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Chen D, Lin M, Liu H, Li J, Zhou Y, Kang T, Lin L, Wu Z, Wang J, Li J, Lin J, Chen X, Guo D, Qu X. Magnetic Resonance Spectroscopy Quantification Aided by Deep Estimations of Imperfection Factors and Macromolecular Signal. IEEE Trans Biomed Eng 2024; 71:1841-1852. [PMID: 38224519 DOI: 10.1109/tbme.2024.3354123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
OBJECTIVE Magnetic Resonance Spectroscopy (MRS) is an important technique for biomedical detection. However, it is challenging to accurately quantify metabolites with proton MRS due to serious overlaps of metabolite signals, imperfections because of non-ideal acquisition conditions, and interference with strong background signals mainly from macromolecules. The most popular method, LCModel, adopts complicated non-linear least square to quantify metabolites and addresses these problems by designing empirical priors such as basis-sets, imperfection factors. However, when the signal-to-noise ratio of MRS signal is low, the solution may have large deviation. METHODS Linear Least Squares (LLS) is integrated with deep learning to reduce the complexity of solving this overall quantification. First, a neural network is designed to explicitly predict the imperfection factors and the overall signal from macromolecules. Then, metabolite quantification is solved analytically with the introduced LLS. In our Quantification Network (QNet), LLS takes part in the backpropagation of network training, which allows the feedback of the quantification error into metabolite spectrum estimation. This scheme greatly improves the generalization to metabolite concentrations unseen in training compared to the end-to-end deep learning method. RESULTS Experiments show that compared with LCModel, the proposed QNet, has smaller quantification errors for simulated data, and presents more stable quantification for 20 healthy in vivo data at a wide range of signal-to-noise ratio. QNet also outperforms other end-to-end deep learning methods. CONCLUSION This study provides an intelligent, reliable and robust MRS quantification. SIGNIFICANCE QNet is the first LLS quantification aided by deep learning.
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Chen X, Li J, Chen D, Zhou Y, Tu Z, Lin M, Kang T, Lin J, Gong T, Zhu L, Zhou J, Lin OY, Guo J, Dong J, Guo D, Qu X. CloudBrain-MRS: An intelligent cloud computing platform for in vivo magnetic resonance spectroscopy preprocessing, quantification, and analysis. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 358:107601. [PMID: 38039654 DOI: 10.1016/j.jmr.2023.107601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/03/2023]
Abstract
Magnetic resonance spectroscopy (MRS) is an important clinical imaging method for diagnosis of diseases. MRS spectrum is used to observe the signal intensity of metabolites or further infer their concentrations. Although the magnetic resonance vendors commonly provide basic functions of spectrum plots and metabolite quantification, the spread of clinical research of MRS is still limited due to the lack of easy-to-use processing software or platform. To address this issue, we have developed CloudBrain-MRS, a cloud-based online platform that provides powerful hardware and advanced algorithms. The platform can be accessed simply through a web browser, without the need of any program installation on the user side. CloudBrain-MRS also integrates the classic LCModel and advanced artificial intelligence algorithms and supports batch preprocessing, quantification, and analysis of MRS data from different vendors. Additionally, the platform offers useful functions: (1) Automatically statistical analysis to find biomarkers for diseases; (2) Consistency verification between the classic and artificial intelligence quantification algorithms; (3) Colorful three-dimensional visualization for easy observation of individual metabolite spectrum. Last, data of both healthy subjects and patients with mild cognitive impairment are used to demonstrate the functions of the platform. To the best of our knowledge, this is the first cloud computing platform for in vivo MRS with artificial intelligence processing. We have shared our cloud platform at MRSHub, providing at least two years of free access and service. If you are interested, please visit https://mrshub.org/software_all/#CloudBrain-MRS or https://csrc.xmu.edu.cn/CloudBrain.html.
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Affiliation(s)
- Xiaodie Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Jiayu Li
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Dicheng Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Yirong Zhou
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Zhangren Tu
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Meijin Lin
- Department of Applied Marine Physics & Engineering, Xiamen University, Xiamen, China
| | - Taishan Kang
- Department of Radiology, Zhongshan Hospital Affiliated to Xiamen University, Xiamen, China
| | - Jianzhong Lin
- Department of Radiology, Zhongshan Hospital Affiliated to Xiamen University, Xiamen, China
| | - Tao Gong
- Departments of Radiology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Liuhong Zhu
- Department of Radiology, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, China
| | - Jianjun Zhou
- Department of Radiology, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, China
| | - Ou-Yang Lin
- Department of Medical Imaging of Southeast Hospital, Medical College of Xiamen University, Xiamen, China
| | - Jiefeng Guo
- Department of Microelectronics and Integrated Circuit, Xiamen University, Xiamen, China
| | - Jiyang Dong
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Di Guo
- School of Computer and Information Engineering, Xiamen University of Technology, Xiamen, China
| | - Xiaobo Qu
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.
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Zhang Y, Shen J. Quantification of spatially localized MRS by a novel deep learning approach without spectral fitting. Magn Reson Med 2023; 90:1282-1296. [PMID: 37183798 PMCID: PMC10524908 DOI: 10.1002/mrm.29711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 04/05/2023] [Accepted: 04/29/2023] [Indexed: 05/16/2023]
Abstract
PURPOSE To propose a novel end-to-end deep learning model to quantify absolute metabolite concentrations from in vivo J-point resolved spectroscopy (JPRESS) without using spectral fitting. METHODS A novel encoder-decoder-style neural network was created, which was trained to predict metabolite concentrations and individual component signals concurrently from 3T JPRESS data in the time domain. The training data set contained 100 000 samples created by spin-density simulations using experimentally used RF pulses. Concentrations, phase, frequencies, linewidths, and T2 relaxation times in the training data set were varied over a large range with uniform distributions. Random synthesized noise and extraneous signals were added to the data set. Two thousand validation samples were created similarly to the training data set but with mean concentrations close to in vivo values. An in vivo test was conducted with 20 samples acquired from the human brain. RESULTS Both validation and in vivo test results showed that the proposed model successfully predicted metabolite concentrations as well as individual metabolite signals without involving spectral fitting, while extraneous peaks or unregistered signals were filtered out. Compared with the short-TE spectral fitting by LCModel, the proposed method had the advantage that the undesired correlations between the estimated concentrations and noise levels and between metabolites were eliminated or substantially reduced. CONCLUSION The proposed method provides a working deep learning model that directly maps in vivo JPRESS data to metabolite concentrations. Because spectral fitting is not used, the trained model does not depend on the assumptions associated with parameter tuning when applied to in vivo data.
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Affiliation(s)
- Yan Zhang
- National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Jun Shen
- National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
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van de Sande DMJ, Merkofer JP, Amirrajab S, Veta M, van Sloun RJG, Versluis MJ, Jansen JFA, van den Brink JS, Breeuwer M. A review of machine learning applications for the proton MR spectroscopy workflow. Magn Reson Med 2023. [PMID: 37402235 DOI: 10.1002/mrm.29793] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 07/06/2023]
Abstract
This literature review presents a comprehensive overview of machine learning (ML) applications in proton MR spectroscopy (MRS). As the use of ML techniques in MRS continues to grow, this review aims to provide the MRS community with a structured overview of the state-of-the-art methods. Specifically, we examine and summarize studies published between 2017 and 2023 from major journals in the MR field. We categorize these studies based on a typical MRS workflow, including data acquisition, processing, analysis, and artificial data generation. Our review reveals that ML in MRS is still in its early stages, with a primary focus on processing and analysis techniques, and less attention given to data acquisition. We also found that many studies use similar model architectures, with little comparison to alternative architectures. Additionally, the generation of artificial data is a crucial topic, with no consistent method for its generation. Furthermore, many studies demonstrate that artificial data suffers from generalization issues when tested on in vivo data. We also conclude that risks related to ML models should be addressed, particularly for clinical applications. Therefore, output uncertainty measures and model biases are critical to investigate. Nonetheless, the rapid development of ML in MRS and the promising results from the reviewed studies justify further research in this field.
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Affiliation(s)
- Dennis M J van de Sande
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Julian P Merkofer
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Sina Amirrajab
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Mitko Veta
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Ruud J G van Sloun
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Philips Research, Philips Research, Eindhoven, The Netherlands
| | | | - Jacobus F A Jansen
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | | | - Marcel Breeuwer
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- MR R&D - Clinical Science, Philips Healthcare, Best, The Netherlands
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Shamaei AM, Starcukova J, Starcuk Z. Physics-informed deep learning approach to quantification of human brain metabolites from magnetic resonance spectroscopy data. Comput Biol Med 2023; 158:106837. [PMID: 37044049 DOI: 10.1016/j.compbiomed.2023.106837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/06/2023] [Accepted: 03/26/2023] [Indexed: 04/08/2023]
Abstract
PURPOSE While the recommended analysis method for magnetic resonance spectroscopy data is linear combination model (LCM) fitting, the supervised deep learning (DL) approach for quantification of MR spectroscopy (MRS) and MR spectroscopic imaging (MRSI) data recently showed encouraging results; however, supervised learning requires ground truth fitted spectra, which is not practical. Moreover, this work investigates the feasibility and efficiency of the LCM-based self-supervised DL method for the analysis of MRS data. METHOD We present a novel DL-based method for the quantification of relative metabolite concentrations, using quantum-mechanics simulated metabolite responses and neural networks. We trained, validated, and evaluated the proposed networks with simulated and publicly accessible in-vivo human brain MRS data and compared the performance with traditional methods. A novel adaptive macromolecule fitting algorithm is included. We investigated the performance of the proposed methods in a Monte Carlo (MC) study. RESULT The validation using low-SNR simulated data demonstrated that the proposed methods could perform quantification comparably to other methods. The applicability of the proposed method for the quantification of in-vivo MRS data was demonstrated. Our proposed networks have the potential to reduce computation time significantly. CONCLUSION The proposed model-constrained deep neural networks trained in a self-supervised manner can offer fast and efficient quantification of MRS and MRSI data. Our proposed method has the potential to facilitate clinical practice by enabling faster processing of large datasets such as high-resolution MRSI datasets, which may have thousands of spectra.
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Vega G, Ricaurte G, Estrada-Castrillón M, Reyngoudt H, Cardona OM, Gallo-Villegas JA, Narvaez-Sanchez R, Calderón JC. In vivo absolute quantification of carnosine in the vastus lateralis muscle with 1H MRS using a surface coil and water as internal reference. Skeletal Radiol 2023; 52:157-165. [PMID: 35978163 DOI: 10.1007/s00256-022-04149-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 08/03/2022] [Accepted: 08/04/2022] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To standardize a method for 1H MRS intramuscular absolute quantification of carnosine in the thigh, using a surface coil and water as internal reference. MATERIALS AND METHODS Carnosine spectra were acquired in phantoms (5, 10, and 15 mM) as well as in the right gastrocnemius medialis (GM) and right vastus lateralis (VLM) muscles of young team sports athletes, using volume (VC) and surface (SC) coils on a 3 T scanner, with the same receiver gain. Water spectra were used as internal reference for the absolute quantification of carnosine. RESULTS Phantom's experiments showed a maximum error of 7%, highlighting the validity of the measurements in the study setup. The carnosine concentrations (mmol/kg ww, mean ± SD) measured in the GM were 6.8 ± 2.2 with the VC (CcarVC) and 10.2 ± 3.0 with the SC (CcarSC) (P = 0.013; n = 9). Therefore, a correction was applied to these measurements (CcarVC = 0.6582*CcarSC), to make coils performance comparable (6.8 ± 2.2 for VC and 6.7 ± 2.0 for SC, P = 0.97). After that, only the SC was used to quantify carnosine in the VLM, where a concentration of 5.4 ± 1.5 (n = 30) was found, with significant differences between men (6.2 ± 1.3; n = 15) and women (4.6 ± 1.2; n = 15). The error in quantitation was 5.3-5.5% with both coils. CONCLUSION The method using the SC and water as internal reference can be used to quantify carnosine in voluminous muscles and regions of the body in humans, where the VC is not suitable, such as the VLM.
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Affiliation(s)
- Gloria Vega
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia
| | - Germán Ricaurte
- Group of Biophysics, University of Antioquia, Medellín, Colombia
| | - Mauricio Estrada-Castrillón
- Pablo Tobón Uribe Hospital, Medellín, Colombia.,Group of Sports Medicine GRINMADE, Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Harmen Reyngoudt
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | | | - Jaime A Gallo-Villegas
- Group of Sports Medicine GRINMADE, Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Raul Narvaez-Sanchez
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia
| | - Juan C Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia.
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Tomiyasu M, Harada M. In vivo Human MR Spectroscopy Using a Clinical Scanner: Development, Applications, and Future Prospects. Magn Reson Med Sci 2022; 21:235-252. [PMID: 35173095 PMCID: PMC9199975 DOI: 10.2463/mrms.rev.2021-0085] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
MR spectroscopy (MRS) is a unique and useful method for noninvasively evaluating biochemical metabolism in human organs and tissues, but its clinical dissemination has been slow and often limited to specialized institutions or hospitals with experts in MRS technology. The number of 3-T clinical MR scanners is now increasing, representing a major opportunity to promote the use of clinical MRS. In this review, we summarize the theoretical background and basic knowledge required to understand the results obtained with MRS and introduce the general consensus on the clinical utility of proton MRS in routine clinical practice. In addition, we present updates to the consensus guidelines on proton MRS published by the members of a working committee of the Japan Society of Magnetic Resonance in Medicine in 2013. Recent research into multinuclear MRS equipped in clinical MR scanners is explained with an eye toward future development. This article seeks to provide an overview of the current status of clinical MRS and to promote the understanding of when it can be useful. In the coming years, MRS-mediated biochemical evaluation is expected to become available for even routine clinical practice.
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Affiliation(s)
- Moyoko Tomiyasu
- Department of Molecular Imaging and Theranostics, National Institutes for Quantum Science and Technology.,Department of Radiology, Kanagawa Children's Medical Center
| | - Masafumi Harada
- Department of Radiology and Radiation Oncology, Graduate School of Biomedical Sciences, Tokushima University
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Marjańska M, Deelchand DK, Kreis R. Results and interpretation of a fitting challenge for MR spectroscopy set up by the MRS study group of ISMRM. Magn Reson Med 2022; 87:11-32. [PMID: 34337767 PMCID: PMC8616800 DOI: 10.1002/mrm.28942] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/25/2021] [Accepted: 07/06/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE Fitting of MRS data plays an important role in the quantification of metabolite concentrations. Many different spectral fitting packages are used by the MRS community. A fitting challenge was set up to allow comparison of fitting methods on the basis of performance and robustness. METHODS Synthetic data were generated for 28 datasets. Short-echo time PRESS spectra were simulated using ideal pulses for the common metabolites at mostly near-normal brain concentrations. Macromolecular contributions were also included. Modulations of signal-to-noise ratio (SNR); lineshape type and width; concentrations of γ-aminobutyric acid, glutathione, and macromolecules; and inclusion of artifacts and lipid signals to mimic tumor spectra were included as challenges to be coped with. RESULTS Twenty-six submissions were evaluated. Visually, most fit packages performed well with mostly noise-like residuals. However, striking differences in fit performance were found with bias problems also evident for well-known packages. In addition, often error bounds were not appropriately estimated and deduced confidence limits misleading. Soft constraints as used in LCModel were found to substantially influence the fitting results and their dependence on SNR. CONCLUSIONS Substantial differences were found for accuracy and precision of fit results obtained by the multiple fit packages.
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Affiliation(s)
- Małgorzata Marjańska
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - Dinesh K. Deelchand
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - Roland Kreis
- Magnetic Resonance Methodology group of the University Institute for Diagnostic and Interventional Neuroradiology and the Department of Biomedical Research, University Bern, Switzerland
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Borbath T, Murali-Manohar S, Dorst J, Wright AM, Henning A. ProFit-1D-A 1D fitting software and open-source validation data sets. Magn Reson Med 2021; 86:2910-2929. [PMID: 34390031 DOI: 10.1002/mrm.28941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 11/05/2022]
Abstract
PURPOSE Accurate and precise MRS fitting is crucial for metabolite concentration quantification of 1 H-MRS spectra. LCModel, a spectral fitting software, has shown to have certain limitations to perform advanced spectral fitting by previous literature. Herein, we propose an open-source spectral fitting algorithm with adaptive spectral baseline determination and more complex cost functions. THEORY The MRS spectra are characterized by several parameters, which reflect the environment of the contributing metabolites, properties of the acquisition sequence, or additional disturbances. Fitting parameters should accurately describe these parameters. Baselines are also a major contributor to MRS spectra, in which smoothness of the spline baselines used for fitting can be adjusted based on the properties of the spectra. Three different cost functions used for the minimization problem were also investigated. METHODS The newly developed ProFit-1D fitting algorithm is systematically evaluated for simulations of several types of possible in vivo parameter variations. Although accuracy and precision are tested with simulated spectra, spectra measured in vivo at 9.4 T are used for testing precision using subsets of averages. ProFit-1D fitting results are also compared with LCModel. RESULTS Both ProFit-1D and LCModel fitted the spectra well with induced parameter and baseline variations. ProFit-1D proved to be more accurate than LCModel for simulated spectra. However, LCModel showed a somewhat increased precision for some spectral simulations and for in vivo data. CONCLUSION The open-source ProFit-1D fitting algorithm demonstrated high accuracy while maintaining precise metabolite concentration quantification. Finally, through the newly proposed cost functions, new ways to improve fitting were shown.
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Affiliation(s)
- Tamas Borbath
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Saipavitra Murali-Manohar
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Johanna Dorst
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive & Systems Neuroscience, Tübingen, Germany
| | - Andrew Martin Wright
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive & Systems Neuroscience, Tübingen, Germany
| | - Anke Henning
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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Coil Combination of Multichannel Single Voxel Magnetic Resonance Spectroscopy with Repeatedly Sampled In Vivo Data. Molecules 2021; 26:molecules26133896. [PMID: 34202302 PMCID: PMC8272065 DOI: 10.3390/molecules26133896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 12/01/2022] Open
Abstract
Magnetic resonance spectroscopy (MRS), as a noninvasive method for molecular structure determination and metabolite detection, has grown into a significant tool in clinical applications. However, the relatively low signal-to-noise ratio (SNR) limits its further development. Although the multichannel coil and repeated sampling are commonly used to alleviate this problem, there is still potential room for promotion. One possible improvement way is combining these two acquisition methods so that the complementary of them can be well utilized. In this paper, a novel coil-combination method, average smoothing singular value decomposition, is proposed to further improve the SNR by introducing repeatedly sampled signals into multichannel coil combination. Specifically, the sensitivity matrix of each sampling was pretreated by whitened singular value decomposition (WSVD), then the smoothing was performed along the repeated samplings’ dimension. By comparing with three existing popular methods, Brown, WSVD, and generalized least squares, the proposed method showed better performance in one phantom and 20 in vivo spectra.
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11
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Petrov OV, Lang J, Vogel M. Exploring the potential of PCA-based quantitation of NMR signals in T 1 relaxometry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 326:106965. [PMID: 33774383 DOI: 10.1016/j.jmr.2021.106965] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/09/2021] [Accepted: 03/14/2021] [Indexed: 06/12/2023]
Abstract
Principal component analysis (PCA) has proved to be a powerful technique for processing NMR data. It is particularly useful in signal quantitation where it often provides better results compared to a direct integration of individual signals. In the present work, we recapitulate the principles and theoretical framework underlying PCA-based quantitation with a special focus on T1 relaxometry. We show that under commonly encountered conditions, this approach can provide up to ~4-fold improvement in scatter of points in magnetization build-up curves compared to direct integration. Best practices to optimize the PCA performance in measuring the total magnetization are discussed, including minimization of the number of signal-related principal components and a proper selection of FT parameters and data quantitation intervals. For signals consisting of distinct relaxation components, formulas are provided for resolving the components relaxation and illustrated on a real-data example. In addition to the problem of quantitation, the use of PCA in denoising of partially relaxed spectra is discussed in connection with such applications as line shape analysis and monitoring relaxation of individual spectral components.
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Affiliation(s)
- Oleg V Petrov
- Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 747/2, 180 00 Prague 8, Czech Republic.
| | - Jan Lang
- Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 747/2, 180 00 Prague 8, Czech Republic
| | - Michael Vogel
- Institute for Condensed Matter Physics, Technical University of Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
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Maudsley AA, Andronesi OC, Barker PB, Bizzi A, Bogner W, Henning A, Nelson SJ, Posse S, Shungu DC, Soher BJ. Advanced magnetic resonance spectroscopic neuroimaging: Experts' consensus recommendations. NMR IN BIOMEDICINE 2021; 34:e4309. [PMID: 32350978 PMCID: PMC7606742 DOI: 10.1002/nbm.4309] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 02/01/2020] [Accepted: 03/10/2020] [Indexed: 05/04/2023]
Abstract
Magnetic resonance spectroscopic imaging (MRSI) offers considerable promise for monitoring metabolic alterations associated with disease or injury; however, to date, these methods have not had a significant impact on clinical care, and their use remains largely confined to the research community and a limited number of clinical sites. The MRSI methods currently implemented on clinical MRI instruments have remained essentially unchanged for two decades, with only incremental improvements in sequence implementation. During this time, a number of technological developments have taken place that have already greatly benefited the quality of MRSI measurements within the research community and which promise to bring advanced MRSI studies to the point where the technique becomes a true imaging modality, while making the traditional review of individual spectra a secondary requirement. Furthermore, the increasing use of biomedical MR spectroscopy studies has indicated clinical areas where advanced MRSI methods can provide valuable information for clinical care. In light of this rapidly changing technological environment and growing understanding of the value of MRSI studies for biomedical studies, this article presents a consensus from a group of experts in the field that reviews the state-of-the-art for clinical proton MRSI studies of the human brain, recommends minimal standards for further development of vendor-provided MRSI implementations, and identifies areas which need further technical development.
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Affiliation(s)
- Andrew A Maudsley
- Department of Radiology, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Ovidiu C Andronesi
- Department of Radiology, Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Boston, Massachusetts
| | - Peter B Barker
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, and the Kennedy Krieger Institute, F.M. Kirby Center for Functional Brain Imaging, Baltimore, Maryland
| | - Alberto Bizzi
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Anke Henning
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sarah J Nelson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California
| | - Stefan Posse
- Department of Neurology, University of New Mexico, Albuquerque, New Mexico
| | - Dikoma C Shungu
- Department of Neuroradiology, Weill Cornell Medical College, New York, New York
| | - Brian J Soher
- Department of Radiology, Duke University Medical Center, Durham, North Carolina
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Zöllner HJ, Považan M, Hui SC, Tapper S, Edden RA, Oeltzschner G. Comparison of different linear-combination modeling algorithms for short-TE proton spectra. NMR IN BIOMEDICINE 2021; 34:e4482. [PMID: 33530131 PMCID: PMC8935349 DOI: 10.1002/nbm.4482] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/09/2021] [Indexed: 05/08/2023]
Abstract
Short-TE proton MRS is used to study metabolism in the human brain. Common analysis methods model the data as a linear combination of metabolite basis spectra. This large-scale multi-site study compares the levels of the four major metabolite complexes in short-TE spectra estimated by three linear-combination modeling (LCM) algorithms. 277 medial parietal lobe short-TE PRESS spectra (TE = 35 ms) from a recent 3 T multi-site study were preprocessed with the Osprey software. The resulting spectra were modeled with Osprey, Tarquin and LCModel, using the same three vendor-specific basis sets (GE, Philips and Siemens) for each algorithm. Levels of total N-acetylaspartate (tNAA), total choline (tCho), myo-inositol (mI) and glutamate + glutamine (Glx) were quantified with respect to total creatine (tCr). Group means and coefficient of variations of metabolite estimates agreed well for tNAA and tCho across vendors and algorithms, but substantially less so for Glx and mI, with mI systematically estimated as lower by Tarquin. The cohort mean coefficient of determination for all pairs of LCM algorithms across all datasets and metabolites was R 2 ¯ = 0.39, indicating generally only moderate agreement of individual metabolite estimates between algorithms. There was a significant correlation between local baseline amplitude and metabolite estimates (cohort mean R 2 ¯ = 0.10). While mean estimates of major metabolite complexes broadly agree between linear-combination modeling algorithms at group level, correlations between algorithms are only weak-to-moderate, despite standardized preprocessing, a large sample of young, healthy and cooperative subjects, and high spectral quality. These findings raise concerns about the comparability of MRS studies, which typically use one LCM software and much smaller sample sizes.
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Affiliation(s)
- Helge J. Zöllner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Michal Považan
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Steve C.N. Hui
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Sofie Tapper
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Richard A.E. Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Georg Oeltzschner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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14
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Froeling M, Prompers JJ, Klomp DWJ, van der Velden TA. PCA denoising and Wiener deconvolution of 31 P 3D CSI data to enhance effective SNR and improve point spread function. Magn Reson Med 2021; 85:2992-3009. [PMID: 33522635 PMCID: PMC7986807 DOI: 10.1002/mrm.28654] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/10/2020] [Accepted: 12/01/2020] [Indexed: 12/19/2022]
Abstract
Purpose This study evaluates the performance of 2 processing methods, that is, principal component analysis‐based denoising and Wiener deconvolution, to enhance the quality of phosphorus 3D chemical shift imaging data. Methods Principal component analysis‐based denoising increases the SNR while maintaining spectral information. Wiener deconvolution reduces the FWHM of the voxel point spread function, which is increased by Hamming filtering or Hamming‐weighted acquisition. The proposed methods are evaluated using simulated and in vivo 3D phosphorus chemical shift imaging data by 1) visual inspection of the spatial signal distribution; 2) SNR calculation of the PCr peak; and 3) fitting of metabolite basis functions. Results With the optimal order of processing steps, we show that the effective SNR of in vivo phosphorus 3D chemical shift imaging data can be increased. In simulations, we show we can preserve phosphorus‐containing metabolite peaks that had an SNR < 1 before denoising. Furthermore, using Wiener deconvolution, we were able to reduce the FWHM of the voxel point spread function with only partially reintroducing Gibb‐ringing artifacts while maintaining the SNR. After data processing, fitting of the phosphorus‐containing metabolite signals improved. Conclusion In this study, we have shown that principal component analysis‐based denoising in combination with regularized Wiener deconvolution allows increasing the effective spectral SNR of in vivo phosphorus 3D chemical shift imaging data, with reduction of the FWHM of the voxel point spread function. Processing increased the effective SNR by at least threefold compared to Hamming weighted acquired data and minimized voxel bleeding. With these methods, fitting of metabolite amplitudes became more robust with decreased fitting residuals.
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Affiliation(s)
- Martijn Froeling
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tijl A van der Velden
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
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15
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Nosrati R, Balasubramanian M, Mulkern R. Measuring transverse relaxation rates of the major brain metabolites from single-voxel PRESS acquisitions at a single TE. Magn Reson Med 2021; 85:2965-2977. [PMID: 33404069 DOI: 10.1002/mrm.28644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/21/2020] [Accepted: 11/24/2020] [Indexed: 11/08/2022]
Abstract
PURPOSE To compare transverse relaxation rates of brain metabolites estimated from single-TE PRESS acquisitions with more conventionally derived rates estimated from multiple-TE PRESS acquisitions. METHODS Single-voxel (8 mL) PRESS data within white matter from 6 subjects were acquired at five different TEs. Transverse relaxation rates R2 of N-acetylaspartate, creatine, and choline were estimated from a single TE using full versus right-side-only sampling of the echo. These R2 values were compared with R2Hahn values obtained from the multiple-TE PRESS acquisitions. RESULTS Following baseline subtraction and RMS weighting, interindividual mean R2 values from TE = 288 ms magnitude spectra for choline, creatine, and N-acetylaspartate were highly correlated with respective R2Hahn values (r2 = 0.99). Paired individual measurements at this TE showed less correlation (r2 = 0.48), primarily due to the N-acetylaspartate resonance. Using TE = 360 ms data for N-acetylaspartate and 288 ms for choline and creatine resulted in an improved correlation coefficient (r2 = 0.80). The average absolute intra-individual differences in the estimated R2 s between single-TE and Hahn method was 9.6 ± 7.7%. CONCLUSION For the major brain metabolite singlets, R2Hahn values showed correlations with more fragile measurements of R2 from a single TE that are worthy of interest. Because the left side of long-TE spin echoes is available "for free" from an acquisition perspective, and although the single-TE method for estimating R2 values is associated with lower precision, the reduction in scan time may be clinically helpful.
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Affiliation(s)
- Reyhaneh Nosrati
- Radiology Department, Boston Children's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Mukund Balasubramanian
- Radiology Department, Boston Children's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Robert Mulkern
- Radiology Department, Boston Children's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
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16
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Peterson P, Trinh L, Månsson S. Quantitative 1 H MRI and MRS of fatty acid composition. Magn Reson Med 2020; 85:49-67. [PMID: 32844500 DOI: 10.1002/mrm.28471] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/08/2020] [Accepted: 07/20/2020] [Indexed: 12/22/2022]
Abstract
Adipose tissue as well as other depots of fat (triglycerides) are increasingly being recognized as active contributors to the human function and metabolism. In addition to the fat concentration, also the fatty acid chemical composition (FAC) of the triglyceride molecules may play an important part in diseases such as obesity, insulin resistance, hepatic steatosis, osteoporosis, and cancer. MR spectroscopy and chemical-shift-encoded imaging (CSE-MRI) are established methods for non-invasive quantification of fat concentration in tissue. More recently, similar techniques have been developed for assessment also of the FAC in terms of the number of double bonds, the fraction of saturated, monounsaturated, and polyunsaturated fatty acids, or semi-quantitative unsaturation indices. The number of papers focusing on especially CSE-MRI-based techniques has steadily increased during the past few years, introducing a range of acquisition protocols and reconstruction algorithms. However, a number of potential sources of bias have also been identified. Furthermore, the measures used to characterize the FAC using both MRI and MRS differ, making comparisons between different techniques difficult. The aim of this paper is to review MRS- and MRI-based methods for in vivo quantification of the FAC. We describe the chemical composition of triglycerides and discuss various potential FAC measures. Furthermore, we review acquisition and reconstruction methodology and finally, some existing and potential applications are summarized. We conclude that both MRI and MRS provide feasible non-invasive alternatives to the gold standard gas chromatography for in vivo measurements of the FAC. Although both are associated with gas chromatography, future studies are warranted.
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Affiliation(s)
- Pernilla Peterson
- Medical Radiation Physics, Malmö, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.,Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - Lena Trinh
- Medical Radiation Physics, Malmö, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Sven Månsson
- Medical Radiation Physics, Malmö, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
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17
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Matviychuk Y, Steimers E, von Harbou E, Holland D. Improving the accuracy of model-based quantitative nuclear magnetic resonance. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2020; 1:141-153. [PMID: 37904816 PMCID: PMC10500698 DOI: 10.5194/mr-1-141-2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/30/2020] [Indexed: 11/01/2023]
Abstract
Low spectral resolution and extensive peak overlap are the common challenges that preclude quantitative analysis of nuclear magnetic resonance (NMR) data with the established peak integration method. While numerous model-based approaches overcome these obstacles and enable quantification, they intrinsically rely on rigid assumptions about functional forms for peaks, which are often insufficient to account for all unforeseen imperfections in experimental data. Indeed, even in spectra with well-separated peaks whose integration is possible, model-based methods often achieve suboptimal results, which in turn raises the question of their validity for more challenging datasets. We address this problem with a simple model adjustment procedure, which draws its inspiration directly from the peak integration approach that is almost invariant to lineshape deviations. Specifically, we assume that the number of mixture components along with their ideal spectral responses are known; we then aim to recover all useful signals left in the residual after model fitting and use it to adjust the intensity estimates of modelled peaks. We propose an alternative objective function, which we found particularly effective for correcting imperfect phasing of the data - a critical step in the processing pipeline. Application of our method to the analysis of experimental data shows the accuracy improvement of 20 %-40 % compared to the simple least-squares model fitting.
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Affiliation(s)
- Yevgen Matviychuk
- Department of Chemical and Process Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Ellen Steimers
- Lehrstuhl für Thermodynamik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 44, Kaiserslautern 67663, Germany
| | - Erik von Harbou
- Lehrstuhl für Thermodynamik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 44, Kaiserslautern 67663, Germany
- current address: BASF SE, Research and Development, Ludwigshafen, Germany
| | - Daniel J. Holland
- Department of Chemical and Process Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
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18
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Goryawala M, Sullivan M, Maudsley AA. Effects of apodization smoothing and denoising on spectral fitting. Magn Reson Imaging 2020; 70:108-114. [PMID: 32333950 DOI: 10.1016/j.mri.2020.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/13/2020] [Accepted: 04/19/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE Visual review of individual spectra in magnetic resonance spectroscopic imaging (MRSI) data benefits from the application of spectral smoothing; however, if this processing step is applied prior to spectral analysis this can impact the accuracy of the quantitation. This study aims to analyze the effect of spectral denoising and apodization smoothing on the quantitation of whole-brain MRSI data obtained at short TE. METHODS Short-TE MRSI data obtained at 3 T were analyzed with no spectral smoothing, following (i) Gaussian apodization with values of 1, 2, 4, 6, and 8 Hz, and (ii) denoising using principal component analysis (dnPCA) with 3 different values for the number of retained principal components. The mean lobar white matter estimates for four metabolites, signal-to-noise ratio (SNR), spectral linewidth, and confidence intervals were compared to data reconstructed using no smoothing. Additionally, a voxel-wise comparison for N-acetylaspartate quantitation with different smoothing schemes was performed. RESULTS Significant pairwise differences were seen for all Gaussian smoothing methods as compared to no smoothing (p<0.001) in linewidth and metabolite estimates, whereas dnPCA methods showing no statistically significant differences in these measures. Confidence intervals decreased, and SNR increased with increasing levels of apodization smoothing or dnPCA denoising. CONCLUSION Mild Gaussian apodization (≤2 Hz at 3 T) can be applied with minimal (1%) errors in quantitation; however, smoothing values greater than that can significantly affect metabolite quantification. In contrast, mild to moderate dnPCA based denoising provides quantitative results that are consistent with the analysis of unsmoothed data and this method is recommended for spectral denoising.
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Affiliation(s)
| | - Molly Sullivan
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA
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19
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Öz G, Deelchand DK, Wijnen JP, Mlynárik V, Xin L, Mekle R, Noeske R, Scheenen TWJ, Tkáč I. Advanced single voxel 1 H magnetic resonance spectroscopy techniques in humans: Experts' consensus recommendations. NMR IN BIOMEDICINE 2020; 34:e4236. [PMID: 31922301 PMCID: PMC7347431 DOI: 10.1002/nbm.4236] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/29/2019] [Accepted: 11/07/2019] [Indexed: 05/06/2023]
Abstract
Conventional proton MRS has been successfully utilized to noninvasively assess tissue biochemistry in conditions that result in large changes in metabolite levels. For more challenging applications, namely, in conditions which result in subtle metabolite changes, the limitations of vendor-provided MRS protocols are increasingly recognized, especially when used at high fields (≥3 T) where chemical shift displacement errors, B0 and B1 inhomogeneities and limitations in the transmit B1 field become prominent. To overcome the limitations of conventional MRS protocols at 3 and 7 T, the use of advanced MRS methodology, including pulse sequences and adjustment procedures, is recommended. Specifically, the semiadiabatic LASER sequence is recommended when TE values of 25-30 ms are acceptable, and the semiadiabatic SPECIAL sequence is suggested as an alternative when shorter TE values are critical. The magnetic field B0 homogeneity should be optimized and RF pulses should be calibrated for each voxel. Unsuppressed water signal should be acquired for eddy current correction and preferably also for metabolite quantification. Metabolite and water data should be saved in single shots to facilitate phase and frequency alignment and to exclude motion-corrupted shots. Final averaged spectra should be evaluated for SNR, linewidth, water suppression efficiency and the presence of unwanted coherences. Spectra that do not fit predefined quality criteria should be excluded from further analysis. Commercially available tools to acquire all data in consistent anatomical locations are recommended for voxel prescriptions, in particular in longitudinal studies. To enable the larger MRS community to take advantage of these advanced methods, a list of resources for these advanced protocols on the major clinical platforms is provided. Finally, a set of recommendations are provided for vendors to enable development of advanced MRS on standard platforms, including implementation of advanced localization sequences, tools for quality assurance on the scanner, and tools for prospective volume tracking and dynamic linear shim corrections.
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Affiliation(s)
- Gülin Öz
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, United States
| | - Dinesh K. Deelchand
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, United States
| | - Jannie P. Wijnen
- High field MR Research group, Department of Radiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Vladimír Mlynárik
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Lijing Xin
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ralf Mekle
- Center for Stroke Research Berlin (CSB), Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Tom W. J. Scheenen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
- Erwin L Hahn Institute for Magnetic Resonance Imaging, UNESCO World Cultural Heritage Zollverein, Essen, Germany
| | - Ivan Tkáč
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, United States
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20
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Matviychuk Y, Yeo J, Holland DJ. A field-invariant method for quantitative analysis with benchtop NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 298:35-47. [PMID: 30529048 DOI: 10.1016/j.jmr.2018.11.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Recently developed benchtop instruments have the potential of bringing the benefits of NMR spectroscopy to the wide variety of industrial applications. Unfortunately, their low spectral resolution poses significant challenges for traditional quantification approach. Here we present a novel model-based method designed to overcome these challenges. By defining our models in terms of quantum mechanical properties of the underlying spin system, we make our approach invariant to the spectrometer field strength and especially suitable for analyzing benchtop data. Our experimental results on prepared samples and natural fruit juices confirm the applicability of our method for quantitative analysis of medium-field 1H NMR spectra. The developed method succeeds in accurately separating the spectra of glucose anomers and even monitoring their interconversion in non-deuterated water. Furthermore, the compositions of unbuffered natural fruit juices estimated using data from 43 MHz to 400 MHz spectrometers are in good agreement with each other and with the reference values from nutrition databases.
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Affiliation(s)
- Yevgen Matviychuk
- University of Canterbury, Private Bag 4800, Cristchurch 8140, New Zealand
| | - Jet Yeo
- University of Canterbury, Private Bag 4800, Cristchurch 8140, New Zealand
| | - Daniel J Holland
- University of Canterbury, Private Bag 4800, Cristchurch 8140, New Zealand.
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21
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Wenger KJ, Hattingen E, Harter PN, Richter C, Franz K, Steinbach JP, Bähr O, Pilatus U. Fitting algorithms and baseline correction influence the results of non-invasive in vivo quantitation of 2-hydroxyglutarate with 1 H-MRS. NMR IN BIOMEDICINE 2019; 32:e4027. [PMID: 30457203 DOI: 10.1002/nbm.4027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 06/09/2023]
Abstract
1 H-MRS enables non-invasive detection of 2-hydroxyglutarate (2-HG), an oncometabolite accumulating in gliomas carrying mutations in the isocitrate dehydrogenase (IDH) genes. Reliable 2-HG quantitation requires reproducible post-processing, deployment of fitting algorithms and quantitation methods. We prospectively enrolled 38 patients with suspected or recently diagnosed gliomas (IDH mutated n = 26). The MRI protocol included a 1 H single voxel PRESS sequence with volumes of usually 8 mL or more (20 × 20 × 20 mm3 ) at TE = 97 ms and 180° pulse spacing. Our aim was to evaluate the reliability of 2-HG quantitation comparing two frequently used software tools and their respective options of baseline correction (jMRUI with the time domain methods AQSES and QUEST, and LCModel, which analyzes the frequency domain data). For AQSES, degrees of freedom for baseline correction constrains were varied. For LCModel, baseline correction was obtained with and without correction of the unknown background term (predefined macromolecules, lipids). Tissue concentrations were calculated based on the phantom replacement method. Quantitation of 2-HG levels showed similar mean 2-HG tissue concentrations for IDH mutated tumors (2.65mM, range 3.06-2.20) for all methods. Bland-Altman plots (difference plots) did not reveal a systematic bias (fixed bias) for any of the algorithms tested, and we were able to show a significant correlation regarding 2-HG concentration at the same echo time with few statistical outliers (parametric correlation). However, evaluation of outliers suggested that in vivo quantitation of 2-HG is affected not only by the fitting domain (time or frequency), but also by the baseline correction, which is a major contributing factor to the result of 2-HG fitting. Clinical application of 2-HG quantitation as a prognostic or predictive biomarker, particularly in multicenter trials, requires standardized use of fitting methods and baseline correction procedures.
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Affiliation(s)
- Katharina J Wenger
- Klinikum der Johann Wolfgang Goethe-Universitat Frankfurt, Senckenberg Institute of Neurooncology, Frankfurt, Germany
| | - Elke Hattingen
- Universitatsklinikum Bonn, Institute of Neuroradiology, Bonn, Germany
| | - Patrick N Harter
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Edinger Institute, Neuropathology, Frankfurt, Germany
| | - Christian Richter
- Goethe Universität Frankfurt am Main, Organic Chemistry, Schwalbe Group, Frankfurt, Germany
| | - Kea Franz
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Institute of Neurosurgery, Frankfurt, Germany
| | - Joachim P Steinbach
- Klinikum der Johann Wolfgang Goethe-Universitat Frankfurt, Senckenberg Institute of Neurooncology, Frankfurt, Germany
| | - Oliver Bähr
- Klinikum der Johann Wolfgang Goethe-Universitat Frankfurt, Senckenberg Institute of Neurooncology, Frankfurt, Germany
| | - Ulrich Pilatus
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Institute of Neuroradiology, Frankfurt, Germany
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Anjum MAR, Dmochowski PA, Teal PD. A subband Steiglitz-McBride algorithm for automatic analysis of FID data. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:740-747. [PMID: 29473217 DOI: 10.1002/mrc.4723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/31/2018] [Accepted: 02/03/2018] [Indexed: 06/08/2023]
Abstract
Fast, accurate, and automatic extraction of parameters of nuclear magnetic resonance free induction decay (FID) signal for chemical spectroscopy is a challenging problem. Recently, the Steiglitz-McBride algorithm has been shown to exhibit superior performance in terms of speed, accuracy, and automation when applied to the extraction of T2 relaxation parameters for myelin water imaging of brain. Applying it to FID data reveals that it falls short of the second objective, the accuracy. Especially, it struggles with the issue of missed spectral peaks when applied to chemical samples with relatively dense frequency spectra. To overcome this issue, a preprocessing stage of subband decomposition is proposed before the application of Steiglitz-McBride algorithm to the FID signal. It is demonstrated that by doing so, a considerable improvement in accuracy is achieved. But this is not gained at the cost of the first objective, the speed. An adaptive subband decomposition is employed in conjunction with the Bayesian information criteria to carry out an efficient decomposition according to spectral content of the signal under investigation. Furthermore, adaptive subband decomposition and the Bayesian information criteria also serve to make the resulting algorithm independent of user input, which also fulfills the third objective, the automation. This makes the proposed algorithm favorable for fast, accurate, and automatic extraction of FID signal parameters.
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Affiliation(s)
- M A R Anjum
- School of Engineering and Computer Science, Victoria University of Wellington, Wellington, 6140, New Zealand
| | - Pawel A Dmochowski
- School of Engineering and Computer Science, Victoria University of Wellington, Wellington, 6140, New Zealand
| | - Paul D Teal
- School of Engineering and Computer Science, Victoria University of Wellington, Wellington, 6140, New Zealand
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23
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Semiblind Spectral Factorization Approach for Magnetic Resonance Spectroscopy Quantification. IEEE Trans Biomed Eng 2018; 65:1717-1724. [DOI: 10.1109/tbme.2017.2770088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Matviychuk Y, von Harbou E, Holland DJ. An experimental validation of a Bayesian model for quantification in NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 285:86-100. [PMID: 29127944 DOI: 10.1016/j.jmr.2017.10.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/20/2017] [Accepted: 10/21/2017] [Indexed: 06/07/2023]
Abstract
The traditional peak integration method for quantitative analysis in nuclear magnetic resonance (NMR) spectroscopy is inherently limited by its ability to resolve overlapping peaks and is susceptible to noise. The alternative model-based approaches not only extend quantification capabilities to these challenging examples but also provide a means for automation of the entire process of NMR data analysis. In this paper, we present a general model for an NMR signal that, in a principled way, takes into account the effects of chemical shifts, relaxation, lineshape imperfections, phasing, and baseline distortions. We test the model using both simulations and experiments, concentrating on simple spectra with well-resolved peaks where we expect conventional analysis to be effective. Our results of quantifying mixture compositions compare favorably with the established methods. At high SNR (>40dB), all approaches usually achieve for these test systems an absolute accuracy of at least 0.01mol/mol for the concentrations of all species. Our model-based approach is successful even for SNR<20dB; it achieves 0.05-0.1mol/mol accuracy in cases where precise phasing is practically impossible due to high levels of noise in the data.
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Affiliation(s)
- Yevgen Matviychuk
- University of Canterbury, Private Bag 4800, Cristchurch 8140, New Zealand.
| | - Erik von Harbou
- Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 44, 67663 Kaiserslautern, Germany
| | - Daniel J Holland
- University of Canterbury, Private Bag 4800, Cristchurch 8140, New Zealand
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25
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Bhogal AA, Schür RR, Houtepen LC, van de Bank B, Boer VO, Marsman A, Barker PB, Scheenen TWJ, Wijnen JP, Vinkers CH, Klomp DWJ. 1 H-MRS processing parameters affect metabolite quantification: The urgent need for uniform and transparent standardization. NMR IN BIOMEDICINE 2017; 30:e3804. [PMID: 28915314 DOI: 10.1002/nbm.3804] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
Proton magnetic resonance spectroscopy (1 H-MRS) can be used to quantify in vivo metabolite levels, such as lactate, γ-aminobutyric acid (GABA) and glutamate (Glu). However, there are considerable analysis choices which can alter the accuracy or precision of 1 H-MRS metabolite quantification. It is currently unknown to what extent variations in the analysis pipeline used to quantify 1 H-MRS data affect outcomes. The purpose of this study was to evaluate whether the quantification of identical 1 H-MRS scans across independent and experienced research groups would yield comparable results. We investigated the influence of model parameters and spectral quantification software on fitted metabolite concentration values. Sixty spectra in 30 individuals (repeated measures) were acquired using a 7-T MRI scanner. Data were processed by four independent research groups with the freedom to choose their own individualized and optimal parameter settings using LCModel software. Data were processed a second time in one group using an independent software package (NMRWizard) for an additional comparison with a different post-processing platform. Correlations across research groups of the ratio between the highest and, arguably, the most relevant resonances for neurotransmission [N-acetyl aspartate (NAA), N-acetyl aspartyl glutamate (NAAG) and Glu] over the total creatine [creatine (Cr) + phosphocreatine (PCr)] concentration, using Pearson's product-moment correlation coefficient (r), were calculated. Mean inter-group correlations using LCModel software were 0.87, 0.88 and 0.77 for NAA/Cr + PCr, NAA + NAAG/Cr + PCr and Glu/Cr + PCr, respectively. The mean correlations when comparing NMRWizard results with LCModel fitting results at University Medical Center Utrecht (UMCU) were 0.87, 0.89 and 0.71 for NAA/Cr + PCr, NAA + NAAG/Cr + PCr and Glu/Cr + PCr, respectively. Metabolite quantification using identical 1 H-MRS data was influenced by processing parameters, basis sets and software choice. Locally preferred processing choices affected metabolite quantification, even when using identical software. Our results reinforce the notion that standard practices should be established to regularize outcomes of 1 H-MRS studies, and that basis sets used for processing should be made available to the scientific community.
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Affiliation(s)
- Alex A Bhogal
- Radiology Department, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Remmelt R Schür
- Psychiatry Department, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Lotte C Houtepen
- Psychiatry Department, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Bart van de Bank
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Vincent O Boer
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Anouk Marsman
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Peter B Barker
- Department of Radiology and Radiological Science - Neuroradiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tom W J Scheenen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jannie P Wijnen
- Radiology Department, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Christiaan H Vinkers
- Psychiatry Department, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Dennis W J Klomp
- Radiology Department, University Medical Center Utrecht, Utrecht, the Netherlands
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Purvis LAB, Clarke WT, Biasiolli L, Valkovič L, Robson MD, Rodgers CT. OXSA: An open-source magnetic resonance spectroscopy analysis toolbox in MATLAB. PLoS One 2017; 12:e0185356. [PMID: 28938003 PMCID: PMC5609763 DOI: 10.1371/journal.pone.0185356] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/11/2017] [Indexed: 01/17/2023] Open
Abstract
In vivo magnetic resonance spectroscopy provides insight into metabolism in the human body. New acquisition protocols are often proposed to improve the quality or efficiency of data collection. Processing pipelines must also be developed to use these data optimally. Current fitting software is either targeted at general spectroscopy fitting, or for specific protocols. We therefore introduce the MATLAB-based OXford Spectroscopy Analysis (OXSA) toolbox to allow researchers to rapidly develop their own customised processing pipelines. The toolbox aims to simplify development by: being easy to install and use; seamlessly importing Siemens Digital Imaging and Communications in Medicine (DICOM) standard data; allowing visualisation of spectroscopy data; offering a robust fitting routine; flexibly specifying prior knowledge when fitting; and allowing batch processing of spectra. This article demonstrates how each of these criteria have been fulfilled, and gives technical details about the implementation in MATLAB. The code is freely available to download from https://github.com/oxsatoolbox/oxsa.
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Affiliation(s)
- Lucian A. B. Purvis
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- * E-mail:
| | - William T. Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Luca Biasiolli
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
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27
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Aboutanios E, Thomas DS, Hook JM, Cobas C. LocMAP: A new localization method for the parametric processing of high resolution NMR data. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 282:62-70. [PMID: 28772254 DOI: 10.1016/j.jmr.2017.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/06/2017] [Accepted: 06/16/2017] [Indexed: 06/07/2023]
Abstract
High resolution NMR spectroscopy offers a large number of data points that enable close peaks to be resolved. Data processing algorithms, however, have not yet been able to capitalize on this offering to achieve the highest permissible resolution. Although singular value decomposition (SVD) based methods such as matrix pencil (MPM) are theoretically able to achieve this, their onerous computational cost makes them impractical. In this work, we address this problem and propose a localized MPM method that we refer to as LocMaP, which is capable of delivering the promised high resolution while at the same time taking advantage of the computational efficiency of the FFT. We present the derivation of LocMaP and offer an efficient implementation of it. Evaluation using both Monte Carlo runs and a simulated FID establish the great potential of the proposed method.
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Affiliation(s)
- Elias Aboutanios
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Donald S Thomas
- NMR Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia.
| | - James M Hook
- NMR Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Carlos Cobas
- Mestrelab Research S.L., Feliciano Barrera, 9, 15706 Santiago de Compostela, Spain.
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28
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Soulsby D, Chica JAM. Determination of partition coefficients using 1 H NMR spectroscopy and time domain complete reduction to amplitude-frequency table (CRAFT) analysis. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:724-729. [PMID: 28181700 DOI: 10.1002/mrc.4582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/02/2017] [Accepted: 02/05/2017] [Indexed: 06/06/2023]
Abstract
We have developed a simple, direct and novel method for the determination of partition coefficients and partitioning behavior using 1 H NMR spectroscopy combined with time domain complete reduction to amplitude-frequency tables (CRAFT). After partitioning into water and 1-octanol using standard methods, aliquots from each layer are directly analyzed using either proton or selective excitation NMR experiments. Signal amplitudes for each compound from each layer are then extracted directly from the time domain data in an automated fashion and analyzed using the CRAFT software. From these amplitudes, log P and log D7.4 values can be calculated directly. Phase, baseline and internal standard issues, which can be problematic when Fourier transformed data are used, are unimportant when using time domain data. Furthermore, analytes can contain impurities because only a single resonance is examined and need not be UV active. Using this approach, we examined a variety of pharmaceutically relevant compounds and determined partition coefficients that are in excellent agreement with literature values. To demonstrate the utility of this approach, we also examined salicylic acid in more detail demonstrating an aggregation effect as a function of sample loading and partition coefficient behavior as a function of pH value. This method provides a valuable addition to the medicinal chemist toolbox for determining these important constants. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- David Soulsby
- Chemistry Department, University of Redlands, 1200 E. Colton Avenue, Redlands, CA, 92374-3755, USA
| | - Jeryl A M Chica
- Chemistry Department, University of Redlands, 1200 E. Colton Avenue, Redlands, CA, 92374-3755, USA
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29
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Lanz B, Rackayova V, Braissant O, Cudalbu C. MRS studies of neuroenergetics and glutamate/glutamine exchange in rats: Extensions to hyperammonemic models. Anal Biochem 2017; 529:245-269. [DOI: 10.1016/j.ab.2016.11.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 11/16/2016] [Accepted: 11/30/2016] [Indexed: 01/27/2023]
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30
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Adalid V, Döring A, Kyathanahally SP, Bolliger CS, Boesch C, Kreis R. Fitting interrelated datasets: metabolite diffusion and general lineshapes. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 30:429-448. [DOI: 10.1007/s10334-017-0618-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/24/2017] [Accepted: 03/27/2017] [Indexed: 12/23/2022]
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31
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García-Figueiras R, Baleato-González S, Padhani AR, Oleaga L, Vilanova JC, Luna A, Cobas Gómez JC. Proton magnetic resonance spectroscopy in oncology: the fingerprints of cancer? Diagn Interv Radiol 2017; 22:75-89. [PMID: 26712681 DOI: 10.5152/dir.2015.15009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Abnormal metabolism is a key tumor hallmark. Proton magnetic resonance spectroscopy (1H-MRS) allows measurement of metabolite concentration that can be utilized to characterize tumor metabolic changes. 1H-MRS measurements of specific metabolites have been implemented in the clinic. This article performs a systematic review of image acquisition and interpretation of 1H-MRS for cancer evaluation, evaluates its strengths and limitations, and correlates metabolite peaks at 1H-MRS with diagnostic and prognostic parameters of cancer in different tumor types.
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Affiliation(s)
- Roberto García-Figueiras
- Department of Radiology, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, Spain.
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32
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Parto Dezfouli MA, Parto Dezfouli M, Ahmadian A, Frangi AF, Esmaeili Rad M, Saligheh Rad H. Quantification of 1 H-MRS signals based on sparse metabolite profiles in the time-frequency domain. NMR IN BIOMEDICINE 2017; 30:e3675. [PMID: 28052436 DOI: 10.1002/nbm.3675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 10/27/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
MRS is an analytical approach used for both quantitative and qualitative analysis of human body metabolites. The accurate and robust quantification capability of proton MRS (1 H-MRS) enables the accurate estimation of living tissue metabolite concentrations. However, such methods can be efficiently employed for quantification of metabolite concentrations only if the overlapping nature of metabolites, existing static field inhomogeneity and low signal-to-noise ratio (SNR) are taken into consideration. Representation of 1 H-MRS signals in the time-frequency domain enables us to handle the baseline and noise better. This is possible because the MRS signal of each metabolite is sparsely represented, with only a few peaks, in the frequency domain, but still along with specific time-domain features such as distinct decay constant associated with T2 relaxation rate. The baseline, however, has a smooth behavior in the frequency domain. In this study, we proposed a quantification method using continuous wavelet transformation of 1 H-MRS signals in combination with sparse representation of features in the time-frequency domain. Estimation of the sparse representations of MR spectra is performed according to the dictionaries constructed from metabolite profiles. Results on simulated and phantom data show that the proposed method is able to quantify the concentration of metabolites in 1 H-MRS signals with high accuracy and robustness. This is achieved for both low SNR (5 dB) and low signal-to-baseline ratio (-5 dB) regimes.
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Affiliation(s)
- Mohammad Ali Parto Dezfouli
- Department of Biomedical Engineering and Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran, Iran
| | - Mohsen Parto Dezfouli
- School of Electrical Engineering, Faculty of Biomedical Engineering, Iran University of Science and Technology, Tehran, Iran
| | - Alireza Ahmadian
- Department of Biomedical Engineering and Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
| | - Alejandro F Frangi
- CISTIB Center for Computational Imaging and Simulation Technologies in Biomedicine, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Melika Esmaeili Rad
- Department of Electrical and Biomedical Engineering, Islamic Azad University of Qazvin, Qazvin, Iran
| | - Hamidreza Saligheh Rad
- Department of Biomedical Engineering and Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran, Iran
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Larsen RJ, Newman M, Nikolaidis A. Reduction of variance in measurements of average metabolite concentration in anatomically-defined brain regions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 272:73-81. [PMID: 27662403 DOI: 10.1016/j.jmr.2016.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 06/06/2023]
Abstract
Multiple methods have been proposed for using Magnetic Resonance Spectroscopy Imaging (MRSI) to measure representative metabolite concentrations of anatomically-defined brain regions. Generally these methods require spectral analysis, quantitation of the signal, and reconciliation with anatomical brain regions. However, to simplify processing pipelines, it is practical to only include those corrections that significantly improve data quality. Of particular importance for cross-sectional studies is knowledge about how much each correction lowers the inter-subject variance of the measurement, thereby increasing statistical power. Here we use a data set of 72 subjects to calculate the reduction in inter-subject variance produced by several corrections that are commonly used to process MRSI data. Our results demonstrate that significant reductions of variance can be achieved by performing water scaling, accounting for tissue type, and integrating MRSI data over anatomical regions rather than simply assigning MRSI voxels with anatomical region labels.
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Affiliation(s)
- Ryan J Larsen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Michael Newman
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States
| | - Aki Nikolaidis
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States
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34
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Lee HH, Kim H. Parameterization of spectral baseline directly from short echo time full spectra in 1
H-MRS. Magn Reson Med 2016; 78:836-847. [DOI: 10.1002/mrm.26502] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/11/2016] [Accepted: 09/18/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Hyeong Hun Lee
- Department of Biomedical Sciences; Seoul National University; Seoul Korea
| | - Hyeonjin Kim
- Department of Biomedical Sciences; Seoul National University; Seoul Korea
- Department of Radiology; Seoul National University Hospital; Seoul Korea
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology; Seoul National University; Suwon Korea
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35
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Laleg-Kirati TM, Zhang J, Achten E, Serrai H. Spectral data de-noising using semi-classical signal analysis: application to localized MRS. NMR IN BIOMEDICINE 2016; 29:1477-1485. [PMID: 27593698 DOI: 10.1002/nbm.3590] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/28/2016] [Accepted: 07/01/2016] [Indexed: 06/06/2023]
Abstract
In this paper, we propose a new post-processing technique called semi-classical signal analysis (SCSA) for MRS data de-noising. Similar to Fourier transformation, SCSA decomposes the input real positive MR spectrum into a set of linear combinations of squared eigenfunctions equivalently represented by localized functions with shape derived from the potential function of the Schrödinger operator. In this manner, the MRS spectral peaks represented as a sum of these 'shaped like' functions are efficiently separated from noise and accurately analyzed. The performance of the method is tested by analyzing simulated and real MRS data. The results obtained demonstrate that the SCSA method is highly efficient in localized MRS data de-noising and allows for an accurate data quantification.
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Affiliation(s)
- Taous-Meriem Laleg-Kirati
- King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Inria Centre de recherche Bordeaux Sud-Ouest, Talence, France
| | - Jiayu Zhang
- King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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36
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Fadaie F, Mobarakeh NM, Fesharaki SSH, Harirchian MH, Kharazi HH, Rad HS, Habibabadi JM. 1H-MRS metabolite's ratios show temporal alternation in temporal lobe seizure: Comparison between interictal and postictal phases. Epilepsy Res 2016; 128:158-162. [PMID: 27838503 DOI: 10.1016/j.eplepsyres.2016.08.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 07/20/2016] [Accepted: 08/14/2016] [Indexed: 10/21/2022]
Abstract
PURPOSES To determine 1H-MRSI metabolites changes in interictal and postictal phases of patients suffering from mesial temporal lobe epilepsy with hippocampal sclerosis and lateralization of seizure foci. MATERIALS AND METHODS MR spectroscopic imaging was performed in 5 adult patients with refractory temporal lobe epilepsy interictally and immediately after the seizure and in 4 adult control subjects. All patients underwent MR imaging and VideoEEG Monitoring. RESULTS The results showed statistically significant decreases in N-acetylaspartate/Creatine, N-acetylaspartate/Choline and N-acetylaspartate/(creatine+choline) immediately after ictus in ipsilateral hippocampus as compared with control data and contralateral hippocampus of patients while no statistically significant difference was presented in interictal phase. CONCLUSION The present study clearly indicates 1H-MRS abnormalities following an ictus of temporal lobe epilepsy with metabolite recovery in interictal phase. This finding suggests postictal 1H-MRS as a possible useful tool to assist in lateralizing and localizing of seizure foci in epileptic patients with structural lesions.
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Affiliation(s)
- Fatemeh Fadaie
- Comprehensive Epilepsy Program, Epilepsy Monitoring Unit, Pars Hospital, Tehran, Iran
| | - Neda Mohammadi Mobarakeh
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran, Iran; Department of Biomedical Engineering and Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Mohammad Hossein Harirchian
- Department of Neurology, School of Medicine, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Hamidreza Saligheh Rad
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran, Iran; Department of Biomedical Engineering and Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
| | - Jafar Mehvari Habibabadi
- Isfahan Neurosciences Research Center, Neurology Department, Isfahan University of Medical Sciences, Isfahan, Iran.
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Kyathanahally SP, Kreis R. Forecasting the quality of water-suppressed 1 H MR spectra based on a single-shot water scan. Magn Reson Med 2016; 78:441-451. [PMID: 27604395 DOI: 10.1002/mrm.26389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/08/2016] [Accepted: 07/27/2016] [Indexed: 11/07/2022]
Abstract
PURPOSE To investigate whether an initial non-water-suppressed acquisition that provides information about the signal-to-noise ratio (SNR) and linewidth is enough to forecast the maximally achievable final spectral quality and thus inform the operator whether the foreseen number of averages and achieved field homogeneity is adequate. METHODS A large range of spectra with varying SNR and linewidth was simulated and fitted with popular fitting programs to determine the dependence of fitting errors on linewidth and SNR. A tool to forecast variance based on a single acquisition was developed and its performance evaluated on simulated and in vivo data obtained at 3 Tesla from various brain regions and acquisition settings. RESULTS A strong correlation to real uncertainties in estimated metabolite contents was found for the forecast values and the Cramer-Rao lower bounds obtained from the water-suppressed spectra. CONCLUSION It appears to be possible to forecast the best-case errors associated with specific metabolites to be found in model fits of water-suppressed spectra based on a single water scan. Thus, nonspecialist operators will be able to judge ahead of time whether the planned acquisition can possibly be of sufficient quality to answer the targeted clinical question or whether it needs more averages or improved shimming. Magn Reson Med 78:441-451, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sreenath P Kyathanahally
- Department of Clinical Research and Institute of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Roland Kreis
- Department of Clinical Research and Institute of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Bern, Switzerland
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38
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Scavuzzo CJ, Moulton CJ, Larsen RJ. The use of magnetic resonance spectroscopy for assessing the effect of diet on cognition. Nutr Neurosci 2016; 21:1-15. [DOI: 10.1080/1028415x.2016.1218191] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Claire J. Scavuzzo
- Neuroscience Program, University of Illinois at Urbana-Champaign, USA
- Department of Psychology, University of Alberta, Edmonton, Canada
| | | | - Ryan J. Larsen
- Biomedical Imaging Center, Beckman Institute, University of Illinois at Urbana-Champaign, USA
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39
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Key concepts in MR spectroscopy and practical approaches to gaining biochemical information in children. Pediatr Radiol 2016; 46:941-51. [PMID: 27233787 DOI: 10.1007/s00247-014-3204-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 09/11/2014] [Accepted: 10/01/2014] [Indexed: 10/21/2022]
Abstract
Magnetic resonance spectroscopy (MRS) provides independent biochemical information and has become an invaluable adjunct to MRI and other imaging modalities. This review introduces key concepts and presents basic methodological steps regarding the acquisition and the interpretation of proton MRS. We review major brain metabolites and discuss MRS dependence on age, location, echo time and field strength.
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40
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Cuellar-Baena S, Landeck N, Sonnay S, Buck K, Mlynarik V, In 't Zandt R, Kirik D. Assessment of brain metabolite correlates of adeno-associated virus-mediated over-expression of human alpha-synuclein in cortical neurons by in vivo (1) H-MR spectroscopy at 9.4 T. J Neurochem 2016; 137:806-19. [PMID: 26811128 DOI: 10.1111/jnc.13547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 12/19/2022]
Abstract
In this study, we used proton-localized spectroscopy ((1) H-MRS) for the acquisition of the neurochemical profile longitudinally in a novel rat model of human wild-type alpha-synuclein (α-syn) over-expression. Our goal was to find out if the increased α-syn load in this model could be linked to changes in metabolites in the frontal cortex. Animals injected with AAV vectors encoding for human α-syn formed the experimental group, whereas green fluorescent protein expressing animals were used as the vector-treated control group and a third group of uninjected animals were used as naïve controls. Data were acquired at 2, 4, and 8 month time points. Nineteen metabolites were quantified in the MR spectra using LCModel software. On the basis of 92 spectra, we evaluated any potential gender effect and found that lactate (Lac) levels were lower in males compared to females, while the opposite was observed for ascorbate (Asc). Next, we assessed the effect of age and found increased levels of GABA, Tau, and GPC+PCho. Finally, we analyzed the effect of treatment and found that Lac levels (p = 0.005) were specifically lower in the α-syn group compared to the green fluorescent protein and control groups. In addition, Asc levels (p = 0.05) were increased in the vector-injected groups, whereas glucose levels remained unchanged. This study indicates that the metabolic switch between glucose-lactate could be detectable in vivo and might be modulated by Asc. No concomitant changes were found in markers of neuronal integrity (e.g., N-acetylaspartate) consistent with the fact that α-syn over-expression in cortical neurons did not result in neurodegeneration in this model. We acquired the neurochemical profile longitudinally in a rat model of human wild-type alpha-synuclein (α-syn) over-expression in cortical neurons. We found that Lactate levels were reduced in the α-syn group compared to the control groups and Ascorbate levels were increased in the vector-injected groups. No changes were found in markers of neuronal integrity consistent with the fact that α-syn over-expression did not result in frank neurodegeneration.
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Affiliation(s)
- Sandra Cuellar-Baena
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Natalie Landeck
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Sarah Sonnay
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden.,Laboratory of functional and metabolic imaging (LIFMET), École Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
| | - Kerstin Buck
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Vladimir Mlynarik
- Laboratory of functional and metabolic imaging (LIFMET), École Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland.,Department of Radiology and Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - René In 't Zandt
- Lund University BioImaging Center, Lund University, Lund, Sweden
| | - Deniz Kirik
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S), Department of Experimental Medical Science, Lund University, Lund, Sweden.,Lund University BioImaging Center, Lund University, Lund, Sweden
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Vafaeyan H, Ebrahimzadeh SA, Rahimian N, Alavijeh SK, Madadi A, Faeghi F, Harirchian MH, Rad HS. Quantification of diagnostic biomarkers to detect multiple sclerosis lesions employing (1)H-MRSI at 3T. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015; 38:611-8. [PMID: 26526449 DOI: 10.1007/s13246-015-0390-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/19/2015] [Indexed: 11/25/2022]
Abstract
Proton magnetic resonance spectroscopic imaging ((1)H-MRSI) enables the quantification of metabolite concentration ratios in the brain. The major purpose of the current work is to characterize NAA/Cho, NAA/Cr and Myo/Cr in multiple sclerosis (MS) patients, and to estimate their reproducibility in healthy controls. Twelve MS patients and five healthy volunteers were imaged using (1)H-MRSI at 3T. Eddy current correction was performed using a single-voxel non-water suppressed acquisition on an external water phantom. Time-domain quantification was carried out using subtract-QUEST technique, and based on an optimal simulated metabolite database. Reproducibility was evaluated on the same quantified ratios in five normal subjects. An optimal database was created for the quantification of the MRSI data, consisting of choline (Cho), creatine (Cr), N-acetyl aspartate (NAA), lactate (Lac), lipids, myo-inositol (Myo) and glutamine + glutamate (Glx). Decreasing of NAA/Cr and NAA/Cho ratios, as well as an increase in Myo/Cr ratio were observed for MS patients in comparison with control group. Reproducibility of NAA/Cr, NAA/Cho and Myo/Cr in control group was 0.98, 0.87 and 0.64, respectively, expressed as the squared correlation coefficient R (2) between duplicate experiments. We showed that MRSI alongside the time-domain quantification of spectral ratios offers a sensitive and reproducible framework to differentiate MS patients from normals.
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Affiliation(s)
- H Vafaeyan
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (TUMS), Tehran, Iran
- School of Para-Medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - S A Ebrahimzadeh
- Department of Radiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - N Rahimian
- Iranian Center of Neurological Research, TUMS, Tehran, Iran
| | - S Karimi Alavijeh
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (TUMS), Tehran, Iran
- Medical Physics and Biomedical Engineering Department, TUMS, Keshavarz Boulevard, Tehran, Iran
| | - A Madadi
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - F Faeghi
- School of Para-Medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - M H Harirchian
- Iranian Center of Neurological Research, TUMS, Tehran, Iran
| | - H Saligheh Rad
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences (TUMS), Tehran, Iran.
- Medical Physics and Biomedical Engineering Department, TUMS, Keshavarz Boulevard, Tehran, Iran.
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Martel D, Tse Ve Koon K, Le Fur Y, Ratiney H. Localized 2D COSY sequences: Method and experimental evaluation for a whole metabolite quantification approach. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:98-108. [PMID: 26432399 DOI: 10.1016/j.jmr.2015.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 09/03/2015] [Accepted: 09/04/2015] [Indexed: 05/08/2023]
Abstract
Two-dimensional spectroscopy offers the possibility to unambiguously distinguish metabolites by spreading out the multiplet structure of J-coupled spin systems into a second dimension. Quantification methods that perform parametric fitting of the 2D MRS signal have recently been proposed for resolved PRESS (JPRESS) but not explicitly for Localized Correlation Spectroscopy (LCOSY). Here, through a whole metabolite quantification approach, correlation spectroscopy quantification performances are studied. The ability to quantify metabolite relaxation constant times is studied for three localized 2D MRS sequences (LCOSY, LCTCOSY and the JPRESS) in vitro on preclinical MR systems. The issues encountered during implementation and quantification strategies are discussed with the help of the Fisher matrix formalism. The described parameterized models enable the computation of the lower bound for error variance--generally known as the Cramér Rao bounds (CRBs), a standard of precision--on the parameters estimated from these 2D MRS signal fittings. LCOSY has a theoretical net signal loss of two per unit of acquisition time compared to JPRESS. A rapid analysis could point that the relative CRBs of LCOSY compared to JPRESS (expressed as a percentage of the concentration values) should be doubled but we show that this is not necessarily true. Finally, the LCOSY quantification procedure has been applied on data acquired in vivo on a mouse brain.
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Affiliation(s)
- Dimitri Martel
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Claude Bernard Lyon 1, France
| | - K Tse Ve Koon
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Claude Bernard Lyon 1, France
| | - Yann Le Fur
- Aix-Marseille Université, CRMBM, CNRS UMR, 7339 Marseille, France
| | - Hélène Ratiney
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Claude Bernard Lyon 1, France.
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Abstract
INTRODUCTION (1)H-MRS signals from brain tissues capture information on in vivo brain metabolism and neuronal biomarkers. This study aims to advance the use of independent component analysis (ICA) for spectroscopy data by objectively comparing the performance of ICA and LCModel in analyzing realistic data that mimics many of the known properties of in vivo data. METHODS This work identifies key features of in vivo (1)H-MRS signals and presents methods to simulate realistic data, using a basis set of 12 metabolites typically found in the human brain. The realistic simulations provide a much needed ground truth to evaluate performances of various MRS analysis methods. ICA is applied to collectively analyze multiple realistic spectra and independent components identified with our generative model to obtain ICA estimates. These same data are also analyzed using LCModel and the comparisons between the ground-truth and the analysis estimates are presented. The study also investigates the potential impact of modeling inaccuracies by incorporating two sets of model resonances in simulations. RESULTS The simulated fid signals incorporating line broadening, noise, and residual water signal closely resemble the in vivo signals. Simulation analyses show that the resolution performances of both LCModel and ICA are not consistent across metabolites and that while ICA resolution can be improved for certain resonances, ICA is as effective as, or better than, LCModel in resolving most model resonances. CONCLUSION The results show that ICA can be an effective tool in comparing multiple spectra and complements existing approaches for providing quantified estimates.
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Affiliation(s)
- Ravi Kalyanam
- The Mind Research Network Albuquerque, New Mexico ; Department of ECE, University of New Mexico Albuquerque, New Mexico
| | - David Boutte
- The Mind Research Network Albuquerque, New Mexico ; Department of Psychology and Neuroscience, University of Colorado Boulder, Colorado
| | - Kent E Hutchison
- The Mind Research Network Albuquerque, New Mexico ; Department of Psychology and Neuroscience, University of Colorado Boulder, Colorado
| | - Vince D Calhoun
- The Mind Research Network Albuquerque, New Mexico ; Department of ECE, University of New Mexico Albuquerque, New Mexico
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van Ewijk PA, Schrauwen-Hinderling VB, Bekkers SCAM, Glatz JFC, Wildberger JE, Kooi ME. MRS: a noninvasive window into cardiac metabolism. NMR IN BIOMEDICINE 2015; 28:747-66. [PMID: 26010681 DOI: 10.1002/nbm.3320] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 04/02/2015] [Accepted: 04/07/2015] [Indexed: 05/21/2023]
Abstract
A well-functioning heart requires a constant supply of a balanced mixture of nutrients to be used for the production of adequate amounts of adenosine triphosphate, which is the main energy source for most cellular functions. Defects in cardiac energy metabolism are linked to several myocardial disorders. MRS can be used to study in vivo changes in cardiac metabolism noninvasively. MR techniques allow repeated measurements, so that disease progression and the response to treatment or to a lifestyle intervention can be monitored. It has also been shown that MRS can predict clinical heart failure and death. This article focuses on in vivo MRS to assess cardiac metabolism in humans and experimental animals, as experimental animals are often used to investigate the mechanisms underlying the development of metabolic diseases. Various MR techniques, such as cardiac (31) P-MRS, (1) H-MRS, hyperpolarized (13) C-MRS and Dixon MRI, are described. A short overview of current and emerging applications is given. Cardiac MRS is a promising technique for the investigation of the relationship between cardiac metabolism and cardiac disease. However, further optimization of scan time and signal-to-noise ratio is required before broad clinical application. In this respect, the ongoing development of advanced shimming algorithms, radiofrequency pulses, pulse sequences, (multichannel) detection coils, the use of hyperpolarized nuclei and scanning at higher magnetic field strengths offer future perspective for clinical applications of MRS.
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Affiliation(s)
- Petronella A van Ewijk
- Maastricht University Medical Center, Human Biology, Maastricht, the Netherlands
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
| | - Vera B Schrauwen-Hinderling
- Maastricht University Medical Center, Human Biology, Maastricht, the Netherlands
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
| | | | - Jan F C Glatz
- Maastricht University Medical Center, Molecular Genetics, Maastricht, the Netherlands
- Maastricht University Medical Center, CARIM - Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
| | | | - M Eline Kooi
- Maastricht University Medical Center, Radiology, Maastricht, the Netherlands
- Maastricht University Medical Center, NUTRIM - School for Nutrition, Toxicology and Metabolism, Maastricht, the Netherlands
- Maastricht University Medical Center, CARIM - Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands
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Rabinovitch A, Biton Y, Braunstein D, Friedman M, Aviram I, Yandrapalli S, Pandit SV, Berenfeld O. Singular Value Decomposition of Optically-Mapped Cardiac Rotors and Fibrillatory Activity. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2015; 48:095401. [PMID: 26668401 PMCID: PMC4676718 DOI: 10.1088/0022-3727/48/9/095401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Our progress of understanding how cellular and structural factors contribute to the arrhythmia is hampered in part because of controversies whether a fibrillating heart is driven by a single, several, or multiple number of sources, and whether they are focal or reentrant, and how to localize them. Here we demonstrate how a novel usage of the neutral singular value decomposition (SVD) method enables the extraction of the governing spatial and temporal modes of excitation from a rotor and fibrillatory waves. Those modes highlight patterns and regions of organization in the midst of the otherwise seemingly-randomly propagating excitation waves. We apply the method to experimental models of cardiac fibrillation in rabbit hearts. We show that the SVD analysis is able to enhance the classification of the heart electrical patterns into regions harboring drivers in the form of fast reentrant activity and other regions of by-standing activity. This enhancement is accomplished without any prior assumptions regarding the spatial, temporal or spectral properties of those drivers. The analysis corroborates that the dominant mode has the highest activation rate and further reveals a new feature: A transfer of modes from the driving to the passive regions resulting in a partial reaction of the passive region to the driving region.
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Affiliation(s)
- A. Rabinovitch
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Y. Biton
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - D. Braunstein
- Physics Department. Sami Shamoon College of Engineering, Beer-Sheva, Israel
| | - M. Friedman
- Department of Information Systems Engineering, Ben-Gurion University, Beer Sheva 84105, Israel
| | - I. Aviram
- Physics Department, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - S. Yandrapalli
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, USA
| | - S. V. Pandit
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, USA
| | - O. Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, USA
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Wiśniewski M, Zieliński TP. Joint application of audio spectral envelope and tonality index in an e-asthma monitoring system. IEEE J Biomed Health Inform 2014; 19:1009-18. [PMID: 25167561 DOI: 10.1109/jbhi.2014.2352302] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper presents in detail a recently introduced highly efficient method for automatic detection of asthmatic wheezing in breathing sounds. The fluctuation in the audio spectral envelope (ASE) from the MPEG-7 standard and the value of the tonality index (TI) from the MPEG-2 Audio specification are jointly used as discriminative features for wheezy sounds, while the support vector machine (SVM) with a polynomial kernel serves as a classifier. The advantages of the proposed approach are described in the paper (e.g., detecting weak wheezes, very good ROC characteristics, independence from noise color). Since the method is not computationally complex, it is suitable for remote asthma monitoring using mobile devices (personal medical assistants). The main contribution of this paper consists of presenting all the implementation details concerning the proposed approach for the first time, i.e., the pseudocode of the method and adjusting the values of the ASE and TI parameters after which only one (not two) FFT is required for analysis of a next overlapping signal fragment. The efficiency of the method has also been additionally confirmed by the AdaBoost classifier with a built-in mechanism to feature ranking, as well as a previously performed minimal-redundancy-maximal-relevance test.
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48
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Passeri A, Mazzuca S, Bene VD. Radiofrequency field inhomogeneity compensation in high spatial resolution magnetic resonance spectroscopic imaging. Phys Med Biol 2014; 59:2913-34. [PMID: 24828836 DOI: 10.1088/0031-9155/59/12/2913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Clinical magnetic resonance spectroscopy imaging (MRSI) is a non-invasive functional technique, whose mathematical framework falls into the category of linear inverse problems. However, its use in medical diagnostics is hampered by two main problems, both linked to the Fourier-based technique usually implemented for spectra reconstruction: poor spatial resolution and severe blurring in the spatial localization of the reconstructed spectra. Moreover, the intrinsic ill-posedness of the MRSI problem might be worsened by (i) spatially dependent distortions of the static magnetic field (B0) distribution, as well as by (ii) inhomogeneity in the power deposition distribution of the radiofrequency magnetic field (B1). Among several alternative methods, slim (Spectral Localization by IMaging) and bslim (B0 compensated slim) are reconstruction algorithms in which a priori information concerning the spectroscopic target is introduced into the reconstruction kernel. Nonetheless, the influence of the B1 field, particularly when its operating wavelength is close to the size of the human organs being studied, continues to be disregarded. starslim (STAtic and Radiofrequency-compensated slim), an evolution of the slim and bslim methods, is therefore proposed, in which the transformation kernel also includes the B1 field inhomogeneity map, thus allowing almost complete 3D modelling of the MRSI problem. Moreover, an original method for the experimental determination of the B1 field inhomogeneity map specific to the target under evaluation is also included. The compensation capabilities of the proposed method have been tested and illustrated using synthetic raw data reproducing the human brain.
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Mosconi E, Sima DM, Osorio Garcia MI, Fontanella M, Fiorini S, Van Huffel S, Marzola P. Different quantification algorithms may lead to different results: a comparison using proton MRS lipid signals. NMR IN BIOMEDICINE 2014; 27:431-43. [PMID: 24493129 DOI: 10.1002/nbm.3079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 01/01/2014] [Accepted: 01/02/2014] [Indexed: 05/24/2023]
Abstract
Proton magnetic resonance spectroscopy (MRS) is a sensitive method for investigating the biochemical compounds in a tissue. The interpretation of the data relies on the quantification algorithms applied to MR spectra. Each of these algorithms has certain underlying assumptions and may allow one to incorporate prior knowledge, which could influence the quality of the fit. The most commonly considered types of prior knowledge include the line-shape model (Lorentzian, Gaussian, Voigt), knowledge of the resonating frequencies, modeling of the baseline, constraints on the damping factors and phase, etc. In this article, we study whether the statistical outcome of a biological investigation can be influenced by the quantification method used. We chose to study lipid signals because of their emerging role in the investigation of metabolic disorders. Lipid spectra, in particular, are characterized by peaks that are in most cases not Lorentzian, because measurements are often performed in difficult body locations, e.g. in visceral fats close to peristaltic movements in humans or very small areas close to different tissues in animals. This leads to spectra with several peak distortions. Linear combination of Model spectra (LCModel), Advanced Method for Accurate Robust and Efficient Spectral fitting (AMARES), quantitation based on QUantum ESTimation (QUEST), Automated Quantification of Short Echo-time MRS (AQSES)-Lineshape and Integration were applied to simulated spectra, and area under the curve (AUC) values, which are proportional to the quantity of the resonating molecules in the tissue, were compared with true values. A comparison between techniques was also carried out on lipid signals from obese and lean Zucker rats, for which the polyunsaturation value expressed in white adipose tissue should be statistically different, as confirmed by high-resolution NMR measurements (considered the gold standard) on the same animals. LCModel, AQSES-Lineshape, QUEST and Integration gave the best results in at least one of the considered groups of simulated or in vivo lipid signals. These outcomes highlight the fact that quantification methods can influence the final result and its statistical significance.
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Affiliation(s)
- E Mosconi
- Department of Computer Science, University of Verona, Verona, Italy
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Mitchell J, Gladden LF, Chandrasekera TC, Fordham EJ. Low-field permanent magnets for industrial process and quality control. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 76:1-60. [PMID: 24360243 DOI: 10.1016/j.pnmrs.2013.09.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 05/13/2023]
Abstract
In this review we focus on the technology associated with low-field NMR. We present the current state-of-the-art in low-field NMR hardware and experiments, considering general magnet designs, rf performance, data processing and interpretation. We provide guidance on obtaining the optimum results from these instruments, along with an introduction for those new to low-field NMR. The applications of lowfield NMR are now many and diverse. Furthermore, niche applications have spawned unique magnet designs to accommodate the extremes of operating environment or sample geometry. Trying to capture all the applications, methods, and hardware encompassed by low-field NMR would be a daunting task and likely of little interest to researchers or industrialists working in specific subject areas. Instead we discuss only a few applications to highlight uses of the hardware and experiments in an industrial environment. For details on more particular methods and applications, we provide citations to specialized review articles.
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Affiliation(s)
- J Mitchell
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom; Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
| | - L F Gladden
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom.
| | - T C Chandrasekera
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
| | - E J Fordham
- Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
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