Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
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Wijtenburg SA, Near J, Korenic SA, Gaston FE, Chen H, Mikkelsen M, Chen S, Kochunov P, Hong LE, Rowland LM. Comparing the reproducibility of commonly used magnetic resonance spectroscopy techniques to quantify cerebral glutathione. J Magn Reson Imaging 2019; 49:176-183. [PMID: 29659065 PMCID: PMC6191387 DOI: 10.1002/jmri.26046] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/23/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Cerebral glutathione (GSH), a marker of oxidative stress, has been quantified in neurodegenerative diseases and psychiatric disorders using proton magnetic resonance spectroscopy (MRS). Using a reproducible MRS technique is important, as it minimizes the impact of measurement technique variability on the study results and ensures that other studies can replicate the results. HYPOTHESIS We hypothesized that very short echo time (TE) acquisitions would have comparable reproducibility to a long TE MEGA-PRESS acquisition, and that the short TE PRESS acquisition would have the poorest reproducibility. STUDY TYPE Prospective. SUBJECTS/PHANTOMS Ten healthy adults were scanned during two visits, and six metabolite phantoms containing varying concentrations of GSH and metabolites with resonances that overlap with GSH were scanned once. FIELD STRENGTH/SEQUENCE At 3T we acquired MRS data using four different sequences: PRESS, SPECIAL, PR-STEAM, and MEGA-PRESS. ASSESSMENT Reproducibility of each MRS sequence across two visits was assessed. STATISTICAL TESTS Mean coefficients of variation (CV) and mean absolute difference (AD) were used to assess reproducibility. Linear regressions were performed on data collected from phantoms to examine the agreement between known and quantified levels of GSH. RESULTS Of the four techniques, PR-STEAM had the lowest mean CV and AD (5.4% and 7.5%, respectively), implying excellent reproducibility, followed closely by PRESS (5.8% and 8.2%) and SPECIAL (8.0 and 10.1%), and finally by MEGA-PRESS (13.5% and 17.1%). Phantom data revealed excellent fits (R2 ≥ 0.98 or higher) using all methods. DATA CONCLUSION Our data suggest that GSH can be quantified reproducibly without the use of spectral editing. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:176-183.
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Affiliation(s)
- S. Andrea Wijtenburg
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jamie Near
- Centre d’Imagerie Cérébrale, Douglas Mental Health Institute, Montreal, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Canada
- Department of Psychiatry, McGill University, Montreal, Canada
| | - Stephanie A. Korenic
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Frank E. Gaston
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hongji Chen
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mark Mikkelsen
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Shuo Chen
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Peter Kochunov
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physics, University of Maryland Baltimore County, Baltimore, MD, USA
| | - L. Elliot Hong
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Laura M. Rowland
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Psychology, University of Maryland Baltimore County, Baltimore, MD, USA
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Cai X, Epstein FH. Free-breathing cine DENSE MRI using phase cycling with matchmaking and stimulated-echo image-based navigators. Magn Reson Med 2018; 80:1907-1921. [PMID: 29607538 PMCID: PMC6107388 DOI: 10.1002/mrm.27199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 02/19/2018] [Accepted: 03/06/2018] [Indexed: 01/17/2023]
Abstract
PURPOSE This study aimed to develop a self-navigated method for free-breathing spiral cine displacement encoding with stimulated echoes (DENSE), a myocardial strain imaging technique that uses phase-cycling for artifact suppression. The method needed to address 2 consequences of motion for DENSE: striping artifacts from incomplete suppression of the T1 -relaxation echo and blurring. METHODS The method identifies phase-cycled spiral interleaves at matched respiratory phases by minimizing the residual signal due to T1 relaxation after phase-cycling subtraction. Next, the method reconstructs image-based navigators from matched phase-cycled interleaves that are comprised of the stimulated echo (ste-iNAVs). Ste-iNAVs are used for motion estimation and compensation of k-space data. The method was demonstrated in phantoms and compared to diaphragm-based navigator (dNAV) and conventional iNAV (c-iNAV) methods for the reconstruction of free-breathing volunteer data sets (N = 10). RESULTS Phantom experiments demonstrated that the proposed method removes striping artifacts and blurring due to motion. Volunteer results showed that respiratory motion measured by ste-iNAVs was better correlated than c-iNAVs to dNAV data (R2 = 0.82 ± 0.03 vs. 0.70 ± 0.05, P < 0.05). Match-making reconstructions of free-breathing data sets achieved lower residual T1 -relaxation echo energy (1.04 ± 0.01 vs. 1.18 ± 0.04 for dNAV and 1.18 ± 0.03 for c-iNAV, P < 0.05), higher apparent SNR (11.93 ± 1.05 vs. 10.68 ± 1.06 for dNAV and 10.66 ± 0.99 for c-iNAV, P < 0.05), and better phase quality (0.147 ± 0.012 vs. 0.166 ± 0.017 for dNAV, P = 0.06, and 0.168 ± 0.015 for c-iNAV, P < 0.05) than dNAV and c-iNAV methods. CONCLUSION For free-breathing cine DENSE, the proposed method addresses both types of breathing-induced artifacts and provides better quality images than conventional dNAV and iNAV methods.
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Affiliation(s)
- Xiaoying Cai
- Biomedical Engineering, University of Virginia, Charlottesville, VA, United States
| | - Frederick H. Epstein
- Biomedical Engineering, University of Virginia, Charlottesville, VA, United States
- Radiology, University of Virginia, Charlottesville, VA, United States
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Gutjahr FT, Munz E, Jakob PM. Positive chemical exchange contrast in MRI using Refocused Acquisition of Chemical Exchange Transferred Excitations (RACETE). Z Med Phys 2018; 29:184-191. [PMID: 29907396 DOI: 10.1016/j.zemedi.2018.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 11/19/2022]
Abstract
PURPOSE A new chemical exchange MRI method is proposed which allows for direct detection of exchanging solute protons with concurrent water background suppression. METHODS The proposed method, RACETE (Refocused Acquisition of Chemical Exchange Transferred Excitations), is based on a stimulated-echo-technique, where the first two excitation pulses are replaced by a train of N solute-selective excitation-transfer modules. This excitation cycle is then followed by a stimulated echo acquisition via selective refocusing of exchanged solute protons now present in the solvent pool. RESULTS The obtained magnitude and phase phantom images demonstrate that with only one RACETE-imaging experiment two different chemical exchange active substances with mMol-concentrations can be detected and distinguished simultaneously. CONCLUSION The proposed RACETE-approach allows for true positive chemical exchange contrast imaging with the proven ability to exploit magnitude as well as phase image data.
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Affiliation(s)
- Fabian Tobias Gutjahr
- Universität Würzburg, Lehrstuhl für Experimentelle Physik 5, Am Hubland, 97074 Würzburg, Germany.
| | - Eberhard Munz
- Universität Würzburg, Lehrstuhl für Experimentelle Physik 5, Am Hubland, 97074 Würzburg, Germany; Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466 Gatersleben, Germany
| | - Peter Michael Jakob
- Universität Würzburg, Lehrstuhl für Experimentelle Physik 5, Am Hubland, 97074 Würzburg, Germany
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Gasparovic C, Chen H, Mullins PG. Errors in 1 H-MRS estimates of brain metabolite concentrations caused by failing to take into account tissue-specific signal relaxation. NMR IN BIOMEDICINE 2018; 31:e3914. [PMID: 29727496 DOI: 10.1002/nbm.3914] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 06/08/2023]
Abstract
Accurate measurement of brain metabolite concentrations with proton magnetic resonance spectroscopy (1 H-MRS) can be problematic because of large voxels with mixed tissue composition, requiring adjustment for differing relaxation rates in each tissue if absolute concentration estimates are desired. Adjusting for tissue-specific metabolite signal relaxation, however, also requires a knowledge of the relative concentrations of the metabolite in gray (GM) and white (WM) matter, which are not known a priori. Expressions for the estimation of the molality and molarity of brain metabolites with 1 H-MRS are extended to account for tissue-specific relaxation of the metabolite signals and examined under different assumptions with simulated and real data. Although the modified equations have two unknowns, and hence are unsolvable explicitly, they are nonetheless useful for the estimation of the effect of tissue-specific metabolite relaxation rates on concentration estimates under a range of assumptions and experimental parameters using simulated and real data. In simulated data using reported GM and WM T1 and T2 times for N-acetylaspartate (NAA) at 3 T and a hypothetical GM/WM NAA ratio, errors of 6.5-7.8% in concentrations resulted when TR = 1.5 s and TE = 0.144 s, but were reduced to less than 0.5% when TR = 6 s and TE = 0.006 s. In real data obtained at TR/TE = 1.5 s/0.04 s, the difference in the results (4%) was similar to that obtained with simulated data when assuming tissue-specific relaxation times rather than GM-WM-averaged times. Using the expressions introduced in this article, these results can be extrapolated to any metabolite or set of assumptions regarding tissue-specific relaxation. Furthermore, although serving to bound the problem, this work underscores the challenge of correcting for relaxation effects, given that relaxation times are generally not known and impractical to measure in most studies. To minimize such effects, the data should be acquired with pulse sequence parameters that minimize the effect of signal relaxation.
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Affiliation(s)
| | - Hongji Chen
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Catonsville, MD, USA
| | - Paul G Mullins
- School of Psychology, Bangor University, Bangor, Gwynedd, UK
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Volovyk O, Tal A. Application of phase rotation to STRESS localization scheme at 3 T. Magn Reson Med 2017; 79:2481-2490. [PMID: 28972290 DOI: 10.1002/mrm.26911] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/10/2017] [Accepted: 08/17/2017] [Indexed: 12/26/2022]
Abstract
PURPOSE Application of phase rotation to the STRESS (=STEAM+PRESS) localization scheme, to shorten echo time, minimize J-coupling dephasing and estimate B1+ inhomogeneity. STRESS (=STEAM + PRESS) simultaneously refocuses and acquires the double spin echo (SE123 ) and stimulated echo (STE- ) pathways, combining PRESS-like signal with lower chemical shift displacement as in STEAM. Phase rotation effectively separates coherence pathways, allows reduction of spoiling gradients moments leading to reduction in echo time. Implementing it in STRESS allows one to individually phase-correct SE123 and STE- prior to combination. Moreover, B1+ inhomogeneity can be assessed by comparing the measured ratio of resonance intensities of SE123 and STE- pathways to the simulated one. METHODS In vivo spectra were acquired from a single voxel placed in the sensory-motor cortex of 10 healthy volunteers, using phase rotation-STRESS/PRESS/STEAM sequences at 3 T scanner. The phases of each slice-selective pulse were incremented by Δϕ1/2/3=22.5°/-45°/45°. RESULTS Phase rotation-STRESS showed quantification accuracy (% Cramer Rao lower bounds) and reproducibility (% coefficients of variation) comparable to PRESS and STEAM, in both phantoms and in vivo study. Minimal echo time achieved was 13 ms. CONCLUSION Phase rotation complements STRESS by reducing echo time, allowing processing of each pathway individually prior to addition and providing B1+ estimation in single voxel proton magnetic resonance spectroscopy. Magn Reson Med 79:2481-2490, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Osnat Volovyk
- Chemical Physics Department, Weizmann Institute of Science, Rehovot, Israel
| | - Assaf Tal
- Chemical Physics Department, Weizmann Institute of Science, Rehovot, Israel
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Wijtenburg SA, West J, Korenic SA, Kuhney F, Gaston FE, Chen H, Roberts M, Kochunov P, Hong LE, Rowland LM. Glutamatergic metabolites are associated with visual plasticity in humans. Neurosci Lett 2017; 644:30-36. [PMID: 28189743 DOI: 10.1016/j.neulet.2017.02.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/01/2017] [Accepted: 02/07/2017] [Indexed: 10/20/2022]
Abstract
Long-term potentiation (LTP) is a basic cellular mechanism underlying learning and memory. LTP-like plasticity in the visual cortex can be induced by high frequency visual stimulation in rodents and humans. Since glutamate plays a fundamental role in LTP, this study investigated if visual cortical glutamate and glutamine levels, measured by proton magnetic resonance spectroscopy (MRS), relate to visual plasticity in humans. Since plasticity requires a delicate excitation and inhibition balance, GABA was also explored. Eighteen healthy participants completed MRS and a visual fMRI paradigm. Results revealed enhanced fMRI activations after high frequency visual stimulation, suggesting visual plasticity occurred. Higher activations were associated with higher resting glutamine levels after family wise error-correction. Exploratory analyses revealed that higher resting glutamate and GABA levels were associated with visual plasticity, suggesting there may be a critical excitation-inhibition balance necessary for experience dependent plasticity. This is the first empirical evidence that resting glutamine levels and potentially glutamate and GABA levels are associated with visual plasticity in humans.
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Affiliation(s)
- S Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA.
| | - Jeffrey West
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Stephanie A Korenic
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Franchesca Kuhney
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Frank E Gaston
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Hongji Chen
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Meredith Roberts
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Peter Kochunov
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA; Department of Physics, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - L Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Laura M Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA; Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA; Department of Psychology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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Wijtenburg SA, Gaston FE, Spieker EA, Korenic SA, Kochunov P, Hong LE, Rowland LM. Reproducibility of phase rotation STEAM at 3T: focus on glutathione. Magn Reson Med 2013; 72:603-9. [PMID: 24151202 DOI: 10.1002/mrm.24959] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/08/2013] [Accepted: 08/28/2013] [Indexed: 12/25/2022]
Abstract
PURPOSE The purpose of this study was to determine the reproducibility of a very short echo time (TE) phase rotation stimulated echo acquisition mode (STEAM) sequence at 3T with a focus on the detection of glutathione. METHODS Ten healthy subjects were scanned on two separate visits. Spectra were acquired from voxels placed in the anterior and posterior cingulates. Reproducibility was assessed using mean coefficients of variation (CVs) and mean absolute differences (ADs), and reliability was assessed using standard error of measurement (SEM) and intraclass correlations (ICCs). Phantoms containing glutathione and metabolites with overlapping resonances were scanned to test the validity of glutathione quantification. RESULTS Excellent reproducibility as illustrated by CVs ≤8.3% and ADs ≤11.6% for both regions was obtained for glutathione and other commonly reported metabolites. Reproducibility measures for γ-aminobutyric acid and glutamine were good overall with CVs ranging from 6.4%-10.5% and ADs ranging from 8.6%-15.5% for both regions. Glutathione absolute and relative reliability were very good (SEMs ≤9.9%) and fair (ICCs = 0.42-0.51), respectively. Phantom studies demonstrated the ability to accurately detect glutathione from other metabolites with overlapping resonances with great precision (R(2) = 0.99). CONCLUSION A very short TE phase rotation STEAM sequence proved reproducible for metabolites difficult to quantify but important for the study of psychiatric and neurological illness.
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Affiliation(s)
- S Andrea Wijtenburg
- Neuroimaging Research Program, Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Wijtenburg SA, Knight-Scott J. Very short echo time improves the precision of glutamate detection at 3T in 1H magnetic resonance spectroscopy. J Magn Reson Imaging 2011; 34:645-52. [DOI: 10.1002/jmri.22638] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 04/06/2011] [Indexed: 11/05/2022] Open
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Reconstructing very short TE phase rotation spectral data collected with multichannel phased-array coils at 3 T. Magn Reson Imaging 2011; 29:937-42. [PMID: 21550744 DOI: 10.1016/j.mri.2011.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 03/15/2011] [Accepted: 03/19/2011] [Indexed: 11/22/2022]
Abstract
Phased-array volume coils were used in conjunction with the phase rotation STEAM (PR-STEAM) spectroscopy technique to acquire very short TE data from the anterior cingulate gyrus at 3 T. A method for combining PR-STEAM data from multiple subcoils is presented. The data were acquired from seven healthy participants using PR-STEAM (repetition time/mixing time/echo time=3500/10/6.5 ms, 6 cm(3), NEX=128, spectral width=2000 Hz, 2048 complex points, Δφ(1)=135°, Δφ(2)=22.5°, Δφ(3)=112.5° and Δφ(ADC)=0°). In addition to the primary metabolites, LCModel fit results suggest that glutathione and glutamate can also be identified with Cramér-Rao lower bounds of 10% or less.
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Mekle R, Mlynárik V, Gambarota G, Hergt M, Krueger G, Gruetter R. MR spectroscopy of the human brain with enhanced signal intensity at ultrashort echo times on a clinical platform at 3T and 7T. Magn Reson Med 2009; 61:1279-85. [DOI: 10.1002/mrm.21961] [Citation(s) in RCA: 254] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abstract
The noninvasive localization of the epileptogenic zone continues to be a challenge in many patients that present as candidates for possible epilepsy surgery. Magnetic resonance imaging (MRI) techniques provide accurate anatomical definition, but despite their high resolution, these techniques fail to visualize the pathological neocortical and hippocampal changes in a sizable number of patients with focal pathologies. Further, visualized lesions on MRI may not all produce seizures. One of the keys to the understanding of the epileptogenic zone lies in the recognition of the metabolic alterations that occur in the setting of epileptic seizures. Magnetic resonance spectroscopy (MRS) is a valuable tool that can be used to study the metabolic changes seen in both acute and chronic animal models of epilepsy. Such study allows for the identification of epileptic tissue with high sensitivity and specificity. We present here a review of the use of MRS in animal models of epilepsy.
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Affiliation(s)
- Girish K Hiremath
- Department of Neurosurgery, Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, Ohio 44195, USA
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Mlynárik V, Gambarota G, Frenkel H, Gruetter R. Localized short-echo-time proton MR spectroscopy with full signal-intensity acquisition. Magn Reson Med 2006; 56:965-70. [PMID: 16991116 DOI: 10.1002/mrm.21043] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We developed a short-echo-time (TE) sequence for proton localized spectroscopy by combining a 1D add-subtract scheme with a doubly slice-selective spin-echo (SE) sequence. The sequence preserves the full magnetization available from the selected volume of interest (VOI). By reducing the number of radiofrequency (RF) pulses acting on transverse magnetization, we were able to minimize the TE to the level that is achievable with the stimulated echo acquisition mode (STEAM) technique, and also gained a twofold increase in sensitivity. The use of an adiabatic pulse in the add-subtract localization improved the efficiency of excitation in spatially inhomogeneous RF fields, which are frequently encountered at high magnetic fields. The localization performance and sensitivity gains of this method, which is termed SPin ECho, full Intensity Acquired Localized (SPECIAL) spectroscopy, were demonstrated in vivo in rat brains. In conjunction with spectroscopic imaging, a 2-microl spatial resolution was accomplished with a signal-to-noise ratio (SNR) above 30, which is usually sufficient for reliable quantification of a large number of metabolites (neurochemical profile).
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Affiliation(s)
- Vladimír Mlynárik
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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