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Carlin D, Babourina-Brooks B, Arvanitis TN, Wilson M, Peet AC. Short-acquisition-time JPRESS and its application to paediatric brain tumours. MAGMA (NEW YORK, N.Y.) 2019; 32:247-258. [PMID: 30460431 PMCID: PMC6424926 DOI: 10.1007/s10334-018-0716-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/26/2018] [Accepted: 10/29/2018] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To develop and assess a short-duration JPRESS protocol for detection of overlapping metabolite biomarkers and its application to paediatric brain tumours at 3 Tesla. MATERIALS AND METHODS The short-duration protocol (6 min) was optimised and compared for spectral quality to a high-resolution (38 min) JPRESS protocol in a phantom and five healthy volunteers. The 6-min JPRESS was acquired from four paediatric brain tumours and compared with short-TE PRESS. RESULTS Metabolite identification between the 6- and 38-min protocols was comparable in phantom and volunteer data. For metabolites with Cramer-Rao lower bounds > 50%, interpretation of JPRESS increased confidence in assignment of lactate, myo-Inositol and scyllo-Inositol. JPRESS also showed promise for the detection of glycine and taurine in paediatric brain tumours when compared to short-TE MRS. CONCLUSION A 6-min JPRESS protocol is well tolerated in paediatric brain tumour patients. Visual inspection of a 6-min JPRESS spectrum enables identification of a range of metabolite biomarkers of clinical interest.
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Affiliation(s)
- Dominic Carlin
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, West Midlands, UK
- Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK
| | - Ben Babourina-Brooks
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, West Midlands, UK
- Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK
| | - Theodoros N Arvanitis
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, West Midlands, UK
- Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK
- Institute of Digital Healthcare, WMG, University of Warwick, Coventry, UK
| | - Martin Wilson
- Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Birmingham, West Midlands, UK
| | - Andrew C Peet
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, West Midlands, UK.
- Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK.
- Clinical Research Block, Institute of Child Health, Whittall Street, Birmingham, B4 6NH, UK.
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Distinguishing neuronal from astrocytic subcellular microstructures using in vivo Double Diffusion Encoded 1H MRS at 21.1 T. PLoS One 2017; 12:e0185232. [PMID: 28968410 PMCID: PMC5624579 DOI: 10.1371/journal.pone.0185232] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/09/2017] [Indexed: 12/27/2022] Open
Abstract
Measuring cellular microstructures non-invasively and achieving specificity towards a cell-type population within an interrogated in vivo tissue, remains an outstanding challenge in brain research. Magnetic Resonance Spectroscopy (MRS) provides an opportunity to achieve cellular specificity via the spectral resolution of metabolites such as N-Acetylaspartate (NAA) and myo-Inositol (mI), which are considered neuronal and astrocytic markers, respectively. Yet the information typically obtained with MRS describes metabolic concentrations, diffusion coefficients or relaxation rates rather than microstructures. Understanding how these metabolites are compartmentalized is a challenging but important goal, which so far has been mainly addressed using diffusion models. Here, we present direct in vivo evidence for the confinement of NAA and mI within sub-cellular components, namely, the randomly oriented process of neurons and astrocytes, respectively. Our approach applied Relaxation Enhanced MRS at ultrahigh (21.1 T) field, and used its high 1H sensitivity to measure restricted diffusion correlations for NAA and mI using a Double Diffusion Encoding (DDE) filter. While very low macroscopic anisotropy was revealed by spatially localized Diffusion Tensor Spectroscopy, DDE displayed characteristic amplitude modulations reporting on confinements in otherwise randomly oriented anisotropic microstructures for both metabolites. This implies that for the chosen set of parameters, the DDE measurements had a biased sensitivity towards NAA and mI sited in the more confined environments of neurites and astrocytic branches, than in the cell somata. These measurements thus provide intrinsic diffusivities and compartment diameters, and revealed subcellular neuronal and astrocytic morphologies in normal in vivo rat brains. The relevance of these measurements towards human applications—which could in turn help understand CNS plasticity as well as diagnose brain diseases—is discussed.
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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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Heo H, Kim S, Lee HH, Cho HR, Xu WJ, Lee SH, Park CK, Park S, Choi SH, Kim H. On the Utility of Short Echo Time (TE) Single Voxel 1H-MRS in Non-Invasive Detection of 2-Hydroxyglutarate (2HG); Challenges and Potential Improvement Illustrated with Animal Models Using MRUI and LCModel. PLoS One 2016; 11:e0147794. [PMID: 26820720 PMCID: PMC4731570 DOI: 10.1371/journal.pone.0147794] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 01/09/2016] [Indexed: 12/30/2022] Open
Abstract
Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) are frequently found in brain tumors, and the resulting onco–metabolite, 2–hydroxyglutarate (2HG), has been suggested to be a potential diagnostic and prognostic biomarker of the diseases. Indeed, recent studies have demonstrated the feasibility of non–invasively detecting 2HG by using proton magnetic resonance spectroscopy (1H–MRS). Due to severe spectral overlaps of 2HG with its background metabolites and spectral baselines, however, the majority of those previous studies employed spectral editing methods with long echo times (TEs) instead of the most commonly used short TE approach with spectral fitting. Consequently, the results obtained with spectral editing methods may potentially be prone to errors resulting from substantial signal loss due to relaxation. Given that the spectral region where the main signal of 2HG resides is particularly sensitive to spectral baseline in metabolite quantification, we have investigated the impact of incorporating voxel–specifically measured baselines into the spectral basis set on the performance of the conventional short TE approach in 2HG detection in rodent models (Fisher 344 rats; n = 19) of IDH1/2 mutant–overexpressing F98 glioma at 9.4T. Metabolite spectra were acquired (SPECIAL sequence) for a tumor region and the contralateral normal region of the brain for each animal. For the estimation of spectral baselines metabolite–nulled spectra were obtained (double–inversion–recovery SPECIAL sequence) for each individual voxels. Data were post–processed with and without the measured baselines using MRUI and LCModel—the two most widely used data post–processing packages. Our results demonstrate that in–vivo detection of 2HG using the conventional short TE approach is challenging even at 9.4T. However, incorporation of voxel–specifically measured spectral baselines may potentially improve its performance. Upon more thorough validation in a larger number of animals and more importantly in human patients, the potential utility of the proposed short TE acquisition with voxel–specific baseline measurement approach in 2HG detection may need to be considered in the study design.
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Affiliation(s)
- Hwon Heo
- Department of Biomedical Sciences, Seoul National University, Seoul, Korea
| | - Sungjin Kim
- Department of Biomedical Sciences, Seoul National University, Seoul, Korea
| | - Hyeong Hun Lee
- Department of Biomedical Sciences, Seoul National University, Seoul, Korea
| | - Hye Rim Cho
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Wen Jun Xu
- College of Pharmacy, Natural Product Research Institute, Seoul National University, Seoul, Korea
| | - Se-Hoon Lee
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Chul-Kee Park
- Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea
| | - Sunghyouk Park
- College of Pharmacy, Natural Product Research Institute, Seoul National University, Seoul, Korea
| | - Seung Hong Choi
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- * E-mail: (HK); (SHC)
| | - Hyeonjin Kim
- Department of Biomedical Sciences, Seoul National University, Seoul, Korea
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
- * E-mail: (HK); (SHC)
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Toncelli A, Noeske R, Cosottini M, Costagli M, Domenici V, Tiberi G, Tosetti M. STEAM-MiTiS: An MR spectroscopy method for the detection of scalar-coupled metabolites and its application to glutamate at 7 T. Magn Reson Med 2014; 74:1515-22. [DOI: 10.1002/mrm.25556] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 10/28/2014] [Accepted: 11/09/2014] [Indexed: 11/07/2022]
Affiliation(s)
| | - Ralph Noeske
- MR Applications and Workflow Development; GE Healthcare; Berlin Germany
| | - Mirco Cosottini
- Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia; University of Pisa; Pisa Italy
- Fondazione IMAGO7; Pisa Italy
| | - Mauro Costagli
- Fondazione IMAGO7; Pisa Italy
- Laboratorio di Fisica Medica e Biotecnologie per la Risonanza Magnetica IRCCS Fondazione Stella Maris; Pisa Italy
| | - Valentina Domenici
- Dipartimento di Chimica e Chimica Industriale; University of Pisa; Pisa Italy
| | - Gianluigi Tiberi
- Fondazione IMAGO7; Pisa Italy
- Laboratorio di Fisica Medica e Biotecnologie per la Risonanza Magnetica IRCCS Fondazione Stella Maris; Pisa Italy
| | - Michela Tosetti
- Fondazione IMAGO7; Pisa Italy
- Laboratorio di Fisica Medica e Biotecnologie per la Risonanza Magnetica IRCCS Fondazione Stella Maris; Pisa Italy
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Martin-Pastor M. Experiments for the editing of singlet peaks and simplification of ¹H NMR spectra of complex mixtures. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:1190-1197. [PMID: 24433106 DOI: 10.1021/jf4044869] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A 1D NMR singlet filtered experiment (s-filter) is presented for the clean editing of singlets peaks in crowded ¹H NMR spectra. The experiment affords a clean editing of singlet peaks and weak coupled signals ((n)JHH < 3 Hz), while the remaining multiplets peaks are strongly attenuated to a factor over 90% of its original intensity. The experiment provided a useful simplification of the typically congested ¹H NMR spectra of foodstuffs, and the edited signals retained most of the sensitivity and quantitativity. The versatility of the s-filter scheme permitted its easy incorporation as excitation building block into other 1D and 2D experiments, providing a further editing of the singlet responses. The combination of the 1D s-filter experiment and difference spectroscopy provided a 1D reverse singlet filtered experiment (s-filter(rev)) for the clean editing of multiplet peaks and strong suppression of singlets. The experiments proposed could be valuable to facilitate the detection and/or quantification of target compounds in complex mixtures of metabolites.
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Affiliation(s)
- Manuel Martin-Pastor
- Unidade de Resonancia Magnética, RIADT, Campus Vida, University of Santiago de Compostela , Santiago de Compostela, A Coruña 15706, Spain
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Kim H, Thompson RB, Allen PS. Enhancement of spectral editing efficacy of multiple quantum filters in in vivo proton magnetic resonance spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:90-97. [PMID: 22975239 DOI: 10.1016/j.jmr.2012.07.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/12/2012] [Accepted: 07/24/2012] [Indexed: 06/01/2023]
Abstract
The performance of multiple quantum filters (MQFs) can be disappointing when the background signal also arises from coupled spins. Moreover, at 3.0 T and even higher fields the majority of the spin systems of key brain metabolites fall into the strong-coupling regime. In this manuscript we address comprehensively, the importance of the phase of the multiple quantum coherence-generating pulse (MQ-pulse) in the design of MQFs, using both product operator and numerical analysis, in both zero and double quantum filter designs. The theoretical analyses were experimentally validated with the examples of myo-inositol editing and the separation of glutamate from glutamine. The results demonstrate that the phase of the MQ-pulse per se provides an additional spectral discrimination mechanism based on the degree of coupling beyond the conventional level-of-coherence approach of MQFs. To obtain the best spectral discrimination of strongly-coupled spin systems, therefore, the phase of the MQ-pulse must be included in the portfolio of the sequence parameters to be optimized.
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Affiliation(s)
- Hyeonjin Kim
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
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8
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Chawla S, Oleaga L, Wang S, Krejza J, Wolf RL, Woo JH, O'Rourke DM, Judy KD, Grady MS, Melhem ER, Poptani H. Role of proton magnetic resonance spectroscopy in differentiating oligodendrogliomas from astrocytomas. J Neuroimaging 2010; 20:3-8. [PMID: 19021846 DOI: 10.1111/j.1552-6569.2008.00307.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Preoperative differentiation of astrocytomas from oligodendrogliomas is clinically important, as oligodendrogliomas are more sensitive to chemotherapy. The purpose of this study was to assess the role of proton magnetic resonance spectroscopy in distinguishing astrocytomas from oligodendrogliomas. METHODS Forty-six patients [astrocytomas (n= 17) and oligodendrogliomas (n= 29)] underwent magnetic resonance imaging and multi voxel proton magnetic resonance spectroscopic imaging before treatment. Peak areas for N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myo-inositol (mI), glutamate/glutamine (Glx), and lipids + lactate (Lip+Lac) were analyzed from voxels that exhibited hyperintensity on fluid-attenuated inversion recovery images and were normalized to Cr from each voxel. The average metabolite/Cr ratios from these voxels were then compared between astrocytomas and oligodendrogliomas. Receiver-operating curve analyses were used as measures of differentiation accuracy of metabolite ratios. A threshold value for a metabolite ratio was estimated by maximizing the sum of sensitivity and specificity. RESULTS A significant difference in mI/Cr was observed between astrocytomas and oligodendrogliomas (.50 +/- .18 vs. 0.66 +/- 0.20, P < .05). Using a threshold value of .56 for mI/Cr ratio, it was possible to differentiate oligodendrogliomas from astrocytomas with a sensitivity of 72.4% and specificity of 76.4%. CONCLUSION These results suggest that mI/Cr might aid in distinguishing oligodendrogliomas from astrocytomas.
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Affiliation(s)
- Sanjeev Chawla
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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9
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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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10
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Snyder J, Thompson RB, Wilman AH. Difference spectroscopy using PRESS asymmetry: application to glutamate, glutamine, and myo-inositol. NMR IN BIOMEDICINE 2010; 23:41-47. [PMID: 19688783 DOI: 10.1002/nbm.1424] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A simple, clinically viable technique utilizing PRESS and strong coupling properties is presented for discrimination of coupled brain metabolites. The method relies on signal variation due to alteration of inter-echo timings (PRESS asymmetry) while maintaining a constant total echo time. Spin response of singlets and weakly coupled spins is unchanged due to PRESS asymmetry, allowing difference spectroscopy to detect unobstructed strongly coupled resonances. No changes to the standard PRESS sequence are required except variation of inter-echo timings. The procedure is illustrated for the separate detection of glutamate from glutamine and the detection of myo-inositol in simulation, phantom, and in vivo experiments at 4.7 T. The subtraction yields calculated from the simulation were 53% for glutamate and 75% for myo-inositol, and a resultant contribution of 96% glutamate to the total glutamate/glutamine multiplet in the 2.04-2.14 ppm range. To extend the treatment to other field strengths and metabolites, an analytical approximation based on a strongly coupled AB system was used to model individual spin groups. Subtraction spectroscopy yields for different combinations of coupling parameters were calculated for the detection of various strongly coupled metabolites at common clinical field strengths. The approximation also predicts adequate glutamate/glutamine discrimination at 3.0 T using the difference spectroscopy method.
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Affiliation(s)
- Jeff Snyder
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
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11
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Thompson RB, Allen PS. Contamination of single-voxel multiple quantum filters by external water signals arising from intermolecular multiple quantum coherences. Magn Reson Med 2009; 62:796-801. [PMID: 19449371 DOI: 10.1002/mrm.22061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Multiple-quantum filtered pulse sequences simplify overlapping metabolite spectra by the elimination of peaks from uncoupled spin species, most notably from methyl groups and water, and the minimization of unwanted coupled-spin peaks. However, it is shown in this study that a significant contaminant water signal can pass through this family of filters in the form of intermolecular multiple-quantum coherences. An imaging evaluation of a single-voxel multiple quantum filter experiment confirms that the water contamination is excited from outside of the voxel of interest, thus having an increased potential for broad spectral contamination. Phantom and in vivo experiments at 3.0 T are used to illustrate, first, significant water contamination of a single-voxel double quantum filter experiment optimized for the observation of glutamate, and second, the elimination of the unwanted water signal with conventional phase cycling and optimized filter gradient orientations.
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Affiliation(s)
- Richard B Thompson
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada.
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Abstract
Optimized myo-inositol (mI) detection is important for diagnosing and monitoring a multitude of pathological conditions of the brain. Simulations are presented in this work, performed to decide which pulse sequence has the most significant advantage in terms of improving repeatability and accuracy of mI measurements at 3T over the pulse sequence used typically in the clinic, a TE = 35 ms PRESS sequence. Five classes of pulse sequences, four previously suggested for optimized mI detection (a short TE PRESS, a Carr-Purcell PRESS sequence, an optimized STEAM sequence, an optimized zero quantum filter), and one optimized for mI detection in this work (a single quantum filter) were compared to a standard, TE = 35 ms pulse sequence. While limiting the SNR of an acquisition to the equivalent SNR of a spectrum acquired in 5 min from an 8 cc voxel, it was found through simulations that the most repeatable mI measurements would be obtained with a Carr-Purcell sequence. This sequence was implemented in a clinical scanner, and improved mI measurements were demonstrated in vivo.
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Affiliation(s)
- Ileana Hancu
- GE Global Research Center, Niskayuna, New York 12309, USA.
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Kaiser LG, Young K, Matson GB. Numerical simulations of localized high field 1H MR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 195:67-75. [PMID: 18789736 PMCID: PMC2585774 DOI: 10.1016/j.jmr.2008.08.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 08/22/2008] [Accepted: 08/22/2008] [Indexed: 05/08/2023]
Abstract
The limited bandwidths of volume selective RF pulses in localized in vivo MRS experiments introduce spatial artifacts that complicate spectral quantification of J-coupled metabolites. These effects are commonly referred to as a spatial interference or "four compartment" artifacts and are more pronounced at higher field strengths. The main focus of this study is to develop a generalized approach to numerical simulations that combines full density matrix calculations with 3D localization to investigate the spatial artifacts and to provide accurate prior knowledge for spectral fitting. Full density matrix calculations with 3D localization using experimental pulses were carried out for PRESS (TE=20, 70 ms), STEAM (TE=20, 70 ms) and LASER (TE=70 ms) pulse sequences and compared to non-localized simulations and to phantom solution data at 4 T. Additional simulations at 1.5 and 7 T were carried out for STEAM and PRESS (TE=20 ms). Four brain metabolites that represented a range from weak to strong J-coupling networks were included in the simulations (lactate, N-acetylaspartate, glutamate and myo-inositol). For longer TE, full 3D localization was necessary to achieve agreement between the simulations and phantom solution spectra for the majority of cases in all pulse sequence simulations. For short echo time (TE=20 ms), ideal pulses without localizing gradients gave results that were in agreement with phantom results at 4 T for STEAM, but not for PRESS (TE=20). Numerical simulations that incorporate volume localization using experimental RF pulses are shown to be a powerful tool for generation of accurate metabolic basis sets for spectral fitting and for optimization of experimental parameters.
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Affiliation(s)
- Lana G Kaiser
- Northern California Institute for Research and Education, San Francisco, CA 97121, USA.
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14
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Hattingen E, Lanfermann H, Quick J, Franz K, Zanella FE, Pilatus U. 1H MR spectroscopic imaging with short and long echo time to discriminate glycine in glial tumours. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2008; 22:33-41. [PMID: 18830648 DOI: 10.1007/s10334-008-0145-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 09/09/2008] [Accepted: 09/09/2008] [Indexed: 11/26/2022]
Abstract
OBJECT To investigate glycine (Gly) concentrations in low- and high-grade gliomas based on (1)H MR spectroscopic imaging (MRSI) with short and long echo time (TE). Myoinositol (MI) and Gly appear at the same resonance frequency of 3.56 ppm, but due to strong coupling the MI signal dephases more rapidly. Therefore, their contribution to the 3.56 ppm signal should be distinguishable comparing MRSI data acquired at short and long TE. MATERIALS AND METHODS (1)H MRSI (TE = 30 and 144 ms) was performed at 3 T in 29 patients with histopathological confirmed World Health Organization (WHO) grade II-IV gliomas and in FIVE healthy subjects. All spectra from the gliomas revealed increase of the 3.56 ppm resonance in the short TE spectra. Signal intensities of Gly and MI were differentiated either by analysing the short to long TE ratio of the resonance or by performing a weighted difference. Gly concentrations were compared between high-grade (WHO III-IV) and low-grade gliomas. RESULTS High-grade gliomas showed significantly higher Gly concentrations compared to low-grade gliomas. CONCLUSION Appropriate data processing of short and long TE (1)H MRSI provides a tool to distinguish and to quantify Gly and MI concentrations in gliomas. As Gly seems to be a marker of malignancy, more dedicated spectroscopic methods to differentiate these metabolites are justified.
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Affiliation(s)
- Elke Hattingen
- Institute of Neuroradiology, University of Frankfurt/Main, Frankfurt, Germany.
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15
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Yahya A, Gino Fallone B. Incorporating homonuclear polarization transfer into PRESS for proton spectral editing: illustration with lactate and glutathione. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 188:111-21. [PMID: 17638584 DOI: 10.1016/j.jmr.2007.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 06/19/2007] [Accepted: 06/19/2007] [Indexed: 05/16/2023]
Abstract
A proton spectral editing pulse sequence for the detection of metabolites with spin systems that involve weak coupling is presented. The sequence is based on homonuclear polarization transfer incorporated into the standard PRESS (Point RESolved Spectroscopy) sequence, which is a volume-selective double spin echo method, to enable spatial localization. All peaks in the region of interest are initially suppressed whether they are peaks from the target metabolite or from contaminating background. The target signal is then restored by polarization transfer from a proton that has a resonance outside the suppressed region and to which the target spins are weakly coupled. This is achieved by the application of a 90 degrees hard pulse with phase orthogonal to that of the PRESS excitation pulse at the location of the first echo in PRESS and by optimizing the two PRESS timings, TE(1) and TE(2), for most efficient yield. Background signal not coupled to any protons outside the initially saturated region remains suppressed. The advantage of this sequence compared to multiple quantum filters is that signal from singlet peaks outside the suppressed area are preserved and can thus be used as a reference. The efficacy of the sequence was verified experimentally on phantom solutions of lactate and glutathione at 3.0 T. For the AX(3) spin system of lactate, the sequence timings were optimized by product operator calculations whereas for the ABX spin system of the cysteinyl group of glutathione numerical calculations were performed for sequence timing optimization.
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Affiliation(s)
- Atiyah Yahya
- Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, Canada T6G 1Z2
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Soher BJ, Young K, Bernstein A, Aygula Z, Maudsley AA. GAVA: spectral simulation for in vivo MRS applications. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 185:291-9. [PMID: 17257868 PMCID: PMC1940040 DOI: 10.1016/j.jmr.2007.01.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 12/11/2006] [Accepted: 01/10/2007] [Indexed: 05/13/2023]
Abstract
An application that provides a flexible and easy to use interface to the GAMMA spectral simulation package is described that is targeted at investigations using in vivo MR spectroscopic methods. The program makes available a number of widely used spatially localized MRS pulse sequences and NMR parameters for commonly observed tissue metabolites, enabling spectra to be simulated for any pulse sequence parameter and viewed in an integrated display. The application is interfaced with a database for storage of all simulation parameters and results of the simulations. This application provides a convenient method for generating a priori spectral information used in parametric spectral analyses and for visual examination of the effects of difference pulse sequences and parameter settings.
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Affiliation(s)
- Brian J Soher
- Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710, USA.
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17
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Choi C, Ogilvie CJ, Malykhin N, Ngo JTV, Hartfeil MAW, Coupland NJ. Detection of the myo-inositol 4.06-ppm resonance by selective J rewinding: application to human prefrontal cortex in vivo. Magn Reson Med 2006; 54:1536-40. [PMID: 16215961 DOI: 10.1002/mrm.20688] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A new proton NMR single-voxel spectral editing strategy for the rapid measurement of myo-inositol in human brain is proposed. The spectral editing detects the 4.06-ppm, weakly coupled resonance by means of selective J rewinding. An 84.6-ms-long quadruple-resonance selective 180 degrees radiofrequency pulse, implemented within an adiabatic-refocused localization sequence, induces an in-phase triplet at 4.06 ppm, while eliminating the contribution from creatine, phosphorylethanolamine, lactate, and serine in this spectral region. The myo-inositol concentration in human prefrontal cortex is estimated to be 5.7 +/- 0.9 mumol/g (mean +/- SD, n = 7), with reference to NAA at 10 micromol/g.
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Affiliation(s)
- Changho Choi
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.
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Valette J, Guillermier M, Besret L, Boumezbeur F, Hantraye P, Lebon V. Optimized diffusion-weighted spectroscopy for measuring brain glutamate apparent diffusion coefficient on a whole-body MR system. NMR IN BIOMEDICINE 2005; 18:527-33. [PMID: 16177956 DOI: 10.1002/nbm.985] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A diffusion-weighted stimulated echo acquisition mode sequence was implemented in order to measure the glutamate apparent diffusion coefficient (ADC) in the monkey brain on a whole-body 3 T system. TE and TM were adjusted for maximizing glutamate signal intensity. Glutamate ADC was measured in a 5.8 mL voxel made of gray and white matter in macaque monkeys. The effect of post-processing on the estimated ADC was carefully assessed and appeared to be critical. Individual scan phasing and macromolecule subtraction corrected for approximately 25% and approximately 15% biases in glutamate ADC, respectively. Proper data processing yielded ADC values of 0.21 +/- 0.03 microm(2)/ms for glutamate, 0.15 +/- 0.04 microm(2)/ms for N-acetylaspartate + N-acetylaspartylglutamate, 0.12 +/- 0.03 microm(2)/ms for creatine, 0.11 +/- 0.05 microm(2)/ms for choline and 0.18 +/- 0.04 microm(2)/ms for myo-inositol.
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Coupland NJ, Ogilvie CJ, Hegadoren KM, Seres P, Hanstock CC, Allen PS. Decreased prefrontal Myo-inositol in major depressive disorder. Biol Psychiatry 2005; 57:1526-34. [PMID: 15953489 DOI: 10.1016/j.biopsych.2005.02.027] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2004] [Revised: 02/09/2005] [Accepted: 02/18/2005] [Indexed: 11/23/2022]
Abstract
BACKGROUND Postmortem studies have shown robust prefrontal cortex glial losses and more subtle neuronal changes in major depressive disorder (MDD). Earlier proton magnetic resonance spectroscopy (1H-MRS) studies of the glial marker myo-inositol in MDD were subject to potential confounds. The primary hypothesis of this study was that MDD patients would show reduced prefrontal/anterior cingulate cortex levels of myo-inositol. METHODS Thirteen nonmedicated moderate-severe MDD patients and 13 matched control subjects were studied (six male, seven female per group). Proton magnetic resonance spectroscopy stimulated echo acquisition mode spectra (3.0 T; echo time=168 msec; mixing time=28 msec; repetition time=3000 msec) were obtained from prefrontal/anterior cingulate cortex. Metabolite data were adjusted for tissue composition. RESULTS Patients with MDD showed significantly lower myo-inositol/creatine ratios (.94+/-.23) than control subjects (1.32+/-.37) [F(1,23)=6.9; p=.016]. CONCLUSIONS These data suggest a reduction of myo-inositol in prefrontal/anterior cingulate cortex in MDD, which could be a consequence of glial loss or altered glial metabolism. Additional in vivo studies of glial markers could add to the understanding of the pathophysiology of MDD.
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Affiliation(s)
- Nick J Coupland
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
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Kim H, Thompson RB, Hanstock CC, Allen PS. Variability of metabolite yield using STEAM or PRESS sequences in vivo at 3.0 T, illustrated with myo-inositol. Magn Reson Med 2005; 53:760-9. [PMID: 15799042 DOI: 10.1002/mrm.20434] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Using as an example the myo-inositol (mI) band at approximately 3.6 ppm in the proton spectrum from brain, an evaluation is presented that highlights the difficulties of quantifying metabolites with strongly coupled spins with either STEAM or PRESS and demonstrates some advantages of prospective sequence analysis when measuring their concentrations. The analysis emphasizes the variation in coupled-spin signal yield and lineshape, compared with that of uncoupled singlets such as N-acetylaspartate, a variation that differs from one metabolite spin system to another. This difference in variation between a target metabolite (e.g., mI) and its contaminating background metabolites (e.g., glutamate and taurine, etc.) is shown to provide in certain circumstances a substantial reduction in background contamination (both metabolite and macromolecule) while maintaining sufficient signal-to-noise ratio for precise quantification. For example, sequence times are demonstrated, both for STEAM and for PRESS, that, relative to the short echo-time sequences typical in the literature, enhance the signal to metabolite background of the 3.6-ppm band of mI by factors of 1.7 and 1.3, respectively, essentially eliminate the macromolecular baseline, and yet in vivo retain an S/N approximately 10 in both cases.
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Affiliation(s)
- Hyeonjin Kim
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
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Yahya A, Allen PS. Effect of strong homonuclear proton coupling on localized13C detection using PRESS. Magn Reson Med 2005; 54:1340-50. [PMID: 16270329 DOI: 10.1002/mrm.20725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The effect of strong homonuclear proton coupling on (13)C incorporation measurements by either indirect or direct means was investigated (and illustrated with glutamate) both numerically and experimentally at 3.0 T. In particular, two sequences were considered, each using a proton PRESS sequence for localization. The indirect (13)C detection method incorporated the POCE (proton observe carbon edited) technique onto PRESS, and for direct (13)C detection a DEPT (distortionless enhancement by polarization transfer) sequence was appended to the PRESS localization. Both analysis and experiment demonstrate that when strong homonuclear coupling of protons is additional to heteronuclear coupling with (13)C spins, the (13)C measures derived from either the indirect PRESS-POCE sequence or the direct-but-enhanced PRESS-DEPT sequence are significantly modified. Specifically, the MR lineshapes of both (13)C-bonded and nonbonded protons are changed during (13)C incorporation, giving rise, for example, to a potential cross-contamination of < or =30% between glutamate (13)C(3) and (13)C(4) measures from the PRESS-POCE indirect method. During direct-but-enhanced detection, the DEPT enhancement is reduced for glutamate (13)C(2), (13)C(3), and (13)C(4) but not equally, and the reduction is further exacerbated by proton PRESS localization, which gives rise to enhancements that are strong functions of PRESS TE(1) and TE(2).
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Affiliation(s)
- Atiyah Yahya
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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