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Rakić M, Turco F, Weng G, Maes F, Sima DM, Slotboom J. Deep learning pipeline for quality filtering of MRSI spectra. NMR IN BIOMEDICINE 2024; 37:e5012. [PMID: 37518942 DOI: 10.1002/nbm.5012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/15/2023] [Accepted: 07/10/2023] [Indexed: 08/01/2023]
Abstract
With the rise of novel 3D magnetic resonance spectroscopy imaging (MRSI) acquisition protocols in clinical practice, which are capable of capturing a large number of spectra from a subject's brain, there is a need for an automated preprocessing pipeline that filters out bad-quality spectra and identifies contaminated but salvageable spectra prior to the metabolite quantification step. This work introduces such a pipeline based on an ensemble of deep-learning classifiers. The dataset consists of 36,338 spectra from one healthy subject and five brain tumor patients, acquired with an EPSI variant, which implemented a novel type of spectral editing named SLOtboom-Weng (SLOW) editing on a 7T MR scanner. The spectra were labeled manually by an expert into four classes of spectral quality as follows: (i) noise, (ii) spectra greatly influenced by lipid-related artifacts (deemed not to contain clinical information), (iii) spectra containing metabolic information slightly contaminated by lipid signals, and (iv) good-quality spectra. The AI model consists of three pairs of networks, each comprising a convolutional autoencoder and a multilayer perceptron network. In the classification step, the encoding half of the autoencoder is kept as a dimensionality reduction tool, while the fully connected layers are added to its output. Each of the three pairs of networks is trained on different representations of spectra (real, imaginary, or both), aiming at robust decision-making. The final class is assigned via a majority voting scheme. The F1 scores obtained on the test dataset for the four previously defined classes are 0.96, 0.93, 0.82, and 0.90, respectively. The arguably lower value of 0.82 was reached for the least represented class of spectra mildly influenced by lipids. Not only does the proposed model minimise the required user interaction, but it also greatly reduces the computation time at the metabolite quantification step (by selecting a subset of spectra worth quantifying) and enforces the display of only clinically relevant information.
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Affiliation(s)
- Mladen Rakić
- Research and Development, Icometrix, Leuven, Belgium
- Department of Electrical Engineering (ESAT), Processing Speech and Images (PSI) and Medical Imaging Research Center, KU Leuven, Leuven, Belgium
| | - Federico Turco
- Institute for Diagnostic and Interventional Radiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Bern, Switzerland
| | - Guodong Weng
- Institute for Diagnostic and Interventional Radiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Bern, Switzerland
| | - Frederik Maes
- Department of Electrical Engineering (ESAT), Processing Speech and Images (PSI) and Medical Imaging Research Center, KU Leuven, Leuven, Belgium
| | - Diana M Sima
- Research and Development, Icometrix, Leuven, Belgium
| | - Johannes Slotboom
- Institute for Diagnostic and Interventional Radiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Bern, Switzerland
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2
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Zhao T, Grist JT, Auer DP, Avula S, Bailey S, Davies NP, Grundy RG, Khan O, MacPherson L, Morgan PS, Pizer B, Rose HEL, Sun Y, Wilson M, Worthington L, Arvanitis TN, Peet AC. Noise suppression of proton magnetic resonance spectroscopy improves paediatric brain tumour classification. NMR IN BIOMEDICINE 2024; 37:e5129. [PMID: 38494431 DOI: 10.1002/nbm.5129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 01/07/2024] [Accepted: 02/03/2024] [Indexed: 03/19/2024]
Abstract
Proton magnetic resonance spectroscopy (1H-MRS) is increasingly used for clinical brain tumour diagnosis, but suffers from limited spectral quality. This retrospective and comparative study aims at improving paediatric brain tumour classification by performing noise suppression on clinical 1H-MRS. Eighty-three/forty-two children with either an ependymoma (ages 4.6 ± 5.3/9.3 ± 5.4), a medulloblastoma (ages 6.9 ± 3.5/6.5 ± 4.4), or a pilocytic astrocytoma (8.0 ± 3.6/6.3 ± 5.0), recruited from four centres across England, were scanned with 1.5T/3T short-echo-time point-resolved spectroscopy. The acquired raw 1H-MRS was quantified by using Totally Automatic Robust Quantitation in NMR (TARQUIN), assessed by experienced spectroscopists, and processed with adaptive wavelet noise suppression (AWNS). Metabolite concentrations were extracted as features, selected based on multiclass receiver operating characteristics, and finally used for identifying brain tumour types with supervised machine learning. The minority class was oversampled through the synthetic minority oversampling technique for comparison purposes. Post-noise-suppression 1H-MRS showed significantly elevated signal-to-noise ratios (P < .05, Wilcoxon signed-rank test), stable full width at half-maximum (P > .05, Wilcoxon signed-rank test), and significantly higher classification accuracy (P < .05, Wilcoxon signed-rank test). Specifically, the cross-validated overall and balanced classification accuracies can be improved from 81% to 88% overall and 76% to 86% balanced for the 1.5T cohort, whilst for the 3T cohort they can be improved from 62% to 76% overall and 46% to 56%, by applying Naïve Bayes on the oversampled 1H-MRS. The study shows that fitting-based signal-to-noise ratios of clinical 1H-MRS can be significantly improved by using AWNS with insignificantly altered line width, and the post-noise-suppression 1H-MRS may have better diagnostic performance for paediatric brain tumours.
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Affiliation(s)
- Teddy Zhao
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Oncology, Birmingham Children's Hospital, Birmingham, UK
| | - James T Grist
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - Dorothee P Auer
- Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Shivaram Avula
- Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - Simon Bailey
- Paediatric Oncology, Great North Children's Hospital, Newcastle upon Tyne, UK
| | - Nigel P Davies
- Imaging and Medical Physics, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | - Omar Khan
- Digital Healthcare, WMG, University of Warwick, Coventry, UK
| | | | - Paul S Morgan
- Clinical Neuroscience, University of Nottingham, Nottingham, UK
- Children's Brain Tumour Research Centre, University of Nottingham, Nottingham, UK
- Medical Physics, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | | | - Heather E L Rose
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Oncology, Birmingham Children's Hospital, Birmingham, UK
| | - Yu Sun
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Oncology, Birmingham Children's Hospital, Birmingham, UK
| | - Martin Wilson
- Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Lara Worthington
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Oncology, Birmingham Children's Hospital, Birmingham, UK
- RRPPS, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Theodoros N Arvanitis
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Oncology, Birmingham Children's Hospital, Birmingham, UK
- Digital Healthcare, WMG, University of Warwick, Coventry, UK
- Engineering, University of Birmingham, Birmingham, UK
| | - Andrew C Peet
- Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Oncology, Birmingham Children's Hospital, Birmingham, UK
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3
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Buitinga M, Veeraiah P, Haans F, Schrauwen-Hinderling VB. Ectopic lipid deposition in muscle and liver, quantified by proton magnetic resonance spectroscopy. Obesity (Silver Spring) 2023; 31:2447-2459. [PMID: 37667838 DOI: 10.1002/oby.23865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/09/2023] [Accepted: 05/09/2023] [Indexed: 09/06/2023]
Abstract
Advances in the development of noninvasive imaging techniques have spurred investigations into ectopic lipid deposition in the liver and muscle and its implications in the development of metabolic diseases such as type 2 diabetes. Computed tomography and ultrasound have been applied in the past, though magnetic resonance-based methods are currently considered the gold standard as they allow more accurate quantitative detection of ectopic lipid stores. This review focuses on methodological considerations of magnetic resonance-based methods to image hepatic and muscle fat fractions, and it emphasizes anatomical and morphological aspects and how these may influence data acquisition, analysis, and interpretation.
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Affiliation(s)
- Mijke Buitinga
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Nutrition and Movement Sciences (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Pandichelvam Veeraiah
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
- Scannexus (Ultra-High Field Imaging Center), Maastricht, The Netherlands
- Faculty of Health Medicine and Life Sciences (FHML), Maastricht, The Netherlands
| | - Florian Haans
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Vera B Schrauwen-Hinderling
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Nutrition and Movement Sciences (NUTRIM), Maastricht University, Maastricht, The Netherlands
- Institute for Clinical Diabetology, German Diabetes Center and Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
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4
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Tsampasian V, Cameron D, Sobhan R, Bazoukis G, Vassiliou VS. Phosphorus Magnetic Resonance Spectroscopy ( 31P MRS) and Cardiovascular Disease: The Importance of Energy. Medicina (B Aires) 2023; 59:medicina59010174. [PMID: 36676798 PMCID: PMC9866867 DOI: 10.3390/medicina59010174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 01/17/2023] Open
Abstract
Background and Objectives: The heart is the organ with the highest metabolic demand in the body, and it relies on high ATP turnover and efficient energy substrate utilisation in order to function normally. The derangement of myocardial energetics may lead to abnormalities in cardiac metabolism, which herald the symptoms of heart failure (HF). In addition, phosphorus magnetic resonance spectroscopy (31P MRS) is the only available non-invasive method that allows clinicians and researchers to evaluate the myocardial metabolic state in vivo. This review summarises the importance of myocardial energetics and provides a systematic review of all the available research studies utilising 31P MRS to evaluate patients with a range of cardiac pathologies. Materials and Methods: We have performed a systematic review of all available studies that used 31P MRS for the investigation of myocardial energetics in cardiovascular disease. Results: A systematic search of the Medline database, the Cochrane library, and Web of Science yielded 1092 results, out of which 62 studies were included in the systematic review. The 31P MRS has been used in numerous studies and has demonstrated that impaired myocardial energetics is often the beginning of pathological processes in several cardiac pathologies. Conclusions: The 31P MRS has become a valuable tool in the understanding of myocardial metabolic changes and their impact on the diagnosis, risk stratification, and prognosis of patients with cardiovascular diseases.
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Affiliation(s)
- Vasiliki Tsampasian
- Norwich Medical School, University of East Anglia, Bob Champion Research & Education Building, Research Park, Rosalind Franklin Rd, Norwich NR4 7UQ, UK
- Correspondence: (V.T.); (V.S.V.)
| | - Donnie Cameron
- C.J. Gorter MRI Center, Department of Radiology, Leiden University Medical Centre, 2333 ZA Leiden, The Netherlands
| | - Rashed Sobhan
- Norwich Medical School, University of East Anglia, Bob Champion Research & Education Building, Research Park, Rosalind Franklin Rd, Norwich NR4 7UQ, UK
| | - George Bazoukis
- Department of Cardiology, Larnaca General Hospital, Larnaca 6301, Cyprus
- Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia 2417, Cyprus
| | - Vassilios S. Vassiliou
- Norwich Medical School, University of East Anglia, Bob Champion Research & Education Building, Research Park, Rosalind Franklin Rd, Norwich NR4 7UQ, UK
- Correspondence: (V.T.); (V.S.V.)
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In Vivo Magnetic Resonance Spectroscopy Methods for Investigating Cardiac Metabolism. Metabolites 2022; 12:metabo12020189. [PMID: 35208262 PMCID: PMC8877606 DOI: 10.3390/metabo12020189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 11/17/2022] Open
Abstract
Magnetic resonance spectroscopy (MRS) is a non-invasive and non-ionizing technique, enabling in vivo investigation of cardiac metabolism in normal and diseased hearts. In vivo measurement tools are critical for studying mechanisms that regulate cardiac energy metabolism in disease developments and to assist in early response assessments to novel therapies. For cardiac MRS, proton (1H), phosphorus (31P), and hyperpolarized 13-carbon (13C) provide valuable metabolic information for diagnosis and treatment assessment purposes. Currently, low sensitivity and some technical limitations limit the utility of MRS. An essential step in translating MRS for clinical use involves further technological improvements, particularly in coil design, improving the signal-to-noise ratios, field homogeneity, and optimizing radiofrequency sequences. This review addresses the recent advances in metabolic imaging by MRS from primarily the literature published since 2015.
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Zabow G, Dodd S, Koretsky A. The misunderstood meander: Redesigning MRI meander-line surface coils to reduce noise, increase uniformity, and eliminate image artifacts. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 333:107100. [PMID: 34801823 PMCID: PMC9262143 DOI: 10.1016/j.jmr.2021.107100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/05/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Meander-line, or zig-zag, MRI surface coils theoretically promise spatially uniform fields with optimal field localization close to the coil. In reality, they suffer poorer than expected field localizations and acquired images are often highly inhomogeneous, plagued by repeating stripe-like signal-loss artifacts. We show that both these detrimental effects arise from coil design based on the same invalid approximation in the underlying theory. Here, the conventional approximation is corrected, yielding a modified coil design that validates the new theory by rectifying the above problems. Specifically, an easily implementable coil correction, which amounts to the addition of a single extra turn of wire, is introduced and shown to increase signal uniformity by an order of magnitude, eliminate image artifacts, and reduce unwanted signal interference from deeper within the sample by tightening the coil field localization to close to the coil, as intended for zig-zag designs. With independent optimization of coil size and imaging depth possible, such corrected meander-lines surface coils may be well suited for large area, near-surface imaging and spectroscopy applications.
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Affiliation(s)
- Gary Zabow
- Applied Physics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA.
| | - Stephen Dodd
- Laboratory of Functional and Molecular Imaging, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alan Koretsky
- Laboratory of Functional and Molecular Imaging, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
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Krššák M, Lindeboom L, Schrauwen‐Hinderling V, Szczepaniak LS, Derave W, Lundbom J, Befroy D, Schick F, Machann J, Kreis R, Boesch C. Proton magnetic resonance spectroscopy in skeletal muscle: Experts' consensus recommendations. NMR IN BIOMEDICINE 2021; 34:e4266. [PMID: 32022964 PMCID: PMC8244035 DOI: 10.1002/nbm.4266] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/21/2019] [Accepted: 01/15/2020] [Indexed: 05/02/2023]
Abstract
1 H-MR spectroscopy of skeletal muscle provides insight into metabolism that is not available noninvasively by other methods. The recommendations given in this article are intended to guide those who have basic experience in general MRS to the special application of 1 H-MRS in skeletal muscle. The highly organized structure of skeletal muscle leads to effects that change spectral features far beyond simple peak heights, depending on the type and orientation of the muscle. Specific recommendations are given for the acquisition of three particular metabolites (intramyocellular lipids, carnosine and acetylcarnitine) and for preconditioning of experiments and instructions to study volunteers.
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Affiliation(s)
- Martin Krššák
- Division of Endocrinology and Metabolism, Department of Internal Medicine III & High Field MR Centre, Department of Biomedical Imaging and Image guided TherapyMedical University of ViennaViennaAustria
| | - Lucas Lindeboom
- Department of Radiology and Nuclear Medicine and Department of Nutrition and Movement ScienceMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Vera Schrauwen‐Hinderling
- Department of Radiology and Nuclear Medicine and Department of Nutrition and Movement ScienceMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Lidia S. Szczepaniak
- Biomedical Research Consulting in Magnetic Resonance SpectroscopyAlbuquerqueNew Mexico
| | - Wim Derave
- Department of Movement and Sports SciencesGhent UniversityGhentBelgium
| | - Jesper Lundbom
- Department of Diagnostics and TherapeuticsUniversity of HelsinkiHelsinkiFinland
| | | | - Fritz Schick
- Section on Experimental Radiology, Department of Diagnostic and Interventional RadiologyUniversity Hospital TübingenTübingenGermany
| | - Jürgen Machann
- Section on Experimental Radiology, Department of Diagnostic and Interventional RadiologyUniversity Hospital TübingenTübingenGermany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich at the University of TübingenTübingenGermany
- German Center for Diabetes Research (DZD)TübingenGermany
| | - Roland Kreis
- Departments of Radiology and Biomedical ResearchUniversity and InselspitalBernSwitzerland
| | - Chris Boesch
- Departments of Radiology and Biomedical ResearchUniversity and InselspitalBernSwitzerland
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8
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Ruiz-Rodado V, Brender JR, Cherukuri MK, Gilbert MR, Larion M. Magnetic resonance spectroscopy for the study of cns malignancies. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 122:23-41. [PMID: 33632416 PMCID: PMC7910526 DOI: 10.1016/j.pnmrs.2020.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 05/04/2023]
Abstract
Despite intensive research, brain tumors are amongst the malignancies with the worst prognosis; therefore, a prompt diagnosis and thoughtful assessment of the disease is required. The resistance of brain tumors to most forms of conventional therapy has led researchers to explore the underlying biology in search of new vulnerabilities and biomarkers. The unique metabolism of brain tumors represents one potential vulnerability and the basis for a system of classification. Profiling this aberrant metabolism requires a method to accurately measure and report differences in metabolite concentrations. Magnetic resonance-based techniques provide a framework for examining tumor tissue and the evolution of disease. Nuclear Magnetic Resonance (NMR) analysis of biofluids collected from patients suffering from brain cancer can provide biological information about disease status. In particular, urine and plasma can serve to monitor the evolution of disease through the changes observed in the metabolic profiles. Moreover, cerebrospinal fluid can be utilized as a direct reporter of cerebral activity since it carries the chemicals exchanged with the brain tissue and the tumor mass. Metabolic reprogramming has recently been included as one of the hallmarks of cancer. Accordingly, the metabolic rewiring experienced by these tumors to sustain rapid growth and proliferation can also serve as a potential therapeutic target. The combination of 13C tracing approaches with the utilization of different NMR spectral modalities has allowed investigations of the upregulation of glycolysis in the aggressive forms of brain tumors, including glioblastomas, and the discovery of the utilization of acetate as an alternative cellular fuel in brain metastasis and gliomas. One of the major contributions of magnetic resonance to the assessment of brain tumors has been the non-invasive determination of 2-hydroxyglutarate (2HG) in tumors harboring a mutation in isocitrate dehydrogenase 1 (IDH1). The mutational status of this enzyme already serves as a key feature in the clinical classification of brain neoplasia in routine clinical practice and pilot studies have established the use of in vivo magnetic resonance spectroscopy (MRS) for monitoring disease progression and treatment response in IDH mutant gliomas. However, the development of bespoke methods for 2HG detection by MRS has been required, and this has prevented the wider implementation of MRS methodology into the clinic. One of the main challenges for improving the management of the disease is to obtain an accurate insight into the response to treatment, so that the patient can be promptly diverted into a new therapy if resistant or maintained on the original therapy if responsive. The implementation of 13C hyperpolarized magnetic resonance spectroscopic imaging (MRSI) has allowed detection of changes in tumor metabolism associated with a treatment, and as such has been revealed as a remarkable tool for monitoring response to therapeutic strategies. In summary, the application of magnetic resonance-based methodologies to the diagnosis and management of brain tumor patients, in addition to its utilization in the investigation of its tumor-associated metabolic rewiring, is helping to unravel the biological basis of malignancies of the central nervous system.
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Affiliation(s)
- Victor Ruiz-Rodado
- Neuro-Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institute of Health, Bethesda, United States.
| | - Jeffery R Brender
- Radiation Biology Branch, Center for Cancer Research, National Institute of Health, Bethesda, United States
| | - Murali K Cherukuri
- Radiation Biology Branch, Center for Cancer Research, National Institute of Health, Bethesda, United States
| | - Mark R Gilbert
- Neuro-Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institute of Health, Bethesda, United States
| | - Mioara Larion
- Neuro-Oncology Branch, National Cancer Institute, Center for Cancer Research, National Institute of Health, Bethesda, United States.
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9
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Dorst J, Ruhm L, Avdievich N, Bogner W, Henning A. Comparison of four 31P single-voxel MRS sequences in the human brain at 9.4 T. Magn Reson Med 2021; 85:3010-3026. [PMID: 33427322 DOI: 10.1002/mrm.28658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 01/30/2023]
Abstract
PURPOSE In this study, different single-voxel localization sequences were implemented and systematically compared for the first time for phosphorous MRS (31 P-MRS) in the human brain at 9.4 T. METHODS Two multishot sequences, image-selected in vivo spectroscopy (ISIS) and a conventional slice-selective excitation combined with localization by adiabatic selective refocusing (semiLASER) variant of the spin-echo full intensity-acquired localized spectroscopy (SPECIAL-semiLASER), and two single-shot sequences, semiLASER and stimulated echo acquisition mode (STEAM), were implemented and optimized for 31 P-MRS in the human brain at 9.4 T. Pulses and coil setup were optimized, localization accuracy was tested in phantom experiments, and absolute SNR of the sequences was compared in vivo. The SNR per unit time (SNR/t) was derived and compared for all four sequences and verified experimentally for ISIS in two different voxel sizes (3 × 3 × 3 cm3 , 5 × 5 × 5 cm3 , 10-minute measurement time). Metabolite signals obtained with ISIS were quantified. The possible spectral quality in vivo acquired in clinically feasible time (3:30 minutes, 3 × 3 × 3 cm3 ) was explored for two different coil setups. RESULTS All evaluated sequences performed with good localization accuracy in phantom experiments and provided well-resolved spectra in vivo. However, ISIS has the lowest chemical shift displacement error, the best localization accuracy, the highest SNR/t for most metabolites, provides metabolite concentrations comparable to literature values, and is the only one of the sequences that allows for the detection of the whole 31 P spectrum, including β-adenosine triphosphate, with the used setup. The SNR/t of STEAM is comparable to the SNR/t of ISIS. The semiLASER and SPECIAL-semiLASER sequences provide good results for metabolites with long T2 . CONCLUSION At 9.4 T, high-quality single-voxel localized 31 P-MRS can be performed in the human brain with different localization methods, each with inherent characteristics suitable for different research issues.
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Affiliation(s)
- Johanna Dorst
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany
| | - Loreen Ruhm
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany
| | - Nikolai Avdievich
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Wolfgang Bogner
- High-Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Anke Henning
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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10
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Kreis R, Boer V, Choi I, Cudalbu C, de Graaf RA, Gasparovic C, Heerschap A, Krššák M, Lanz B, Maudsley AA, Meyerspeer M, Near J, Öz G, Posse S, Slotboom J, Terpstra M, Tkáč I, Wilson M, Bogner W. Terminology and concepts for the characterization of in vivo MR spectroscopy methods and MR spectra: Background and experts' consensus recommendations. NMR IN BIOMEDICINE 2020; 34:e4347. [PMID: 32808407 PMCID: PMC7887137 DOI: 10.1002/nbm.4347] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 05/04/2023]
Abstract
With a 40-year history of use for in vivo studies, the terminology used to describe the methodology and results of magnetic resonance spectroscopy (MRS) has grown substantially and is not consistent in many aspects. Given the platform offered by this special issue on advanced MRS methodology, the authors decided to describe many of the implicated terms, to pinpoint differences in their meanings and to suggest specific uses or definitions. This work covers terms used to describe all aspects of MRS, starting from the description of the MR signal and its theoretical basis to acquisition methods, processing and to quantification procedures, as well as terms involved in describing results, for example, those used with regard to aspects of quality, reproducibility or indications of error. The descriptions of the meanings of such terms emerge from the descriptions of the basic concepts involved in MRS methods and examinations. This paper also includes specific suggestions for future use of terms where multiple conventions have emerged or coexisted in the past.
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Affiliation(s)
- Roland Kreis
- Department of Radiology, Neuroradiology, and Nuclear Medicine and Department of Biomedical ResearchUniversity BernBernSwitzerland
| | - Vincent Boer
- Danish Research Centre for Magnetic Resonance, Funktions‐ og Billeddiagnostisk EnhedCopenhagen University Hospital HvidovreHvidovreDenmark
| | - In‐Young Choi
- Department of Neurology, Hoglund Brain Imaging CenterUniversity of Kansas Medical CenterKansas CityKansasUSA
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM)Ecole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Robin A. de Graaf
- Department of Radiology and Biomedical Imaging & Department of Biomedical EngineeringYale UniversityNew HavenConnecticutUSA
| | | | - Arend Heerschap
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Martin Krššák
- Division of Endocrinology and Metabolism, Department of Internal Medicine III & High Field MR Centre, Department of Biomedical Imaging and Image guided TherapyMedical University of ViennaViennaAustria
| | - Bernard Lanz
- Laboratory of Functional and Metabolic Imaging (LIFMET)Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
- Sir Peter Mansfield Imaging Centre, School of MedicineUniversity of NottinghamNottinghamUK
| | - Andrew A. Maudsley
- Department of Radiology, Miller School of MedicineUniversity of MiamiMiamiFloridaUSA
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- High Field MR CenterMedical University of ViennaViennaAustria
| | - Jamie Near
- Douglas Mental Health University Institute and Department of PsychiatryMcGill UniversityMontrealCanada
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of RadiologyUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Stefan Posse
- Department of NeurologyUniversity of New Mexico School of MedicineAlbuquerqueNew MexicoUSA
| | - Johannes Slotboom
- Department of Radiology, Neuroradiology, and Nuclear MedicineUniversity Hospital BernBernSwitzerland
| | - Melissa Terpstra
- Center for Magnetic Resonance Research, Department of RadiologyUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Ivan Tkáč
- Center for Magnetic Resonance Research, Department of RadiologyUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Martin Wilson
- Centre for Human Brain Health and School of PsychologyUniversity of BirminghamBirminghamUK
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
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Bakermans AJ, Bazil JN, Nederveen AJ, Strijkers GJ, Boekholdt SM, Beard DA, Jeneson JAL. Human Cardiac 31P-MR Spectroscopy at 3 Tesla Cannot Detect Failing Myocardial Energy Homeostasis during Exercise. Front Physiol 2017; 8:939. [PMID: 29230178 PMCID: PMC5712006 DOI: 10.3389/fphys.2017.00939] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022] Open
Abstract
Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) is a unique non-invasive imaging modality for probing in vivo high-energy phosphate metabolism in the human heart. We investigated whether current 31P-MRS methodology would allow for clinical applications to detect exercise-induced changes in (patho-)physiological myocardial energy metabolism. Hereto, measurement variability and repeatability of three commonly used localized 31P-MRS methods [3D image-selected in vivo spectroscopy (ISIS) and 1D ISIS with 1D chemical shift imaging (CSI) oriented either perpendicular or parallel to the surface coil] to quantify the myocardial phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio in healthy humans (n = 8) at rest were determined on a clinical 3 Tesla MR system. Numerical simulations of myocardial energy homeostasis in response to increased cardiac work rates were performed using a biophysical model of myocardial oxidative metabolism. Hypertrophic cardiomyopathy was modeled by either inefficient sarcomere ATP utilization or decreased mitochondrial ATP synthesis. The effect of creatine depletion on myocardial energy homeostasis was explored for both conditions. The mean in vivo myocardial PCr/ATP ratio measured with 3D ISIS was 1.57 ± 0.17 with a large repeatability coefficient of 40.4%. For 1D CSI in a 1D ISIS-selected slice perpendicular to the surface coil, the PCr/ATP ratio was 2.78 ± 0.50 (repeatability 42.5%). With 1D CSI in a 1D ISIS-selected slice parallel to the surface coil, the PCr/ATP ratio was 1.70 ± 0.56 (repeatability 43.7%). The model predicted a PCr/ATP ratio reduction of only 10% at the maximal cardiac work rate in normal myocardium. Hypertrophic cardiomyopathy led to lower PCr/ATP ratios for high cardiac work rates, which was exacerbated by creatine depletion. Simulations illustrated that when conducting cardiac 31P-MRS exercise stress testing with large measurement error margins, results obtained under pathophysiologic conditions may still lie well within the 95% confidence interval of normal myocardial PCr/ATP dynamics. Current measurement precision of localized 31P-MRS for quantification of the myocardial PCr/ATP ratio precludes the detection of the changes predicted by computational modeling. This hampers clinical employment of 31P-MRS for diagnostic testing and risk stratification, and warrants developments in cardiac 31P-MRS exercise stress testing methodology.
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Affiliation(s)
- Adrianus J Bakermans
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Gustav J Strijkers
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - S Matthijs Boekholdt
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Jeroen A L Jeneson
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Neuroimaging Center, Department of Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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12
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Świątkiewicz M, Fiedorowicz M, Orzeł J, Wełniak-Kamińska M, Bogorodzki P, Langfort J, Grieb P. Increases in Brain 1H-MR Glutamine and Glutamate Signals Following Acute Exhaustive Endurance Exercise in the Rat. Front Physiol 2017; 8:19. [PMID: 28197103 PMCID: PMC5281557 DOI: 10.3389/fphys.2017.00019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 01/10/2017] [Indexed: 11/15/2022] Open
Abstract
Objective: Proton magnetic resonance spectroscopy (1H-MRS) in ultra-high magnetic field can be used for non-invasive quantitative assessment of brain glutamate (Glu) and glutamine (Gln) in vivo. Glu, the main excitatory neurotransmitter in the central nervous system, is efficiently recycled between synapses and presynaptic terminals through Glu-Gln cycle which involves glutamine synthase confined to astrocytes, and uses 60–80% of energy in the resting human and rat brain. During voluntary or involuntary exercise many brain areas are significantly activated, which certainly intensifies Glu-Gln cycle. However, studies on the effects of exercise on 1H-MRS Glu and/or Gln signals from the brain provided divergent results. The present study on rats was performed to determine changes in 1H-MRS signals from three brain regions engaged in motor activity consequential to forced acute exercise to exhaustion. Method: After habituation to treadmill running, rats were subjected to acute treadmill exercise continued to exhaustion. Each animal participating in the study was subject to two identical imaging sessions performed under light isoflurane anesthesia, prior to, and following the exercise bout. In control experiments, two imaging sessions separated by the period of rest instead of exercise were performed. 1H-NMR spectra were recorded from the cerebellum, striatum, and hippocampus using a 7T small animal MR scanner. Results: Following exhaustive exercise statistically significant increases in the Gln and Glx signals were found in all three locations, whereas increases in the Glu signal were found in the cerebellum and hippocampus. In control experiments, no changes in 1H-MRS signals were found. Conclusion: Increase in glutamine signals from the brain areas engaged in motor activity may reflect a disequilibrium caused by increased turnover in the glutamate-glutamine cycle and a delay in the return of glutamine from astrocytes to neurons. Increased turnover of Glu-Gln cycle may be a result of functional activation caused by forced endurance exercise; the increased rate of ammonia detoxification may also contribute. Increases in glutamate in the cerebellum and hippocampus are suggestive of an anaplerotic increase in glutamate synthesis due to exercise-related stimulation of brain glucose uptake. The disequilibrium in the glutamate-glutamine cycle in brain areas activated during exercise may be a significant contributor to the central fatigue phenomenon.
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Affiliation(s)
- Maciej Świątkiewicz
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of Sciences Warsaw, Poland
| | - Michał Fiedorowicz
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of Sciences Warsaw, Poland
| | - Jarosław Orzeł
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of SciencesWarsaw, Poland; Faculty of Electronics, Warsaw University of TechnologyWarsaw, Poland
| | - Marlena Wełniak-Kamińska
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of Sciences Warsaw, Poland
| | - Piotr Bogorodzki
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of SciencesWarsaw, Poland; Faculty of Electronics, Warsaw University of TechnologyWarsaw, Poland
| | - Józef Langfort
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of Sciences Warsaw, Poland
| | - Paweł Grieb
- Department of Experimental Pharmacology and Laboratory of Nuclear Magnetic Resonance Imaging, Mossakowski Medical Research Centre, Polish Academy of Sciences Warsaw, Poland
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Valkovič L, Chmelík M, Krššák M. In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism. Anal Biochem 2017; 529:193-215. [PMID: 28119063 PMCID: PMC5478074 DOI: 10.1016/j.ab.2017.01.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 01/18/2023]
Abstract
In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy (31P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of 31P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry. This paper presents a methodological overview of the 31P-MR techniques that can be used for basic, physiological, or clinical research of human skeletal muscle and liver in vivo. Practical issues of 31P-MRS experiments and examples of potential applications are also provided. As signal localization is essential for liver 31P-MRS and is important for dynamic muscle examinations as well, typical localization strategies for 31P-MR are also described.
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Affiliation(s)
- Ladislav Valkovič
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Oxford, United Kingdom; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Marek Chmelík
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Institute for Clinical Molecular MRI in Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria
| | - Martin Krššák
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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14
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Bellomo G, Marcocci F, Bianchini D, Mezzenga E, D’Errico V, Menghi E, Zannoli R, Sarnelli A. MR Spectroscopy in Prostate Cancer: New Algorithms to Optimize Metabolite Quantification. PLoS One 2016; 11:e0165730. [PMID: 27832096 PMCID: PMC5104319 DOI: 10.1371/journal.pone.0165730] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/17/2016] [Indexed: 11/18/2022] Open
Abstract
Prostate cancer (PCa) is the most common non-cutaneous cancer in male subjects and the second leading cause of cancer-related death in developed countries. The necessity of a non-invasive technique for the diagnosis of PCa in early stage has grown through years. Proton magnetic resonance spectroscopy (1H-MRS) and proton magnetic resonance spectroscopy imaging (1H-MRSI) are advanced magnetic resonance techniques that can mark the presence of metabolites such as citrate, choline, creatine and polyamines in a selected voxel, or in an array of voxels (in MRSI) inside prostatic tissue. Abundance or lack of these metabolites can discriminate between pathological and healthy tissue. Although the use of magnetic resonance spectroscopy (MRS) is well established in brain and liver with dedicated software for spectral analysis, quantification of metabolites in prostate can be very difficult to achieve, due to poor signal to noise ratio and strong J-coupling of the citrate. The aim of this work is to develop a software prototype for automatic quantification of citrate, choline and creatine in prostate. Its core is an original fitting routine that makes use of a fixed step gradient descent minimization algorithm (FSGD) and MRS simulations developed with the GAMMA libraries in C++. The accurate simulation of the citrate spin systems allows to predict the correct J-modulation under different NMR sequences and under different coupling parameters. The accuracy of the quantifications was tested on measurements performed on a Philips Ingenia 3T scanner using homemade phantoms. Some acquisitions in healthy volunteers have been also carried out to test the software performance in vivo.
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Affiliation(s)
- Giovanni Bellomo
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Francesco Marcocci
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
- * E-mail:
| | - David Bianchini
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Emilio Mezzenga
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Vincenzo D’Errico
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Enrico Menghi
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
| | - Romano Zannoli
- Experimental, Diagnostic and Specialty Medicine Department DIMES, University of Bologna, Bologna, Italy
| | - Anna Sarnelli
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy
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15
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Rafferty J, Farr L, James T, Chase D, Heinrich J, Brady M. A new magnetic resonance-based technique for high-resolution quantification of amorphous and quasi-amorphous structures. J R Soc Interface 2016; 13:rsif.2016.0589. [PMID: 27733695 DOI: 10.1098/rsif.2016.0589] [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: 07/26/2016] [Accepted: 09/12/2016] [Indexed: 11/12/2022] Open
Abstract
We present a novel, high-resolution magnetic resonance technique, fine structure analysis (FSA) for the quantification and analysis of amorphous and quasi-amorphous biological structures. The one-dimensional technique is introduced mathematically and then applied to one simulated phantom, two physical phantoms and a set of ex vivo biological samples, scanned with interpoint spacings of 0.0038-0.195 mm and cross-sectional sizes of 3 × 3 or 5 × 5 mm. The simulated phantom and one of the physical phantoms consists of randomly arranged beads of known size in two and three dimensions, respectively. The second physical phantom was constructed by etching lines on Perspex. The ex vivo samples are human bone specimens. We show that for all three phantoms, the FSA technique is able to elucidate the average spacing of the structures present within each sample using structural spectroscopy, the smallest of which was 180 µm in size. We further show that in samples of trabecular bone, FSA is able to produce comparable results to micro-computed tomography, the current gold standard for measuring bone microstructure, but without the need for ionizing radiation. Many biological structures are too small to be captured by conventional, clinically deployed medical imaging techniques. FSA has the potential for use in the analysis of pathologies where such small-scale repeating structures are disrupted or their size, and spacing is otherwise altered.
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Affiliation(s)
- James Rafferty
- Acuitas Medical Ltd, 8 Technium 1, Kings Road, Swansea SA1 8PH, UK
| | - Lance Farr
- Acuitas Medical Ltd, 8 Technium 1, Kings Road, Swansea SA1 8PH, UK
| | - Tim James
- Cbrite Inc., 421 Pine Avenue, Goleta, CA 93117, USA
| | - David Chase
- Vareda Engineering Inc., 144 Santa Felicia Drive, Goleta, CA 93117, USA
| | - John Heinrich
- Acuitas Medical Ltd, 8 Technium 1, Kings Road, Swansea SA1 8PH, UK
| | - Michael Brady
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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16
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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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17
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Bakermans AJ, Abdurrachim D, van Nierop BJ, Koeman A, van der Kroon I, Baartscheer A, Schumacher CA, Strijkers GJ, Houten SM, Zuurbier CJ, Nicolay K, Prompers JJ. In vivo mouse myocardial (31)P MRS using three-dimensional image-selected in vivo spectroscopy (3D ISIS): technical considerations and biochemical validations. NMR IN BIOMEDICINE 2015; 28:1218-1227. [PMID: 26269430 PMCID: PMC4573916 DOI: 10.1002/nbm.3371] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 06/24/2015] [Accepted: 07/09/2015] [Indexed: 05/31/2023]
Abstract
(31)P MRS provides a unique non-invasive window into myocardial energy homeostasis. Mouse models of cardiac disease are widely used in preclinical studies, but the application of (31)P MRS in the in vivo mouse heart has been limited. The small-sized, fast-beating mouse heart imposes challenges regarding localized signal acquisition devoid of contamination with signal originating from surrounding tissues. Here, we report the implementation and validation of three-dimensional image-selected in vivo spectroscopy (3D ISIS) for localized (31)P MRS of the in vivo mouse heart at 9.4 T. Cardiac (31)P MR spectra were acquired in vivo in healthy mice (n = 9) and in transverse aortic constricted (TAC) mice (n = 8) using respiratory-gated, cardiac-triggered 3D ISIS. Localization and potential signal contamination were assessed with (31)P MRS experiments in the anterior myocardial wall, liver, skeletal muscle and blood. For healthy hearts, results were validated against ex vivo biochemical assays. Effects of isoflurane anesthesia were assessed by measuring in vivo hemodynamics and blood gases. The myocardial energy status, assessed via the phosphocreatine (PCr) to adenosine 5'-triphosphate (ATP) ratio, was approximately 25% lower in TAC mice compared with controls (0.76 ± 0.13 versus 1.00 ± 0.15; P < 0.01). Localization with one-dimensional (1D) ISIS resulted in two-fold higher PCr/ATP ratios than measured with 3D ISIS, because of the high PCr levels of chest skeletal muscle that contaminate the 1D ISIS measurements. Ex vivo determinations of the myocardial PCr/ATP ratio (0.94 ± 0.24; n = 8) confirmed the in vivo observations in control mice. Heart rate (497 ± 76 beats/min), mean arterial pressure (90 ± 3.3 mmHg) and blood oxygen saturation (96.2 ± 0.6%) during the experimental conditions of in vivo (31)P MRS were within the normal physiological range. Our results show that respiratory-gated, cardiac-triggered 3D ISIS allows for non-invasive assessments of in vivo mouse myocardial energy homeostasis with (31)P MRS under physiological conditions.
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Affiliation(s)
- Adrianus J. Bakermans
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Bastiaan J. van Nierop
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Anneke Koeman
- Laboratory of Experimental Intensive Care and Anesthesiology, Department of Anesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Inge van der Kroon
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Antonius Baartscheer
- Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Cees A. Schumacher
- Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Gustav J. Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Sander M. Houten
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, and Department of Pediatrics, Emma Children’s Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Coert J. Zuurbier
- Laboratory of Experimental Intensive Care and Anesthesiology, Department of Anesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jeanine J. Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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18
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Bakermans AJ, Abdurrachim D, Moonen RPM, Motaal AG, Prompers JJ, Strijkers GJ, Vandoorne K, Nicolay K. Small animal cardiovascular MR imaging and spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 88-89:1-47. [PMID: 26282195 DOI: 10.1016/j.pnmrs.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
The use of MR imaging and spectroscopy for studying cardiovascular disease processes in small animals has increased tremendously over the past decade. This is the result of the remarkable advances in MR technologies and the increased availability of genetically modified mice. MR techniques provide a window on the entire timeline of cardiovascular disease development, ranging from subtle early changes in myocardial metabolism that often mark disease onset to severe myocardial dysfunction associated with end-stage heart failure. MR imaging and spectroscopy techniques play an important role in basic cardiovascular research and in cardiovascular disease diagnosis and therapy follow-up. This is due to the broad range of functional, structural and metabolic parameters that can be quantified by MR under in vivo conditions non-invasively. This review describes the spectrum of MR techniques that are employed in small animal cardiovascular disease research and how the technological challenges resulting from the small dimensions of heart and blood vessels as well as high heart and respiratory rates, particularly in mice, are tackled.
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Affiliation(s)
- Adrianus J Bakermans
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Rik P M Moonen
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Abdallah G Motaal
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Katrien Vandoorne
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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Schaller B, Clarke WT, Neubauer S, Robson MD, Rodgers CT. Suppression of skeletal muscle signal using a crusher coil: A human cardiac (31) p-MR spectroscopy study at 7 tesla. Magn Reson Med 2015; 75:962-72. [PMID: 25924813 PMCID: PMC4762536 DOI: 10.1002/mrm.25755] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 12/19/2022]
Abstract
Purpose The translation of sophisticated phosphorus MR spectroscopy (31P‐MRS) protocols to 7 Tesla (T) is particularly challenged by the issue of radiofrequency (RF) heating. Legal limits on RF heating make it hard to reliably suppress signals from skeletal muscle that can contaminate human cardiac 31P spectra at 7T. We introduce the first surface‐spoiling crusher coil for human cardiac 31P‐MRS at 7T. Methods A planar crusher coil design was optimized with simulations and its performance was validated in phantoms. Crusher gradient pulses (100 μs) were then applied during human cardiac 31P‐MRS at 7T. Results In a phantom, residual signals were 50 ± 10% with BISTRO (B1‐insensitive train to obliterate signal), and 34 ± 8% with the crusher coil. In vivo, residual signals in skeletal muscle were 49 ± 4% using BISTRO, and 24 ± 5% using the crusher coil. Meanwhile, in the interventricular septum, spectral quality and metabolite quantification did not differ significantly between BISTRO (phosphocreatine/adenosine triphosphate [PCr/ATP] = 2.1 ± 0.4) and the crusher coil (PCr/ATP = 1.8 ± 0.4). However, the specific absorption rate (SAR) decreased from 96 ± 1% of the limit (BISTRO) to 16 ± 1% (crusher coil). Conclusion A crusher coil is an SAR‐efficient alternative for selectively suppressing skeletal muscle during cardiac 31P‐MRS at 7T. A crusher coil allows the use of sequence modules that would have been SAR‐prohibitive, without compromising skeletal muscle suppression. Magn Reson Med 75:962–972, 2016. © 2015 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance.
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Affiliation(s)
- Benoit Schaller
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - William T Clarke
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Stefan Neubauer
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Matthew D Robson
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Christopher T Rodgers
- University of Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
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20
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Powell NJ, Jang A, Park JY, Valette J, Garwood M, Marjańska M. Gradient rotating outer volume excitation (GROOVE): A novel method for single-shot two-dimensional outer volume suppression. Magn Reson Med 2015; 73:139-49. [PMID: 24478130 PMCID: PMC4115059 DOI: 10.1002/mrm.25101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 12/05/2013] [Accepted: 12/06/2013] [Indexed: 11/06/2022]
Abstract
PURPOSE To introduce a new outer volume suppression (OVS) technique that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called gradient rotating outer volume excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing the entire outer volume. METHODS Theoretical and k-space descriptions of GROOVE are provided. The properties of GROOVE were investigated with simulations, phantom, and human experiments performed using a 4T horizontal bore magnet equipped with a TEM coil. RESULTS Similar suppression performance was obtained in phantom and human brain using GROOVE with circular and elliptical shapes. Simulations indicate that GROOVE requires less SAR and time than traditional OVS schemes, but traditional schemes provide a sharper transition zone and less residual signal. CONCLUSION GROOVE represents a new way of performing OVS in which spins are excited temporally in space on a trajectory that can be tailored to fit the shape of the suppression region. In addition, GROOVE is capable of suppressing tailored regions of space with more flexibility and in a shorter period of time than conventional methods. GROOVE provides a fast, low SAR alternative to conventional OVS methods in some applications (e.g., scalp suppression).
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Affiliation(s)
- Nathaniel J. Powell
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 6 ST SE, Minneapolis, Minnesota 55455, United States
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Albert Jang
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 6 ST SE, Minneapolis, Minnesota 55455, United States
- Department of Electrical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jang-Yeon Park
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Biomedical and Health Science, Konkuk University, Chungju, South Korea
| | - Julien Valette
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 6 ST SE, Minneapolis, Minnesota 55455, United States
- Commissariat à l'Energie Atomique (CEA), Molecular Imaging Research Center (MIRCen), 18 route du panorama, BP n°6, F-92265, Fontenay-aux-Roses, France
| | - Michael Garwood
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 6 ST SE, Minneapolis, Minnesota 55455, United States
| | - Małgorzata Marjańska
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 6 ST SE, Minneapolis, Minnesota 55455, United States
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Tal A, Gonen O. Spectroscopic localization by simultaneous acquisition of the double-spin and stimulated echoes. Magn Reson Med 2014; 73:31-43. [PMID: 24664399 DOI: 10.1002/mrm.25112] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 12/11/2013] [Accepted: 12/12/2013] [Indexed: 12/17/2022]
Abstract
PURPOSE To design a proton MR spectroscopy ((1) H-MRS) localization sequence that combines the signal-to-noise-ratio (SNR) benefits of point resolved spectroscopy (PRESS) with the high pulse bandwidths, low chemical shift displacements (CSD), low specific absorption rates (SAR), short echo times (TE), and superior radiofrequency transmit field (B1+) immunity of stimulated echo acquisition mode (STEAM), by simultaneously refocusing and acquiring both the double-spin and stimulated echo coherence pathways from the volume of interest. THEORY AND METHODS We propose a family of (1)H-MRS sequences comprising three orthogonal spatially selective pulses with flip angles 90° < α, β, γ < 128°. The stimulated and double-spin echo are refocused in-phase simultaneously by altering the pulses' phases, flip angles and timing, as well as the interpulse gradient spoiling moments. The ≈ 90° nutations of α, β, γ provide STEAM-like advantages (lower SAR, in-plane CSD and TE; greater B1+ immunity), but with SNRs comparable with PRESS. RESULTS Phantom and in vivo brain experiments show that 83-100% of the PRESS SNR (metabolite-dependent) is achieved at under 75% of the SAR and 66% lower in-plane CSD. CONCLUSION The advantages of STEAM can be augmented with the higher SNR of PRESS by combining the spin and stimulated echoes. Quantification, especially of J-coupled resonances and intermediate and long TEs, must be carefully considered.
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Affiliation(s)
- Assaf Tal
- Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Oded Gonen
- Department of Radiology, New York University School of Medicine, New York, New York, USA
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Chmelík M, Kukurová IJ, Gruber S, Krššák M, Valkovič L, Trattnig S, Bogner W. Fully adiabatic 31P 2D-CSI with reduced chemical shift displacement error at 7 T--GOIA-1D-ISIS/2D-CSI. Magn Reson Med 2012; 69:1233-44. [PMID: 22714782 DOI: 10.1002/mrm.24363] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 04/24/2012] [Accepted: 05/14/2012] [Indexed: 12/24/2022]
Abstract
A fully adiabatic phosphorus (31P) two-dimensional (2D) chemical shift spectroscopic imaging sequence with reduced chemical shift displacement error for 7 T, based on 1D-image-selected in vivo spectroscopy, combined with 2D-chemical shift spectroscopic imaging selection, was developed. Slice-selective excitation was achieved by a spatially selective broadband GOIA-W(16,4) inversion pulse with an interleaved subtraction scheme before nonselective adiabatic excitation, and followed by 2D phase encoding. The use of GOIA-W(16,4) pulses (bandwidth 4.3-21.6 kHz for 10-50 mm slices) reduced the chemical shift displacement error in the slice direction ∼1.5-7.7 fold, compared to conventional 2D-chemical shift spectroscopic imaging with Sinc3 selective pulses (2.8 kHz). This reduction was experimentally demonstrated with measurements of an MR spectroscopy localization phantom and with experimental evaluation of pulse profiles. In vivo experiments in clinically acceptable measurement times were demonstrated in the calf muscle (nominal voxel volume, 5.65 ml in 6 min 53 s), brain (10 ml, 6 min 32 s), and liver (8.33 ml, 8 min 14 s) of healthy volunteers at 7 T. High reproducibility was found in the calf muscle at 7 T. In combination with adiabatic excitation, this sequence is insensitive to the B1 inhomogeneities associated with surface coils. This sequence, which is termed GOIA-1D-ISIS/2D-CSI (goISICS), has the potential to be applied in both clinical research and in the clinical routine.
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Affiliation(s)
- M Chmelík
- MR Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria
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N-Acetyl peak in proton MR spectroscopy of metastatic mucinous adenocarcinoma of brain. Clin Neuroradiol 2012; 23:153-6. [DOI: 10.1007/s00062-012-0137-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 01/27/2012] [Indexed: 12/15/2022]
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Hamilton G, Smith DL, Bydder M, Nayak KS, Hu HH. MR properties of brown and white adipose tissues. J Magn Reson Imaging 2012; 34:468-73. [PMID: 21780237 DOI: 10.1002/jmri.22623] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To explore the MR signatures of brown adipose tissue (BAT) compared with white adipose tissue (WAT) using single-voxel MR spectroscopy. MATERIALS AND METHODS (1) H MR STEAM spectra were acquired from a 3 Tesla clinical whole body scanner from seven excised murine adipose tissue samples of BAT (n=4) and WAT (n=3). Spectra were acquired at multiple echo times (TEs) and inversion times (TIs) to measure the T1, T2, and T2-corrected peak areas. A theoretical triglyceride model characterized the fat in terms of number of double bonds (ndb) and number of methylene-interrupted double bonds (nmidb). RESULTS Negligible differences between WAT and BAT were seen in the T1 and T2 of fat and the T2 of water. However, the water fraction in BAT was higher (48.5%) compared with WAT (7.1%) and the T1 of water was lower in BAT (618 ms) compared with WAT (1053 ms). The fat spectrum also differed, indicating lower levels of unsaturated triglycerides in BAT (ndb=2.7, nmidb=0.7) compared with WAT (ndb=3.3, nmidb=1.0). CONCLUSION We have demonstrated that there are several key MR-based signatures of BAT and WAT that may allow differentiation on MR imaging.
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Affiliation(s)
- Gavin Hamilton
- Department of Radiology, University of California, San Diego, San Diego, California, USA
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Hamilton G, Yokoo T, Bydder M, Cruite I, Schroeder ME, Sirlin CB, Middleton MS. In vivo characterization of the liver fat ¹H MR spectrum. NMR IN BIOMEDICINE 2011; 24:784-90. [PMID: 21834002 PMCID: PMC3860876 DOI: 10.1002/nbm.1622] [Citation(s) in RCA: 398] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 08/17/2010] [Accepted: 08/30/2010] [Indexed: 05/13/2023]
Abstract
A theoretical triglyceride model was developed for in vivo human liver fat (1) H MRS characterization, using the number of double bonds (-CH=CH-), number of methylene-interrupted double bonds (-CH=CH-CH(2)-CH=CH-) and average fatty acid chain length. Five 3 T, single-voxel, stimulated echo acquisition mode spectra (STEAM) were acquired consecutively at progressively longer TEs in a fat-water emulsion phantom and in 121 human subjects with known or suspected nonalcoholic fatty liver disease. T(2)-corrected peak areas were calculated. Phantom data were used to validate the model. Human data were used in the model to determine the complete liver fat spectrum. In the fat-water emulsion phantom, the spectrum predicted by the model (based on known fatty acid chain distribution) agreed closely with spectroscopic measurement. In human subjects, areas of CH(2) peaks at 2.1 and 1.3 ppm were linearly correlated (slope, 0.172; r = 0.991), as were the 0.9 ppm CH(3) and 1.3 ppm CH(2) peaks (slope, 0.125; r = 0.989). The 2.75 ppm CH(2) peak represented 0.6% of the total fat signal in high-liver-fat subjects. These values predict that 8.6% of the total fat signal overlies the water peak. The triglyceride model can characterize human liver fat spectra. This allows more accurate determination of liver fat fraction from MRI and MRS.
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Affiliation(s)
- Gavin Hamilton
- Department of Radiology, University of California, San Diego, CA 92103-8749, USA
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Bogner W, Chmelik M, Andronesi OC, Sorensen AG, Trattnig S, Gruber S. In vivo 31P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: a comparison between 3 T and 7 T. Magn Reson Med 2011; 66:923-30. [PMID: 21446033 DOI: 10.1002/mrm.22897] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 02/01/2011] [Accepted: 02/06/2011] [Indexed: 01/11/2023]
Abstract
An improved image selected in vivo spectroscopy (ISIS) sequence for localized (31)P magnetic resonance spectroscopy at 7 T was developed. To reduce errors in localization accuracy, adiabatic excitation, gradient offset independent adiabatic inversion pulses, and a special extended ISIS ordering scheme were used. The localization accuracy of extended ISIS was investigated in phantoms. The possible spectral quality and reproducibility in vivo was explored in a volunteer (brain, muscle, and liver). A comparison between 3 T and 7 T was performed in five volunteers. Adiabatic extended ISIS provided high spectral quality and accurate localization. The contamination in phantom experiments was only ∼5%, even if a pulse repetition time ∼ 1.2·T(1) was chosen to maximize the signal-to-noise ratio per unit time. High reproducibility was found in the calf muscle for 2.5 cm isotropic voxels at 7 T. When compared with 3 T, localized (31)P magnetic resonance spectroscopy in the human calf muscle at 7 T provided ∼3.2 times higher signal-to-noise ratio (as judged from phosphocreatine peak amplitude in frequency domain after matched filtering). At 7 T, extended ISIS allowed the performance of high-quality localized (31)P magnetic resonance spectroscopy in a short measurement time (∼3 to 4 min) and isotropic voxel sizes of ∼2.5 to 3 cm. With such short measurement times, localized (31)P magnetic resonance spectroscopy has the potential to be applied not only for clinical research but also for routine clinical practice.
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Affiliation(s)
- W Bogner
- Department of Radiology, MR Center of Excellence, Medical University Vienna, Vienna, Austria
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Kuo AYC, Chiew M, Tam F, Cunningham C, Graham SJ. Multiecho coarse voxel acquisition for neurofeedback fMRI. Magn Reson Med 2010; 65:715-24. [DOI: 10.1002/mrm.22674] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 08/23/2010] [Accepted: 09/14/2010] [Indexed: 11/08/2022]
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N-Acetyl peak in MR spectra of intracranial metastatic mucinous adenocarcinomas. Magn Reson Imaging 2010; 28:1390-4. [PMID: 20797831 DOI: 10.1016/j.mri.2010.06.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 04/16/2010] [Accepted: 06/25/2010] [Indexed: 11/20/2022]
Abstract
Absence of N-acetylaspartate (NAA) is one important diagnostic criterion of MR spectroscopy (MRS) that may suggest that an intracranial mass lesion is a metastasis. We report two cases of histopathology-confirmed intracranial metastatic mucinous adenocarcinoma, which predominantly showed a large metabolite peak at 2.0 ppm, mimicking an NAA peak of normal brain tissue. This finding could be of help in the interpretation of MRS in cases of intracranial enhancing mass lesions, metastases or gliomas.
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Mantel C, Bayle PA, Hediger S, Berthon C, Bardet M. Study of liquid-liquid interfaces by an easily implemented localized NMR sequence. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48:600-606. [PMID: 20589724 DOI: 10.1002/mrc.2628] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
To selectively extract heavy metals from solutions containing fission products, it is essential to optimize the liquid-liquid extraction processes. Such an objective requires improving the fundamental knowledge of the different mechanisms that are involved in these processes. In that respect, we propose a localized NMR sequence named LOCSY to assess the concentration profiles of different species involved in these processes. One of the goals of this sequence is to study the products as close as possible to the liquid-liquid interface with the help of a standard NMR spectrometer of chemistry labs. The one-dimensional spatial localization along the NMR tube is obtained by a discrete stepping of the frequency-selective excitation pulses under a pulsed field gradient. Specific data processing has been developed to obtain the 1D NMR spectra as a function of the vertical position in the NMR tube. The LOCSY sequence has been tested and evaluated on three different systems: (i) a cylindrical phantom inserted in the NMR tube containing 4-methylsalicylic acid solution, (ii) D(2)O/olive oil biphasic system, and (iii) the dissolution of solid saccharose in D(2)O. These examples illustrate potential applications of the LOCSY sequence, particularly the possibility to measure concentration profiles and to study phenomena such as diffusion, provided the dynamic range is compatible with NMR timescale and sensitivity.
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Affiliation(s)
- Claire Mantel
- CEA, INAC, SCIB, Laboratoire de Résonances Magnétiques, UMR-E3 CEA-UJF, FRE 3200 CEA-CNRS, F-38054 Grenoble, France
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Melkus G, Mörchel P, Behr VC, Kotas M, Flentje M, Jakob PM. Sensitive J-coupled metabolite mapping using Sel-MQC with selective multi-spin-echo readout. Magn Reson Med 2010; 62:880-7. [PMID: 19750545 DOI: 10.1002/mrm.22108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The selective multiple quantum coherence technique is combined with a read gradient to accelerate the measurement of a specific scalar-coupled metabolite. The sensitivities of the localization using pure phase encoding and localization with the read gradient are compared in experiments at high magnetic field strength (17.6 T). Multiple spin-echoes of the selective multiple quantum coherence edited metabolite are acquired using frequency-selective refocusing of the specified molecule group. The frequency-selective refocusing does not affect the J-modulation of a coupled spin system, and the echo time is not limited to a multiple of 1/J to acquire pure in-phase or antiphase signal. The multiple echoes can be used to accelerate the metabolite imaging experiment or to measure the apparent transverse relaxation T(2). A simple phase-shifting scheme is presented, which enables the suppression of editing artifacts resulting from the multiple spin-echoes of the water resonance. The experiments are carried out on phantoms, in which lactate and polyunsaturated fatty acids are edited, and in vivo on tumors, in which lactate content and T(2) are imaged. The method is of particular interest when a fast and sensitive selective multiple quantum coherence editing is necessary, e.g., for spatial three dimensional experiments.
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Affiliation(s)
- Gerd Melkus
- Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany.
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Lambert J, Hergenröder R, Suter D, Deckert V. Probing Liquid-Liquid Interfaces with Spatially Resolved NMR Spectroscopy. Angew Chem Int Ed Engl 2009; 48:6343-5. [DOI: 10.1002/anie.200901389] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Lambert J, Hergenröder R, Suter D, Deckert V. Untersuchung von Flüssig-flüssig-Phasengrenzen mit ortsauflösender NMR-Spektroskopie. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200901389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hamilton G, Middleton MS, Bydder M, Yokoo T, Schwimmer JB, Kono Y, Patton HM, Lavine JE, Sirlin CB. Effect of PRESS and STEAM sequences on magnetic resonance spectroscopic liver fat quantification. J Magn Reson Imaging 2009; 30:145-52. [PMID: 19557733 PMCID: PMC2982807 DOI: 10.1002/jmri.21809] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To compare PRESS and STEAM MR spectroscopy for assessment of liver fat in human subjects. MATERIALS AND METHODS Single-voxel (20 x 20 x 20 mm) PRESS and STEAM spectra were obtained at 1.5T in 49 human subjects with known or suspected fatty liver disease. PRESS and STEAM sequences were obtained with fixed TR (1500 msec) and different TE (five PRESS spectra between TE 30-70 msec, five STEAM spectra between TE 20-60 msec). Spectra were quantified and T2 and T2-corrected peak area were calculated by different techniques. The values were compared for PRESS and STEAM. RESULTS Water T2 values from PRESS and STEAM were not significantly different (P = 0.33). Fat peak T2s were 25%-50% shorter on PRESS than on STEAM (P < 0.02 for all comparisons) and there was no correlation between T2s of individual peaks. PRESS systematically overestimated the relative fat peak areas (by 7%-263%) compared to STEAM (P < 0.005 for all comparisons). The peak area given by PRESS was more dependent on the T2-correction technique than STEAM. CONCLUSION Measured liver fat depends on the MRS sequence used. Compared to STEAM, PRESS underestimates T2 values of fat, overestimates fat fraction, and provides a less consistent fat fraction estimate, probably due to J coupling effects.
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Affiliation(s)
- Gavin Hamilton
- Department of Radiology, University of California, San Diego, San Diego, California 92103-8226, USA
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Jissendi Tchofo P, Balériaux D. Brain 1H-MR spectroscopy in clinical neuroimaging at 3T. J Neuroradiol 2009; 36:24-40. [DOI: 10.1016/j.neurad.2008.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Brain lithium levels and effects on cognition and mood in geriatric bipolar disorder: a lithium-7 magnetic resonance spectroscopy study. Am J Geriatr Psychiatry 2009; 17:13-23. [PMID: 18626002 PMCID: PMC4085782 DOI: 10.1097/jgp.0b013e318172b3d0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The authors investigated the relationship between brain lithium, serum lithium and age in adult subjects treated with lithium. In addition, the authors investigated the association between brain lithium and serum lithium with frontal lobe functioning and mood in a subgroup of older subjects. DESIGN Cross-sectional assessment. SETTING McLean Hospital's Geriatric Psychiatry Research Program and Brain Imaging Center; The Division of Psychiatry, Boston University School of Medicine. PARTICIPANTS Twenty-six subjects, 20 to 85 years, with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-TR bipolar disorder (BD), currently treated with lithium. MEASUREMENTS All subjects had measurements of mood (Hamilton Depression Rating Scale [HDRS] and Young Mania Rating Scale) and serum and brain lithium levels. Brain lithium levels were assessed using lithium Magnetic Resonance Spectroscopy. Ten subjects older than 50 years also had assessments of frontal lobe functioning (Stroop, Trails A and B, Wis. Card Sorting Task). RESULTS Brain lithium levels correlated with serum lithium levels for the group as a whole. However, this relationship was not present for the group of subjects older than 50. For these older subjects elevations in brain (but not serum) lithium levels were associated with frontal lobe dysfunction and higher HDRS scores. The higher HDRS were associated with increased somatic symptoms. CONCLUSION Frontal lobe dysfunction and elevated depression symptoms correlating with higher brain lithium levels supports conservative dosing recommendations in bipolar older adults. The absence of a predictable relationship between serum and brain lithium makes specific individual predictions about the "ideal" lithium serum level in an older adult with BD difficult.
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Soares DP, Law M. Magnetic resonance spectroscopy of the brain: review of metabolites and clinical applications. Clin Radiol 2008; 64:12-21. [PMID: 19070693 DOI: 10.1016/j.crad.2008.07.002] [Citation(s) in RCA: 278] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 07/01/2008] [Accepted: 07/08/2008] [Indexed: 01/22/2023]
Abstract
Magnetic resonance imaging (MRI) provides anatomic images and morphometric characterization of disease, whereas magnetic resonance spectroscopy (MRS) provides metabolite/biochemical information about tissues non-invasively in vivo. MRS has been used clinically for more than two decades. The major applications of this advanced MRI tool are in the investigation of neurological and neurosurgical disorders. MRS has also been used in the evaluation of the prostate gland and muscle tissue, but these applications will not be addressed in this review. The aim of this review is to attempt to introduce the technique, review the metabolites and literature, as well as briefly describe our clinical experience.
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Affiliation(s)
- D P Soares
- Section of Radiology, Department of Surgery, Radiology, Anaesthetics, and Intensive Care, University Hospital of the West Indies, Mona, Kingston, Jamaica.
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Saneto RP, Friedman SD, Shaw DWW. Neuroimaging of mitochondrial disease. Mitochondrion 2008; 8:396-413. [PMID: 18590986 DOI: 10.1016/j.mito.2008.05.003] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 05/11/2008] [Accepted: 05/14/2008] [Indexed: 10/22/2022]
Abstract
Mitochondrial disease represents a heterogeneous group of genetic disorders that require a variety of diagnostic tests for proper determination. Neuroimaging may play a significant role in diagnosis. The various modalities of nuclear magnetic resonance imaging (MRI) allow for multiple independent detection procedures that can give important anatomical and metabolic clues for diagnosis. The non-invasive nature of neuroimaging also allows for longitudinal studies. To date, no pathonmonic correlation between specific genetic defect and neuroimaging findings have been described. However, certain neuroimaging results can give important clues that a patient may have a mitochondrial disease. Conventional MRI may show deep gray structural abnormalities or stroke-like lesions that do not respect vascular territories. Chemical techniques such as proton magnetic resonance spectroscopy (MRS) may demonstrate high levels of lactate or succinate. When found, these results are suggestive of a mitochondrial disease. MRI and MRS studies may also show non-specific findings such as delayed myelination or non-specific leukodystrophy picture. However, in the context of other biochemical, structural, and clinical findings, even non-specific findings may support further diagnostic testing for potential mitochondrial disease. Once a diagnosis has been established, these non-invasive tools can also aid in following disease progression and evaluate the effects of therapeutic interventions.
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Affiliation(s)
- Russell P Saneto
- Division of Pediatric Neurology, Children's Hospital and Regional Medical Center/University of Washington, 4800 Sand Point Way NE, Seattle, WA 98105, USA.
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Vaidyanathan S, Fletcher JS, Goodacre R, Lockyer NP, Micklefield J, Vickerman JC. Subsurface Biomolecular Imaging of Streptomyces coelicolor Using Secondary Ion Mass Spectrometry. Anal Chem 2008; 80:1942-51. [DOI: 10.1021/ac701921e] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Seetharaman Vaidyanathan
- School of Chemical Engineering and Analytical Sciences, and School of Chemistry, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - John S. Fletcher
- School of Chemical Engineering and Analytical Sciences, and School of Chemistry, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Roy Goodacre
- School of Chemical Engineering and Analytical Sciences, and School of Chemistry, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Nicholas P. Lockyer
- School of Chemical Engineering and Analytical Sciences, and School of Chemistry, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Jason Micklefield
- School of Chemical Engineering and Analytical Sciences, and School of Chemistry, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - John C. Vickerman
- School of Chemical Engineering and Analytical Sciences, and School of Chemistry, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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Abstract
Over the past two decades, proton magnetic resonance spectroscopy (proton MRS) of the brain has made the transition from research tool to a clinically useful modality. In this review, we first describe the localization methods currently used in MRS studies of the brain and discuss the technical and practical factors that determine the applicability of the methods to particular clinical studies. We also describe each of the resonances detected by localized solvent-suppressed proton MRS of the brain and discuss the metabolic and biochemical information that can be derived from an analysis of their concentrations. We discuss spectral quantitation and summarize the reproducibility of both single-voxel and multivoxel methods at 1.5 and 3-4 T. We have selected three clinical neurologic applications in which there has been a consensus as to the diagnostic value of MRS and summarize the information relevant to clinical applications. Finally, we speculate about some of the potential technical developments, either in progress or in the future, that may lead to improvements in the performance of proton MRS.
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Affiliation(s)
- Yael Rosen
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 02215 Boston, Massachusetts
| | - Robert E. Lenkinski
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 02215 Boston, Massachusetts
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Cecil KM, Kos RS. Magnetic resonance spectroscopy and metabolic imaging in white matter diseases and pediatric disorders. Top Magn Reson Imaging 2007; 17:275-93. [PMID: 17415001 DOI: 10.1097/rmr.0b013e318033787e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This review provides the reader with an overview of the magnetic resonance spectroscopy technique and the clinical, pathological, imaging, and metabolic features for select white matter disorders of interest. With this composite summary, the reader should find it easier to implement and interpret spectroscopy in the clinical setting for the diagnosis and monitoring of patients with white matter disorders.
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Affiliation(s)
- Kim M Cecil
- Department of Radiology and Pediatrics, Cincinnati Children's Hospital Medical Center and the College of Medicine of the University of Cincinnati, Cincinnati, OH 45229, USA.
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