1
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Graf C, Stollberger R, Rund A, Schweiger M, Diwoky C. Robust dual-angle T 1 $$ {T}_1 $$ measurement in magnetization transfer spectroscopy by time-optimal control. NMR IN BIOMEDICINE 2024:e5151. [PMID: 38583871 DOI: 10.1002/nbm.5151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/07/2024] [Accepted: 03/01/2024] [Indexed: 04/09/2024]
Abstract
Magnetization transfer spectroscopy relies heavily on the robust determination ofT 1 $$ {T}_1 $$ relaxation times of nuclei participating in metabolic exchange. Challenges arise due to the use of surface RF coils for transmission (highB 1 + $$ {B}_1^{+} $$ variation) and the broad resonance band of most X nuclei. These challenges are particularly pronounced when fastT 1 $$ {T}_1 $$ mapping methods, such as the dual-angle method, are employed. Consequently, in this work, we develop resonance offset andB 1 + $$ {B}_1^{+} $$ robust excitation RF pulses for 31P magnetization transfer spectroscopy at 7T through ensemble-based time-optimal control. In our approach, we introduce a cost functional for designing robust pulses, incorporating the full Bloch equations as constraints, which are solved using symmetric operator splitting techniques. The optimal control design of the RF pulses developed demonstrates improved accuracy, desired phase properties, and reduced RF power when applied to dual-angleT 1 $$ {T}_1 $$ mapping, thereby improving the precision of exchange-rate measurements, as demonstrated in a preclinical in vivo study quantifying brain creatine kinase activity.
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Affiliation(s)
- Christina Graf
- Institute of Biomedical Imaging, Graz University of Technology, Graz, Austria
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
| | - Rudolf Stollberger
- Institute of Biomedical Imaging, Graz University of Technology, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Armin Rund
- Institute for Mathematics and Scientific Computing, Karl-Franzens University Graz, Graz, Austria
| | - Martina Schweiger
- BioTechMed-Graz, Graz, Austria
- Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria
- Field of Excellence BioHealthKarl-Franzens University Graz, Graz, Austria
| | - Clemens Diwoky
- Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria
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2
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Widmaier M, Lim SI, Wenz D, Xin L. Fast in vivo assay of creatine kinase activity in the human brain by 31 P magnetic resonance fingerprinting. NMR IN BIOMEDICINE 2023; 36:e4998. [PMID: 37424110 DOI: 10.1002/nbm.4998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 05/15/2023] [Accepted: 06/12/2023] [Indexed: 07/11/2023]
Abstract
A new and efficient magnetisation transfer 31 P magnetic resonance fingerprinting (MT-31 P-MRF) approach is introduced to measure the creatine kinase metabolic ratek CK between phosphocreatine (PCr) and adenosine triphosphate (ATP) in human brain. The MRF framework is extended to overcome challenges in conventional 31 P measurement methods in the human brain, enabling reduced acquisition time and specific absorption rate (SAR). To address the challenge of creating and matching large multiparametric dictionaries in an MRF scheme, a nested iteration interpolation method (NIIM) is introduced. As the number of parameters to estimate increases, the size of the dictionary grows exponentially. NIIM can reduce the computational load by breaking dictionary matching into subsolutions of linear computational order. MT-31 P-MRF combined with NIIM providesT 1 PCr ,T 1 ATP andk CK estimates in good agreement with those obtained by the exchange kinetics by band inversion transfer (EBIT) method and literature values. Furthermore, the test-retest reproducibility results showed that MT-31 P-MRF achieves a similar or better coefficient of variation (<12%) forT 1 ATP andk CK measurements in 4 min 15 s, than EBIT with 17 min 4 s scan time, enabling a fourfold reduction in scan time. We conclude that MT-31 P-MRF in combination with NIIM is a fast, accurate, and reproducible approach for in vivok CK assays in the human brain, which enables the potential to investigate energy metabolism in a clinical setting.
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Affiliation(s)
- Mark Widmaier
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Laboratory for Functional and Metabolic Imaging, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Song-I Lim
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Laboratory for Functional and Metabolic Imaging, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Daniel Wenz
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Lijing Xin
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
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3
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van den Wildenberg L, Gursan A, Seelen LWF, van der Velden TA, Gosselink MWJM, Froeling M, van der Kemp WJM, Klomp DWJ, Prompers JJ. In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole-body transmit coil and 16-channel receive array: Repeatability and effects of principal component analysis-based denoising. NMR IN BIOMEDICINE 2023; 36:e4877. [PMID: 36400716 DOI: 10.1002/nbm.4877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Quantitative three-dimensional (3D) imaging of phosphorus (31 P) metabolites is potentially a promising technique with which to assess the progression of liver disease and monitor therapy response. However, 31 P magnetic resonance spectroscopy has a low sensitivity and commonly used 31 P surface coils do not provide full coverage of the liver. This study aimed to overcome these limitations by using a 31 P whole-body transmit coil in combination with a 16-channel 31 P receive array at 7 T. Using this setup, we determined the repeatability of whole-liver 31 P magnetic resonance spectroscopic imaging (31 P MRSI) in healthy subjects and assessed the effects of principal component analysis (PCA)-based denoising on the repeatability parameters. In addition, spatial variations of 31 P metabolites within the liver were analyzed. 3D 31 P MRSI data of the liver were acquired with a nominal voxel size of 20 mm isotropic in 10 healthy volunteers twice on the same day. Data were reconstructed without denoising, and with PCA-based denoising before or after channel combination. From the test-retest data, repeatability parameters for metabolite level quantification were determined for 12 31 P metabolite signals. On average, 31 P MR spectra from 100 ± 25 voxels in the liver were analyzed. Only voxels with contamination from skeletal muscle or the gall bladder were excluded and no voxels were discarded based on (low) signal-to-noise ratio (SNR). Repeatability for most quantified 31 P metabolite levels in the liver was good to excellent, with an intrasubject variability below 10%. PCA-based denoising increased the SNR ~ 3-fold, but did not improve the repeatability for mean liver 31 P metabolite quantification with the fitting constraints used. Significant spatial heterogeneity of various 31 P metabolite levels within the liver was observed, with marked differences for the phosphomonoester and phosphodiester metabolites between the left and right lobe. In conclusion, using a 31 P whole-body transmit coil in combination with a 16-channel 31 P receive array at 7 T allowed 31 P MRSI acquisitions with full liver coverage and good to excellent repeatability.
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Affiliation(s)
| | - Ayhan Gursan
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leonard W F Seelen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tijl A van der Velden
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark W J M Gosselink
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martijn Froeling
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wybe J M van der Kemp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
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4
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Huang Z, Gambarota G, Xiao Y, Wenz D, Xin L. Apparent diffusion coefficients of 31P metabolites in the human calf muscle at 7 T. MAGMA (NEW YORK, N.Y.) 2023; 36:309-315. [PMID: 36752933 PMCID: PMC10140108 DOI: 10.1007/s10334-023-01065-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/05/2023] [Accepted: 01/19/2023] [Indexed: 04/28/2023]
Abstract
PURPOSE In this study, we aimed to measure the apparent diffusion coefficients (ADCs) of major phosphorous metabolites in the human calf muscle at 7 T with a diffusion-weighted (DW)-STEAM sequence. METHODS A DW-STEAM sequence with bipolar gradients was implemented at 7 T, and DW MR spectra were acquired in three orthogonal directions in the human calf muscle of six healthy volunteers (TE/TM/TR = 15 ms/750 ms/5 s) at three b-values (0, 800, and 1200 s/mm2). Frequency and phase alignments were applied prior to spectral averaging. Averaged DW MR spectra were analyzed with LCModel, and ADCs of 31P metabolites were estimated. RESULTS Four metabolites (phosphocreatine (PCr), adenosine triphosphate (ATP), inorganic phosphate (Pi) and glycerol phosphorylcholine (GPC)) were quantified at all b-values with mean CRLBs below 10%. The ADC values of PCr, ATP, Pi, and GPC were (0.24 ± 0.02, 0.15 ± 0.04, 0.43 ± 0.14, 0.40 ± 0.09) × 10-3 mm2/s, respectively. CONCLUSION The ADCs of four 31P metabolites were successfully measured in the human calf muscle at 7 T, among which those of ATP, Pi and GPC were reported for the first time in humans. This study paves the way to investigate 31P metabolite diffusion properties in health and disease on the clinical MR scanner.
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Affiliation(s)
- Zhiwei Huang
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- CIBM Center for Biomedical Imaging, EPFL CIBM-AIT, Station 6, CH-1015, Lausanne, Switzerland
| | | | - Ying Xiao
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- CIBM Center for Biomedical Imaging, EPFL CIBM-AIT, Station 6, CH-1015, Lausanne, Switzerland
| | - Daniel Wenz
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- CIBM Center for Biomedical Imaging, EPFL CIBM-AIT, Station 6, CH-1015, Lausanne, Switzerland
| | - Lijing Xin
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
- CIBM Center for Biomedical Imaging, EPFL CIBM-AIT, Station 6, CH-1015, Lausanne, Switzerland.
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5
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Dorst J, Borbath T, Ruhm L, Henning A. Phosphorus transversal relaxation times and metabolite concentrations in the human brain at 9.4 T. NMR IN BIOMEDICINE 2022; 35:e4776. [PMID: 35607903 DOI: 10.1002/nbm.4776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/14/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
A method to estimate phosphorus (31 P) transversal relaxation times (T2 s) of coupled spin systems is demonstrated. Additionally, intracellular and extracellular pH and relaxation-corrected metabolite concentrations are reported. Echo time (TE) series of 31 P metabolite spectra were acquired using stimulated echo acquisition mode (STEAM) localization. Spectra were fitted using LCModel with accurately modeled Versatile Simulation, Pulses and Analysis (VeSPA) basis sets accounting for J-evolution of the coupled spin systems. T2 s were estimated by fitting a single exponential two-parameter model across the TE series. Fitted inorganic phosphate frequencies were used to calculate pH, and estimated relaxation times were used to determine the relaxation-corrected brain metabolite concentrations on an assumption of 3 mM γ-ATP. The method was demonstrated in healthy human brain at a field strength of 9.4 T. T2 times of ATP and nicotinamide adenine dinucleotide (NAD) were shortest between 8 and 20 ms, followed by T2 s of inorganic phosphate between 25 and 50 ms, and phosphocreatine with a T2 of 100 ms. Phosphomonoesters and phosphodiesters had the longest T2 s of about 130 ms. The measured T2 s are comparable with literature values and fit in a decreasing trend with increasing field strengths. Calculated pHs and metabolite concentrations are also comparable with literature values.
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Affiliation(s)
- Johanna Dorst
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- International Max Planck Research School for Cognitive and Systems Neuroscience (IMPRS), University of Tübingen, Tübingen, Germany
| | - Tamas Borbath
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Faculty of Science, University of Tübingen, Tübingen, Germany
| | - Loreen Ruhm
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- International Max Planck Research School for Cognitive and Systems Neuroscience (IMPRS), University of Tübingen, Tübingen, Germany
| | - 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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6
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Cameron D, Soto-Mota A, Willis DR, Ellis J, Procter NEK, Greenwood R, Saunders N, Schulte RF, Vassiliou VS, Tyler DJ, Schmid AI, Rodgers CT, Malcolm PN, Clarke K, Frenneaux MP, Valkovič L. Evaluation of Acute Supplementation With the Ketone Ester (R)-3-Hydroxybutyl-(R)-3-Hydroxybutyrate (deltaG) in Healthy Volunteers by Cardiac and Skeletal Muscle 31P Magnetic Resonance Spectroscopy. Front Physiol 2022; 13:793987. [PMID: 35173629 PMCID: PMC8841822 DOI: 10.3389/fphys.2022.793987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/05/2022] [Indexed: 01/11/2023] Open
Abstract
In this acute intervention study, we investigated the potential benefit of ketone supplementation in humans by studying cardiac phosphocreatine to adenosine-triphosphate ratios (PCr/ATP) and skeletal muscle PCr recovery using phosphorus magnetic resonance spectroscopy (31P-MRS) before and after ingestion of a ketone ester drink. We recruited 28 healthy individuals: 12 aged 23–70 years for cardiac 31P-MRS, and 16 aged 60–75 years for skeletal muscle 31P-MRS. Baseline and post-intervention resting cardiac and dynamic skeletal muscle 31P-MRS scans were performed in one visit, where 25 g of the ketone monoester, deltaG®, was administered after the baseline scan. Administration was timed so that post-intervention 31P-MRS would take place 30 min after deltaG® ingestion. The deltaG® ketone drink was well-tolerated by all participants. In participants who provided blood samples, post-intervention blood glucose, lactate and non-esterified fatty acid concentrations decreased significantly (−28.8%, p ≪ 0.001; −28.2%, p = 0.02; and −49.1%, p ≪ 0.001, respectively), while levels of the ketone body D-beta-hydroxybutyrate significantly increased from mean (standard deviation) 0.7 (0.3) to 4.0 (1.1) mmol/L after 30 min (p ≪ 0.001). There were no significant changes in cardiac PCr/ATP or skeletal muscle metabolic parameters between baseline and post-intervention. Acute ketone supplementation caused mild ketosis in blood, with drops in glucose, lactate, and free fatty acids; however, such changes were not associated with changes in 31P-MRS measures in the heart or in skeletal muscle. Future work may focus on the effect of longer-term ketone supplementation on tissue energetics in groups with compromised mitochondrial function.
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Affiliation(s)
- Donnie Cameron
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
- Department of Radiology, C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Leiden, Netherlands
- *Correspondence: Donnie Cameron,
| | - Adrian Soto-Mota
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - David R. Willis
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | - Jane Ellis
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom
| | | | - Richard Greenwood
- Radiology Department, Norfolk and Norwich University Hospital, Norwich, United Kingdom
| | - Neil Saunders
- Radiology Department, Norfolk and Norwich University Hospital, Norwich, United Kingdom
| | | | | | - Damian J. Tyler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom
| | - Albrecht Ingo Schmid
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Christopher T. Rodgers
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom
- Department of Clinical Neurosciences, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Paul N. Malcolm
- Radiology Department, Norfolk and Norwich University Hospital, Norwich, United Kingdom
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Ladislav Valkovič
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom
- Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
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7
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Carrell T, Gu M, Bosshard JC, Sun C, McDougall MP, Wright SM. Assessing the Feasibility of Dynamic 31P Spectroscopy for Metabolic Studies with a 1.0T Extremity Scanner. IEEE Trans Biomed Eng 2021; 69:1975-1982. [PMID: 34855583 DOI: 10.1109/tbme.2021.3132252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Objective: The feasibility of conducting in vivo non-localized 31P Magnetic Resonance Spectroscopy (MRS) with a 1.0T extremity scanner and the potential to increase accessibility of this important diagnostic tool for low cost applications is revisited. Methods: This work presents a custom transmit-only quadrature birdcage, four-element receive coil array, and spectrometer interfaced to a commercial ONI 1.0T magnet for enabling multi-channel, non-1H frequency capabilities. A custom, magnetic resonance compatible plantar flexion-extension exercise device was also developed to enable exercise protocols. The coils were assessed with bench measurements and 31P phantom studies before an in vivo demonstration. Results: In pulse and acquire spectroscopy of a phantom, the array was found to improve the signal-to-noise ratio (SNR) by a factor of 1.31 and reduce the linewidth by 13.9% when compared to a large loop coil of the same overall size. In vivo testing results show that two averages and a four second repetition time for a temporal resolution of eight seconds was sufficient to obtain phosphocreatine recovery values and baseline pH levels aligned with expected literature values. Conclusion: Initial in vivo human skeletal muscle 31P MRS allowed successful monitoring of metabolic changes during an 18-minute exercise protocol. Significance: Adding an array coil and multinuclear capability to a commercial low-cost 1.0T extremity scanner enabled the observation of characteristic 31P metabolic information, such as the phosphocreatine recovery rate and underlying baseline pH.
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Platt T, Ladd ME, Paech D. 7 Tesla and Beyond: Advanced Methods and Clinical Applications in Magnetic Resonance Imaging. Invest Radiol 2021; 56:705-725. [PMID: 34510098 PMCID: PMC8505159 DOI: 10.1097/rli.0000000000000820] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/07/2021] [Accepted: 08/07/2021] [Indexed: 12/15/2022]
Abstract
ABSTRACT Ultrahigh magnetic fields offer significantly higher signal-to-noise ratio, and several magnetic resonance applications additionally benefit from a higher contrast-to-noise ratio, with static magnetic field strengths of B0 ≥ 7 T currently being referred to as ultrahigh fields (UHFs). The advantages of UHF can be used to resolve structures more precisely or to visualize physiological/pathophysiological effects that would be difficult or even impossible to detect at lower field strengths. However, with these advantages also come challenges, such as inhomogeneities applying standard radiofrequency excitation techniques, higher energy deposition in the human body, and enhanced B0 field inhomogeneities. The advantages but also the challenges of UHF as well as promising advanced methodological developments and clinical applications that particularly benefit from UHF are discussed in this review article.
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Affiliation(s)
- Tanja Platt
- From the Medical Physics in Radiology, German Cancer Research Center (DKFZ)
| | - Mark E. Ladd
- From the Medical Physics in Radiology, German Cancer Research Center (DKFZ)
- Faculty of Physics and Astronomy
- Faculty of Medicine, University of Heidelberg, Heidelberg
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg
- Clinic for Neuroradiology, University of Bonn, Bonn, Germany
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9
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Zhang Y, Dahal U, Feng ZV, Rosenzweig Z, Cui Q, Hamers RJ. Influence of Surface Ligand Molecular Structure on Phospholipid Membrane Disruption by Cationic Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7600-7610. [PMID: 34115507 DOI: 10.1021/acs.langmuir.1c01146] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Cationic nanoparticles are known to interact with biological membranes and often cause serious membrane damage. Therefore, it is important to understand the molecular mechanism for such interactions and the factors that impact the degree of membrane damage. Previously, we have demonstrated that spatial distribution of molecular charge at cationic nanoparticle surfaces plays an important role in determining the cellular uptake and membrane damage of these nanoparticles. In this work, using diamond nanoparticles (DNPs) functionalized with five different amine-based surface ligands and small phospholipid unilamellar vesicles (SUVs), we further investigate how chemical features and conformational flexibility of surface ligands impact nanoparticle/membrane interactions. 31P-NMR T2 relaxation measurements quantify the mobility changes in lipid dynamics upon exposing the SUVs to functional DNPs, and coarse-grained molecular dynamics simulations further elucidate molecular details for the different modes of DNP-SUV interactions depending on the surface ligands. Collectively, our results show that the length of the hydrophobic segment and conformational flexibility of surface ligands are two key factors that dictate the degree of membrane damage by the DNP, while the amount of surface charge alone is not predictive of the strength of interaction.
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Affiliation(s)
- Yongqian Zhang
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Udaya Dahal
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Z Vivian Feng
- Chemistry Department, Augsburg University, Minneapolis, Minnesota 55454, United States
| | - Zeev Rosenzweig
- Department of Chemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Robert J Hamers
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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10
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Peeters TH, van Uden MJ, Rijpma A, Scheenen TW, Heerschap A. 3D 31 P MR spectroscopic imaging of the human brain at 3 T with a 31 P receive array: An assessment of 1 H decoupling, T 1 relaxation times, 1 H- 31 P nuclear Overhauser effects and NAD . NMR IN BIOMEDICINE 2021; 34:e4169. [PMID: 31518036 PMCID: PMC8244063 DOI: 10.1002/nbm.4169] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/12/2019] [Accepted: 07/29/2019] [Indexed: 05/02/2023]
Abstract
31 P MR spectroscopic imaging (MRSI) is a versatile technique to study phospholipid precursors and energy metabolism in the healthy and diseased human brain. However, mainly due to its low sensitivity, 31 P MRSI is currently limited to research purposes. To obtain 3D 31 P MRSI spectra with improved signal-to-noise ratio on clinical 3 T MR systems, we used a coil combination consisting of a dual-tuned birdcage transmit coil and a 31 P eight-channel phased-array receive insert. To further increase resolution and sensitivity we applied WALTZ4 1 H decoupling and continuous wave nuclear Overhauser effect (NOE) enhancement and acquired high-quality MRSI spectra with nominal voxel volumes of ~ 17.6 cm3 (effective voxel volume ~ 51 cm3 ) in a clinically relevant measurement time of ~ 13 minutes, without exceeding SAR limits. Steady-state NOE enhancements ranged from 15 ± 9% (γ-ATP) and 33 ± 3% (phosphocreatine) to 48 ± 11% (phosphoethanolamine). Because of these improvements, we resolved and detected all 31 P signals of metabolites that have also been reported for ultrahigh field strengths, including resonances for NAD+ , NADH and extracellular inorganic phosphate. T1 times of extracellular inorganic phosphate were longer than for intracellular inorganic phosphate (3.8 ± 1.4s vs 1.8 ± 0.65 seconds). A comparison of measured T1 relaxation times and NOE enhancements at 3 T with published values between 1.5 and 9.4 T indicates that T1 relaxation of 31 P metabolite spins in the human brain is dominated by dipolar relaxation for this field strength range. Even although intrinsic sensitivity is higher at ultrahigh fields, we demonstrate that at a clinical field strength of 3 T, similar 31 P MRSI information content can be obtained using a sophisticated coil design combined with 1 H decoupling and NOE enhancement.
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Affiliation(s)
- Tom H. Peeters
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Mark J. van Uden
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Anne Rijpma
- Department of Geriatric MedicineRadboud University Medical CenterNijmegenThe Netherlands
- Radboudumc Alzheimer Center, Donders Institute for Brain, Cognition and BehaviourRadboud University Medical CenterNijmegenThe Netherlands
| | - Tom W.J. Scheenen
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
- Erwin L. Hahn InstituteUniversity Hospital Duisburg‐EssenEssenGermany
| | - Arend Heerschap
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
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11
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Mathe Z, McCubbin Stepanic O, Peredkov S, DeBeer S. Phosphorus Kβ X-ray emission spectroscopy detects non-covalent interactions of phosphate biomolecules in situ. Chem Sci 2021; 12:7888-7901. [PMID: 34168842 PMCID: PMC8188515 DOI: 10.1039/d1sc01266e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Phosphorus is ubiquitous in biochemistry, being found in the phosphate groups of nucleic acids and the energy-transferring system of adenine nucleotides (e.g. ATP). Kβ X-ray emission spectroscopy (XES) of phosphorus has been largely unexplored, with no previous applications to biomolecules. Here, the potential of P Kβ XES to study phosphate-containing biomolecules, including ATP and NADPH, is evaluated, as is the application of the technique to aqueous solution samples. P Kβ spectra offer a detailed picture of phosphate valence electronic structure, reporting on subtle non-covalent effects, such as hydrogen bonding and ionic interactions, that are key to enzymatic catalysis. Spectral features are interpreted using density functional theory (DFT) calculations, and potential applications to the study of biological energy conversion are highlighted. Phosphorus X-ray emission spectroscopy probes non-covalent interactions and electronic structure of phosphate biomolecules in both solid and solution samples.![]()
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Affiliation(s)
- Zachary Mathe
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Olivia McCubbin Stepanic
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Sergey Peredkov
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34-36 D-45470 Mülheim an der Ruhr Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34-36 D-45470 Mülheim an der Ruhr Germany
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12
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Mandić M, Forsgren MF, Romu T, Widholm P, Sundblad P, Gustafsson T, Rullman E. Interval-induced metabolic perturbation determines tissue fluid shifts into skeletal muscle. Physiol Rep 2021; 9:e14841. [PMID: 33904652 PMCID: PMC8077120 DOI: 10.14814/phy2.14841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/26/2021] [Accepted: 03/08/2021] [Indexed: 12/23/2022] Open
Abstract
Intense interval exercise has proven to be as effective as traditional endurance exercise in improving maximal oxygen uptake. Shared by these two exercise regimes is an acute reduction in plasma volume, which is a suggested stimulus behind exercise-induced increases in blood volume and maximal oxygen uptake. This study aimed to link exercise-induced metabolic perturbation with volume shifts into skeletal muscle tissue. Ten healthy subjects (mean age 33 ± 8 years, 5 males and 5 females) performed three 30 s all-out sprints on a cycle ergometer. Upon cessation of exercise magnetic resonance imaging, 31 Phosphorus magnetic resonance spectroscopy and blood samples were used to measure changes in muscle volume, intramuscular energy metabolites and plasma volume. Compared to pre-exercise, muscle volume increased from 1147.1 ± 35.6 ml to 1283.3 ± 11.0 ml 8 min post-exercise. At 30 min post-exercise, muscle volume was still higher than pre-exercise (1147.1 ± 35.6 vs. 1222.2 ± 6.8 ml). Plasma volume decreased by 16 ± 3% immediately post-exercise and recovered back to - 5 ± 6% after 30 min. Principal component analysis of exercise performance, muscle and plasma volume changes as well as changes in intramuscular energy metabolites showed generally strong correlations between metabolic and physiological variables. The strongest predictor for the volume shifts of muscle and plasma was the magnitude of glucose-6-phosphate accumulation post-exercise. Interval training leads to large metabolic and hemodynamic perturbations with accumulation of glucose-6-phosphate as a possible key event in the fluid flux between the vascular compartment and muscle tissue.
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Affiliation(s)
- Mirko Mandić
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Mikael F Forsgren
- AMRA Medical AB, Linköping, Sweden.,Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | | | - Per Widholm
- AMRA Medical AB, Linköping, Sweden.,Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Department of Radiology, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Patrik Sundblad
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Gustafsson
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Eric Rullman
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
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13
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Sassani M, Alix JJ, McDermott CJ, Baster K, Hoggard N, Wild JM, Mortiboys HJ, Shaw PJ, Wilkinson ID, Jenkins TM. Magnetic resonance spectroscopy reveals mitochondrial dysfunction in amyotrophic lateral sclerosis. Brain 2021; 143:3603-3618. [PMID: 33439988 DOI: 10.1093/brain/awaa340] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/16/2020] [Accepted: 08/08/2020] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial dysfunction is postulated to be central to amyotrophic lateral sclerosis (ALS) pathophysiology. Evidence comes primarily from disease models and conclusive data to support bioenergetic dysfunction in vivo in patients is currently lacking. This study is the first to assess mitochondrial dysfunction in brain and muscle in individuals living with ALS using 31P-magnetic resonance spectroscopy (MRS), the modality of choice to assess energy metabolism in vivo. We recruited 20 patients and 10 healthy age and gender-matched control subjects in this cross-sectional clinico-radiological study. 31P-MRS was acquired from cerebral motor regions and from tibialis anterior during rest and exercise. Bioenergetic parameter estimates were derived including: ATP, phosphocreatine, inorganic phosphate, adenosine diphosphate, Gibbs free energy of ATP hydrolysis (ΔGATP), phosphomonoesters, phosphodiesters, pH, free magnesium concentration, and muscle dynamic recovery constants. Linear regression was used to test for associations between brain data and clinical parameters (revised amyotrophic functional rating scale, slow vital capacity, and upper motor neuron score) and between muscle data and clinico-neurophysiological measures (motor unit number and size indices, force of contraction, and speed of walking). Evidence for primary dysfunction of mitochondrial oxidative phosphorylation was detected in the brainstem where ΔGATP and phosphocreatine were reduced. Alterations were also detected in skeletal muscle in patients where resting inorganic phosphate, pH, and phosphomonoesters were increased, whereas resting ΔGATP, magnesium, and dynamic phosphocreatine to inorganic phosphate recovery were decreased. Phosphocreatine in brainstem correlated with respiratory dysfunction and disability; in muscle, energy metabolites correlated with motor unit number index, muscle power, and speed of walking. This study provides in vivo evidence for bioenergetic dysfunction in ALS in brain and skeletal muscle, which appears clinically and electrophysiologically relevant. 31P-MRS represents a promising technique to assess the pathophysiology of mitochondrial function in vivo in ALS and a potential tool for future clinical trials targeting bioenergetic dysfunction.
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Affiliation(s)
- Matilde Sassani
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - James J Alix
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Christopher J McDermott
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Kathleen Baster
- Statistical Service Unit, University of Sheffield, Sheffield, UK
| | - Nigel Hoggard
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Jim M Wild
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Heather J Mortiboys
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Iain D Wilkinson
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Thomas M Jenkins
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
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14
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Froeling M, Prompers JJ, Klomp DWJ, van der Velden TA. PCA denoising and Wiener deconvolution of 31 P 3D CSI data to enhance effective SNR and improve point spread function. Magn Reson Med 2021; 85:2992-3009. [PMID: 33522635 PMCID: PMC7986807 DOI: 10.1002/mrm.28654] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/10/2020] [Accepted: 12/01/2020] [Indexed: 12/19/2022]
Abstract
Purpose This study evaluates the performance of 2 processing methods, that is, principal component analysis‐based denoising and Wiener deconvolution, to enhance the quality of phosphorus 3D chemical shift imaging data. Methods Principal component analysis‐based denoising increases the SNR while maintaining spectral information. Wiener deconvolution reduces the FWHM of the voxel point spread function, which is increased by Hamming filtering or Hamming‐weighted acquisition. The proposed methods are evaluated using simulated and in vivo 3D phosphorus chemical shift imaging data by 1) visual inspection of the spatial signal distribution; 2) SNR calculation of the PCr peak; and 3) fitting of metabolite basis functions. Results With the optimal order of processing steps, we show that the effective SNR of in vivo phosphorus 3D chemical shift imaging data can be increased. In simulations, we show we can preserve phosphorus‐containing metabolite peaks that had an SNR < 1 before denoising. Furthermore, using Wiener deconvolution, we were able to reduce the FWHM of the voxel point spread function with only partially reintroducing Gibb‐ringing artifacts while maintaining the SNR. After data processing, fitting of the phosphorus‐containing metabolite signals improved. Conclusion In this study, we have shown that principal component analysis‐based denoising in combination with regularized Wiener deconvolution allows increasing the effective spectral SNR of in vivo phosphorus 3D chemical shift imaging data, with reduction of the FWHM of the voxel point spread function. Processing increased the effective SNR by at least threefold compared to Hamming weighted acquired data and minimized voxel bleeding. With these methods, fitting of metabolite amplitudes became more robust with decreased fitting residuals.
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Affiliation(s)
- Martijn Froeling
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tijl A van der Velden
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
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15
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Abstract
Regulatory approval of ultrahigh field (UHF) MR imaging scanners for clinical use has opened new opportunities for musculoskeletal imaging applications. UHF MR imaging has unique advantages in terms of signal-to-noise ratio, contrast-to-noise ratio, spectral resolution, and multinuclear applications, thus providing unique information not available at lower field strengths. But UHF also comes with a set of technical challenges that are yet to be resolved and may not be suitable for all imaging applications. This review focuses on the latest research in musculoskeletal MR imaging applications at UHF including morphologic imaging, T2, T2∗, and T1ρ mapping, chemical exchange saturation transfer, sodium imaging, and phosphorus spectroscopy imaging applications.
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16
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Hooijmans MT, Froeling M, Koeks Z, Verschuuren JJ, Webb A, Niks EH, Kan HE. Multi-parametric MR in Becker muscular dystrophy patients. NMR IN BIOMEDICINE 2020; 33:e4385. [PMID: 32754921 PMCID: PMC7687231 DOI: 10.1002/nbm.4385] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 05/14/2023]
Abstract
Quantitative MRI and MRS of muscle are increasingly being used to measure individual pathophysiological processes in Becker muscular dystrophy (BMD). In particular, muscle fat fraction was shown to be highly associated with functional tests in BMD. However, the muscle strength per unit of contractile cross-sectional area is lower in patients with BMD compared with healthy controls. This suggests that the quality of the non-fat-replaced (NFR) muscle tissue is lower than in healthy controls. Consequently, a measure that reflects changes in muscle tissue itself is needed. Here, we explore the potential of water T2 relaxation times, diffusion parameters and phosphorus metabolic indices as early disease markers in patients with BMD. For this purpose, we examined these measures in fat-replaced (FR) and NFR lower leg muscles in patients with BMD and compared these values with those in healthy controls. Quantitative proton MRI (three-point Dixon, multi-spin-echo and diffusion-weighted spin-echo echo planar imaging) and 2D chemical shift imaging 31 P MRS data were acquired in 24 patients with BMD (age 18.8-66.2 years) and 13 healthy controls (age 21.3-63.6 years). Muscle fat fractions, phosphorus metabolic indices, and averages and standard deviations (SDs) of the water T2 relaxation times and diffusion tensor imaging (DTI) parameters were assessed in six individual leg muscles. Phosphodiester levels were increased in the NFR and FR tibialis anterior, FR peroneus and FR gastrocnemius lateralis muscles. No clear pattern was visible for the other metabolic indices. Increased T2 SD was found in the majority of FR muscles compared with NFR and healthy control muscles. No differences in average water T2 relaxation times or DTI indices were found between groups. Overall, our results indicate that primarily muscles that are further along in the disease process showed increases in T2 heterogeneity and changes in some metabolic indices. No clear differences were found for the DTI indices between groups.
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Affiliation(s)
- Melissa T. Hooijmans
- C.J. Gorter Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Department of Biomedical Engineering & PhysicsAmsterdam University Medical CentersAmsterdamThe Netherlands
| | - Martijn Froeling
- Department of RadiologyUtrecht University Medical CenterUtrechtThe Netherlands
| | - Zaida Koeks
- Department of NeurologyLeiden University Medical CenterLeidenThe Netherlands
| | - Jan J.G.M. Verschuuren
- Department of NeurologyLeiden University Medical CenterLeidenThe Netherlands
- Duchenne Center NetherlandsThe Netherlands
| | - Andrew Webb
- C.J. Gorter Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Erik H. Niks
- Department of NeurologyLeiden University Medical CenterLeidenThe Netherlands
- Duchenne Center NetherlandsThe Netherlands
| | - Hermien E. Kan
- C.J. Gorter Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Duchenne Center NetherlandsThe Netherlands
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17
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Evidence of Mitochondrial Dysfunction in Fibromyalgia: Deviating Muscle Energy Metabolism Detected Using Microdialysis and Magnetic Resonance. J Clin Med 2020; 9:jcm9113527. [PMID: 33142767 PMCID: PMC7693920 DOI: 10.3390/jcm9113527] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 12/14/2022] Open
Abstract
In fibromyalgia (FM) muscle metabolism, studies are sparse and conflicting associations have been found between muscle metabolism and pain aspects. This study compared alterations in metabolic substances and blood flow in erector spinae and trapezius of FM patients and healthy controls. FM patients (n = 33) and healthy controls (n = 31) underwent a clinical examination that included pressure pain thresholds and physical tests, completion of a health questionnaire, participation in microdialysis investigations of the etrapezius and erector spinae muscles, and also underwent phosphorus-31 magnetic resonance spectroscopy of the erector spinae muscle. At the baseline, FM had significantly higher levels of pyruvate in both muscles. Significantly lower concentrations of phosphocreatine (PCr) and nucleotide triphosphate (mainly adenosine triphosphate) in erector spinae were found in FM. Blood flow in erector spinae was significantly lower in FM. Significant associations between metabolic variables and pain aspects (pain intensity and pressure pain threshold PPT) were found in FM. Our results suggest that FM has mitochondrial dysfunction, although it is unclear whether inactivity, obesity, aging, and pain are causes of, the results of, or coincidental to the mitochondrial dysfunction. The significant regressions of pain intensity and PPT in FM agree with other studies reporting associations between peripheral biological factors and pain aspects.
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18
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Valkovič L, Lau JYC, Abdesselam I, Rider OJ, Frollo I, Tyler DJ, Rodgers CT, Miller JJJ. Effects of contrast agents on relaxation properties of 31P metabolites. Magn Reson Med 2020; 85:1805-1813. [PMID: 33090502 DOI: 10.1002/mrm.28541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/22/2020] [Accepted: 09/14/2020] [Indexed: 11/10/2022]
Abstract
PURPOSE Phosphorous MR spectroscopy (31P-MRS) forms a powerful, non-invasive research tool to quantify the energetics of the heart in diverse patient populations. 31P-MRS is frequently applied alongside other radiological examinations, many of which use various contrast agents that shorten relaxation times of water in conventional proton MR, for a better characterisation of cardiac function, or following prior computed tomography (CT). It is, however, unknown whether these agents confound 31P-MRS signals, for example, 2,3-diphosphoglycerate (2,3-DPG). METHODS In this work, we quantitatively assess the impact of non-ionic, low osmolar iodinated CT contrast agent (iopamidol/Niopam), gadolinium chelates (linear gadopentetic acid dimeglumine/Magnevist and macrocyclic gadoterate meglumine/Dotarem) and superparamagnetic iron oxide nanoparticles (ferumoxytol/Feraheme) on the nuclear T1 and T2 of 31P metabolites (ie, 2,3-DPG), and 1H in water in live human blood and saline phantoms at 11.7 T. RESULTS Addition of all contrast agents led to significant shortening of all relaxation times in both 1H and 31P saline phantoms. On the contrary, the T1 relaxation time of 2,3-DPG in blood was significantly shortened only by Magnevist (P = .03). Similarly, the only contrast agent that influenced the T2 relaxation times of 2,3-DPG in blood samples was ferumoxytol (P = .02). CONCLUSION Our results show that, unlike conventional proton MR, phosphorus MRS is unconfounded in patients who have had prior CT with contrast, not all gadolinium-based contrast agents influence 31P-MRS data in vivo, and that ferumoxytol is a promising contrast agent for the reduction in 31P-MRS blood-pool signal.
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Affiliation(s)
- Ladislav Valkovič
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
- Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Justin Y C Lau
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Ines Abdesselam
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Oliver J Rider
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Ivan Frollo
- Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Damian J Tyler
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Christopher T Rodgers
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
- The Wolfson Brain Imaging Centre, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Jack J J Miller
- Oxford Centre for Clinical MR Research (OCMR), RDM Cardiovascular Medicine, University of Oxford, Oxford, UK
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
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19
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Apps A, Valkovič L, Peterzan M, Lau JYC, Hundertmark M, Clarke W, Tunnicliffe EM, Ellis J, Tyler DJ, Neubauer S, Rider OJ, Rodgers CT, Schmid AI. Quantifying the effect of dobutamine stress on myocardial Pi and pH in healthy volunteers: A 31 P MRS study at 7T. Magn Reson Med 2020; 85:1147-1159. [PMID: 32929770 PMCID: PMC8239988 DOI: 10.1002/mrm.28494] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 07/07/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022]
Abstract
Purpose Phosphorus spectroscopy (31P‐MRS) is a proven method to probe cardiac energetics. Studies typically report the phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. We focus on another 31P signal: inorganic phosphate (Pi), whose chemical shift allows computation of myocardial pH, with Pi/PCr providing additional insight into cardiac energetics. Pi is often obscured by signals from blood 2,3‐diphosphoglycerate (2,3‐DPG). We introduce a method to quantify Pi in 14 min without hindrance from 2,3‐DPG. Methods Using a 31P stimulated echo acquisition mode (STEAM) sequence at 7 Tesla that inherently suppresses signal from 2,3‐DPG, the Pi peak was cleanly resolved. Resting state UTE‐chemical shift imaging (PCr/ATP) and STEAM 31P‐MRS (Pi/PCr, pH) were undertaken in 23 healthy controls; pH and Pi/PCr were subsequently recorded during dobutamine infusion. Results We achieved a clean Pi signal both at rest and stress with good 2,3‐DPG suppression. Repeatability coefficient (8 subjects) for Pi/PCr was 0.036 and 0.12 for pH. We report myocardial Pi/PCr and pH at rest and during catecholamine stress in healthy controls. Pi/PCr was maintained during stress (0.098 ± 0.031 [rest] vs. 0.098 ± 0.031 [stress] P = .95); similarly, pH did not change (7.09 ± 0.07 [rest] vs. 7.08 ± 0.11 [stress] P = .81). Feasibility for patient studies was subsequently successfully demonstrated in a patient with cardiomyopathy. Conclusion We introduced a method that can resolve Pi using 7 Tesla STEAM 31P‐MRS. We demonstrate the stability of Pi/PCr and myocardial pH in volunteers at rest and during catecholamine stress. This protocol is feasible in patients and potentially of use for studying pathological myocardial energetics.
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Affiliation(s)
- Andrew Apps
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Mark Peterzan
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Justin Y C Lau
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Moritz Hundertmark
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - William Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Elizabeth M Tunnicliffe
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jane Ellis
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Damian J Tyler
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Oliver J Rider
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Christopher T Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom
| | - Albrecht Ingo Schmid
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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20
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Santos-Díaz A, Noseworthy MD. Phosphorus magnetic resonance spectroscopy and imaging (31P-MRS/MRSI) as a window to brain and muscle metabolism: A review of the methods. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.101967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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21
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Krumpolec P, Klepochová R, Just I, Tušek Jelenc M, Frollo I, Ukropec J, Ukropcová B, Trattnig S, Krššák M, Valkovič L. Multinuclear MRS at 7T Uncovers Exercise Driven Differences in Skeletal Muscle Energy Metabolism Between Young and Seniors. Front Physiol 2020; 11:644. [PMID: 32695010 PMCID: PMC7336536 DOI: 10.3389/fphys.2020.00644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 05/20/2020] [Indexed: 12/27/2022] Open
Abstract
Purpose: Aging is associated with changes in muscle energy metabolism. Proton (1H) and phosphorous (31P) magnetic resonance spectroscopy (MRS) has been successfully applied for non-invasive investigation of skeletal muscle metabolism. The aim of this study was to detect differences in adenosine triphosphate (ATP) production in the aging muscle by 31P-MRS and to identify potential changes associated with buffer capacity of muscle carnosine by 1H-MRS. Methods: Fifteen young and nineteen elderly volunteers were examined. 1H and 31P-MRS spectra were acquired at high field (7T). The investigation included carnosine quantification using 1H-MRS and resting and dynamic 31P-MRS, both including saturation transfer measurements of phosphocreatine (PCr), and inorganic phosphate (Pi)-to-ATP metabolic fluxes. Results: Elderly volunteers had higher time constant of PCr recovery (τPCr) in comparison to the young volunteers. Exercise was connected with significant decrease in PCr-to-ATP flux in both groups. Moreover, PCr-to-ATP flux was significantly higher in young compared to elderly both at rest and during exercise. Similarly, an increment of Pi-to-ATP flux with exercise was found in both groups but the intergroup difference was only observed during exercise. Elderly had lower muscle carnosine concentration and lower postexercise pH. A strong increase in phosphomonoester (PME) concentration was observed with exercise in elderly, and a faster Pi:PCr kinetics was found in young volunteers compared to elderly during the recovery period. Conclusion: Observations of a massive increment of PME concentration together with high Pi-to-ATP flux during exercise in seniors refer to decreased ability of the muscle to meet the metabolic requirements of exercise and thus a limited ability of seniors to effectively support the exercise load.
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Affiliation(s)
- Patrik Krumpolec
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Biomedical Research Center, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Radka Klepochová
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ivica Just
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Marjeta Tušek Jelenc
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ivan Frollo
- Department of Imaging Methods, Institute of Measurements Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jozef Ukropec
- Biomedical Research Center, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Barbara Ukropcová
- Biomedical Research Center, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia.,Faculty of Medicine, Institute of Pathophysiology, Comenius University in Bratislava, Bratislava, Slovakia
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Martin Krššák
- High Field MR Center, 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
| | - Ladislav Valkovič
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Department of Imaging Methods, Institute of Measurements Science, Slovak Academy of Sciences, Bratislava, Slovakia.,Oxford Centre for Clinical Magnetic Resonance Research, RDM Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
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22
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Meyerspeer M, Boesch C, Cameron D, Dezortová M, Forbes SC, Heerschap A, Jeneson JA, Kan HE, Kent J, Layec G, Prompers JJ, Reyngoudt H, Sleigh A, Valkovič L, Kemp GJ. 31 P magnetic resonance spectroscopy in skeletal muscle: Experts' consensus recommendations. NMR IN BIOMEDICINE 2020; 34:e4246. [PMID: 32037688 PMCID: PMC8243949 DOI: 10.1002/nbm.4246] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 12/01/2019] [Accepted: 12/02/2019] [Indexed: 05/07/2023]
Abstract
Skeletal muscle phosphorus-31 31 P MRS is the oldest MRS methodology to be applied to in vivo metabolic research. The technical requirements of 31 P MRS in skeletal muscle depend on the research question, and to assess those questions requires understanding both the relevant muscle physiology, and how 31 P MRS methods can probe it. Here we consider basic signal-acquisition parameters related to radio frequency excitation, TR, TE, spectral resolution, shim and localisation. We make specific recommendations for studies of resting and exercising muscle, including magnetisation transfer, and for data processing. We summarise the metabolic information that can be quantitatively assessed with 31 P MRS, either measured directly or derived by calculations that depend on particular metabolic models, and we give advice on potential problems of interpretation. We give expected values and tolerable ranges for some measured quantities, and minimum requirements for reporting acquisition parameters and experimental results in publications. Reliable examination depends on a reproducible setup, standardised preconditioning of the subject, and careful control of potential difficulties, and we summarise some important considerations and potential confounders. Our recommendations include the quantification and standardisation of contraction intensity, and how best to account for heterogeneous muscle recruitment. We highlight some pitfalls in the assessment of mitochondrial function by analysis of phosphocreatine (PCr) recovery kinetics. Finally, we outline how complementary techniques (near-infrared spectroscopy, arterial spin labelling, BOLD and various other MRI and 1 H MRS measurements) can help in the physiological/metabolic interpretation of 31 P MRS studies by providing information about blood flow and oxygen delivery/utilisation. Our recommendations will assist in achieving the fullest possible reliable picture of muscle physiology and pathophysiology.
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Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- High Field MR CenterMedical University of ViennaViennaAustria
| | - Chris Boesch
- DBMR and DIPRUniversity and InselspitalBernSwitzerland
| | - Donnie Cameron
- Norwich Medical SchoolUniversity of East AngliaNorwichUK
- C. J. Gorter Center for High Field MRI, Department of RadiologyLeiden University Medical CentreLeidenthe Netherlands
| | - Monika Dezortová
- MR‐Unit, Department of Diagnostic and Interventional RadiologyInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Sean C. Forbes
- Department of Physical TherapyUniversity of FloridaGainesvilleFloridaUSA
| | - Arend Heerschap
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Jeroen A.L. Jeneson
- Department of RadiologyAmsterdam University Medical Center|site AMCAmsterdamthe Netherlands
- Cognitive Neuroscience CenterUniversity Medical Center GroningenGroningenthe Netherlands
- Center for Child Development and Exercise, Wilhelmina Children's HospitalUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Hermien E. Kan
- C. J. Gorter Center for High Field MRI, Department of RadiologyLeiden University Medical CentreLeidenthe Netherlands
- Duchenne CenterThe Netherlands
| | - Jane Kent
- Department of KinesiologyUniversity of Massachusetts AmherstMAUSA
| | - Gwenaël Layec
- Department of KinesiologyUniversity of Massachusetts AmherstMAUSA
- Institute for Applied Life SciencesUniversity of MassachusettsAmherstMAUSA
| | | | - Harmen Reyngoudt
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of Myology AIM‐CEAParisFrance
| | - Alison Sleigh
- Wolfson Brain Imaging CentreUniversity of CambridgeCambridgeUK
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
- NIHR/Wellcome Trust Clinical Research FacilityCambridge University Hospitals NHS Foundation TrustCambridgeUK
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), RDM Cardiovascular Medicine, BHF Centre of Research ExcellenceUniversity of OxfordOxfordUK
- Department of Imaging MethodsInstitute of Measurement Science, Slovak Academy of SciencesBratislavaSlovakia
| | - Graham J. Kemp
- Department of Musculoskeletal Biology and Liverpool Magnetic Resonance Imaging Centre (LiMRIC)University of LiverpoolLiverpoolUK
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23
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Carrell T, Gu M, McDougall MP, Wright SM. Feasibility of Using a 1T Extremity Scanner with a Four-Element Array to Detect 31P in the Human Calf. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:6806-6809. [PMID: 31947403 DOI: 10.1109/embc.2019.8857122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The feasibility of conducting in vivo non-localized skeletal muscle 31P Magnetic Resonance Spectroscopy (MRS) with a low-cost extremity 1 Tesla magnet is demonstrated. We designed and built a transmit-only quadrature birdcage, four-element receive coil array, and employed a home-built spectrometer interfaced with a commercial ONI 1.0T magnet. In phantom comparison tests with a large loop coil of comparable size, the array was found to improve the SNR by a factor of 1.8 and the linewidth from 0.72 ppm to 0.45 ppm. Phantom and in vivo testing results show only 6 averages with a 4 second repetition time are required to obtain quantifiable 31P spectra. Initial in vivo human skeletal muscle 31P spectra successfully allowed for peak characterization. A low-cost approach to MRS could enable more widespread use of this tool in clinical diagnosis and in vivo metabolic research.
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24
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van Houtum Q, Welting D, Gosselink W, Klomp D, Arteaga de Castro C, van der Kemp W. Low SAR 31 P (multi-echo) spectroscopic imaging using an integrated whole-body transmit coil at 7T. NMR IN BIOMEDICINE 2019; 32:e4178. [PMID: 31608515 PMCID: PMC6900186 DOI: 10.1002/nbm.4178] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/06/2019] [Accepted: 08/15/2019] [Indexed: 05/10/2023]
Abstract
Phosphorus (31 P) MRSI provides opportunities to monitor potential biomarkers. However, current applications of 31 P MRS are generally restricted to relatively small volumes as small coils are used. Conventional surface coils require high energy adiabatic RF pulses to achieve flip angle homogeneity, leading to high specific absorption rates (SARs), and occupy space within the MRI bore. A birdcage coil behind the bore cover can potentially reduce the SAR constraints massively by use of conventional amplitude modulated pulses without sacrificing patient space. Here, we demonstrate that the integrated 31 P birdcage coil setup with a high power RF amplifier at 7 T allows for low flip angle excitations with short repetition time (TR ) for fast 3D chemical shift imaging (CSI) and 3D T1 -weighted CSI as well as high flip angle multi-refocusing pulses, enabling multi-echo CSI that can measure metabolite T2 , over a large field of view in the body. B1+ calibration showed a variation of only 30% in maximum B1 in four volunteers. High signal-to-noise ratio (SNR) MRSI was obtained in the gluteal muscle using two fast in vivo 3D spectroscopic imaging protocols, with low and high flip angles, and with multi-echo MRSI without exceeding SAR levels. In addition, full liver MRSI was achieved within SAR constraints. The integrated 31 P body coil allowed for fast spectroscopic imaging and successful implementation of the multi-echo method in the body at 7 T. Moreover, no additional enclosing hardware was needed for 31 P excitation, paving the way to include larger subjects and more space for receiver arrays. The increase in possible number of RF excitations per scan time, due to the improved B1+ homogeneity and low SAR, allows SNR to be exchanged for spatial resolution in CSI and/or T1 weighting by simply manipulating TR and/or flip angle to detect and quantify ratios from different molecular species.
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Affiliation(s)
- Q. van Houtum
- University Medical Center UtrechtUtrechtThe Netherlands
| | - D. Welting
- University Medical Center UtrechtUtrechtThe Netherlands
| | | | - D.W.J. Klomp
- University Medical Center UtrechtUtrechtThe Netherlands
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25
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Demberg K, Laun FB, Bachert P, Ladd ME, Kuder TA. Stimulated echo double diffusion encoded imaging of closed pores: Influence and removal of unbalanced terms. Phys Rev E 2019; 100:042408. [PMID: 31770958 DOI: 10.1103/physreve.100.042408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Indexed: 11/07/2022]
Abstract
Nuclear magnetic resonance (NMR) diffusion pore imaging has been proposed to study the shape of arbitrary closed pores filled with an NMR-detectable medium by use of nonclassical diffusion encoding schemes. Potential applications can be found in biomedical imaging and porous media research. When studying non-point-symmetric pores, NMR signals with nonvanishing imaginary parts arise containing the pore shape information, which is lost for classical diffusion encoding schemes. Key limitations are the required high magnetic field gradient amplitudes and T2 relaxation while approaching the diffusion long-time limit. To benefit from the slower T1 decay, we demonstrate the feasibility of diffusion pore imaging with stimulated echoes using Monte Carlo simulations and experiments with hyperpolarized xenon-129 gas in well-defined geometries and show that the necessary complex-valued signals can be acquired. Analytical derivation of the stimulated echo double diffusion encoded signal was performed to investigate the effect of the additionally arising undesired terms on the complex phase information. These terms correspond to signals arising for spin-echo sequences with unbalanced gradients. For most possible applications, the unbalanced terms can be neglected. If non-negligible, selection of the appropriate signal component using a phase cycling scheme was demonstrated experimentally. Using stimulated echoes may be a step towards application of diffusion pore imaging to larger pores with gradient amplitudes available today in preclinical systems.
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Affiliation(s)
- Kerstin Demberg
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Frederik Bernd Laun
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Mark Edward Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.,Faculty of Medicine, Heidelberg University, Heidelberg, Germany
| | - Tristan Anselm Kuder
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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26
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van der Kemp WJ, van der Velden TA, Schmitz AM, Gilhuijs KG, Luijten PR, Klomp DW, Wijnen JP. Shortening of apparent transverse relaxation time of inorganic phosphate as a breast cancer biomarker. NMR IN BIOMEDICINE 2019; 32:e4011. [PMID: 30311703 PMCID: PMC6899594 DOI: 10.1002/nbm.4011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 05/11/2023]
Abstract
Phosphorus MRS offers a non-invasive tool for monitoring cell energy and phospholipid metabolism and can be of additional value in diagnosing cancer and monitoring cancer therapy. In this study, we determined the transverse relaxation times of a number of phosphorous metabolites in a group of breast cancer patients by adiabatic multi-echo spectroscopic imaging at 7 T. The transverse relaxation times of phosphoethanolamine, phosphocholine, inorganic phosphate (Pi ), glycerophosphocholine and glycerophosphatidylcholine were 184 ± 8 ms, 203 ± 17 ms, 87 ± 8 ms, 240 ± 56 ms and 20 ± 10 ms, respectively. The transverse relaxation time of Pi in breast cancer tissue was less than half that of healthy fibroglandular tissue. This effect is most likely caused by an up-regulation of glycolysis in breast cancer tissue that leads to interaction of Pi with the GAPDH enzyme, which forms part of the reversible pathway of exchange of Pi with gamma-adenosine tri-phosphate, thus shortening its apparent transverse relaxation time. As healthy breast tissue shows very little glycolytic activity, the apparent T2 shortening of Pi due to malignant transformation could possibly be used as a biomarker for cancer.
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Affiliation(s)
| | | | | | - Kenneth G. Gilhuijs
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Peter R. Luijten
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Dennis W.J. Klomp
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Jannie P. Wijnen
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
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27
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Valkovič L, Clarke WT, Schmid AI, Raman B, Ellis J, Watkins H, Robson MD, Neubauer S, Rodgers CT. Measuring inorganic phosphate and intracellular pH in the healthy and hypertrophic cardiomyopathy hearts by in vivo 7T 31P-cardiovascular magnetic resonance spectroscopy. J Cardiovasc Magn Reson 2019; 21:19. [PMID: 30871562 PMCID: PMC6419336 DOI: 10.1186/s12968-019-0529-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 02/14/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Cardiovascular phosphorus MR spectroscopy (31P-CMRS) is a powerful tool for probing energetics in the human heart, through quantification of phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. In principle, 31P-CMRS can also measure cardiac intracellular pH (pHi) and the free energy of ATP hydrolysis (ΔGATP). However, these require determination of the inorganic phosphate (Pi) signal frequency and amplitude that are currently not robustly accessible because blood signals often obscure the Pi resonance. Typical cardiac 31P-CMRS protocols use low (e.g. 30°) flip-angles and short repetition time (TR) to maximise signal-to-noise ratio (SNR) within hardware limits. Unfortunately, this causes saturation of Pi with negligible saturation of the flowing blood pool. We aimed to show that an adiabatic 90° excitation, long-TR, 7T 31P-CMRS protocol will reverse this balance, allowing robust cardiac pHi measurements in healthy subjects and patients with hypertrophic cardiomyopathy (HCM). METHODS The cardiac Pi T1 was first measured by the dual TR technique in seven healthy subjects. Next, ten healthy subjects and three HCM patients were scanned with 7T 31P-MRS using long (6 s) TR protocol and adiabatic excitation. Spectra were fitted for cardiac metabolites including Pi. RESULTS The measured Pi T1 was 5.0 ± 0.3 s in myocardium and 6.4 ± 0.6 s in skeletal muscle. Myocardial pH was 7.12 ± 0.04 and Pi/PCr ratio was 0.11 ± 0.02. The coefficients of repeatability were 0.052 for pH and 0.027 for Pi/PCr quantification. The pH in HCM patients did not differ (p = 0.508) from volunteers. However, Pi/PCr was higher (0.24 ± 0.09 vs. 0.11 ± 0.02; p = 0.001); Pi/ATP was higher (0.44 ± 0.14 vs. 0.24 ± 0.05; p = 0.002); and PCr/ATP was lower (1.78 ± 0.07 vs. 2.10 ± 0.20; p = 0.020), in HCM patients, which is in agreement with previous reports. CONCLUSION A 7T 31P-CMRS protocol with adiabatic 90° excitation and long (6 s) TR gives sufficient SNR for Pi and low enough blood signal to permit robust quantification of cardiac Pi and hence pHi. Pi was detectable in every subject scanned for this study, both in healthy subjects and HCM patients. Cardiac pHi was unchanged in HCM patients, but both Pi/PCr and Pi/ATP increased that indicate an energetic impairment in HCM. This work provides a robust technique to quantify cardiac Pi and pHi.
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Affiliation(s)
- Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
- Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - William T. Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Albrecht I. Schmid
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
- High-Field MR Centre, Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Betty Raman
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Jane Ellis
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Hugh Watkins
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Division of Cardiovascular Medicine, BHF Centre of Research Excellence, University of Oxford, Oxford, UK
- The Wolfson Brain Imaging Centre, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
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28
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Ren J, Sherry AD, Malloy CR. Modular 31 P wideband inversion transfer for integrative analysis of adenosine triphosphate metabolism, T 1 relaxation and molecular dynamics in skeletal muscle at 7T. Magn Reson Med 2019; 81:3440-3452. [PMID: 30793793 DOI: 10.1002/mrm.27686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 12/13/2022]
Abstract
PURPOSE For efficient and integrative analysis of de novo adenosine triphosphate (ATP) synthesis, creatine-kinase-mediated ATP synthesis, T1 relaxation time, and ATP molecular motion dynamics in human skeletal muscle at rest. METHODS Four inversion-transfer modules differing in center inversion frequency were combined to generate amplified magnetization transfer (MT) effects in targeted MT pathways, including Pi ↔ γ-ATP, PCr ↔ γ-ATP, and 31 Pγ(α)ATP ↔ 31 PβATP . MT effects from both forward and reverse exchange kinetic pathways were acquired to reduce potential bias and confounding factors in integrated data analysis. RESULTS Kinetic data collected using 4 wideband inversion modules (8 minutes each) yielded the forward exchange rate constants, kPCr →γ ATP = 0.31 ± 0.05 s-1 and kPi →γ ATP = 0.064 ± 0.012 s-1 , and the reverse exchange rate constants, kγATP→Pi = 0.034 ± 0.006 s-1 and kγATP→PCr = 1.37 ± 0.22 s-1 , respectively. The cross-relaxation rate constant, σγ(α) ↔ βATP was -0.20 ± 0.03 s-1 , corresponding to ATP rotational correlation time τc of 0.8 ± 0.1 × 10-7 seconds. The intrinsic T1 relaxation times were Pi (9.2 ± 1.4 seconds), PCr (6.2 ± 0.4 seconds), γ-ATP (1.8 ± 0.1 seconds), α-ATP (1.4 ± 0.1 seconds), and β-ATP (1.1 ± 0.1 seconds). Muscle ATP T1 values were found to be significantly longer than those previously measured in the brain using a similar method. CONCLUSION A combination of multiple inversion transfer modules provides a comprehensive and integrated analysis of ATP metabolism and molecular motion dynamics. This relatively fast technique could be potentially useful for studying metabolic disorders in skeletal muscle.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,VA North Texas Health Care System, Dallas, Texas
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29
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Alizai H, Chang G, Regatte RR. MR Imaging of the Musculoskeletal System Using Ultrahigh Field (7T) MR Imaging. PET Clin 2019; 13:551-565. [PMID: 30219187 DOI: 10.1016/j.cpet.2018.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
MR imaging is an indispensable instrument for the diagnosis of musculoskeletal diseases. In vivo MR imaging at 7T offers many advantages, including increased signal-to-noise ratio, higher spatial resolution, improved spectral resolution for spectroscopy, improved sensitivity for X-nucleus imaging, and decreased image acquisition times. There are also however technical challenges of imaging at a higher field strength compared with 1.5 and 3T MR imaging systems. We discuss the many potential opportunities as well as the challenges presented by 7T MR imaging systems and highlight recent developments in in vivo research imaging of musculoskeletal applications in general and cartilage, skeletal muscle, and bone in particular.
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Affiliation(s)
- Hamza Alizai
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA.
| | - Gregory Chang
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA
| | - Ravinder R Regatte
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA
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30
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Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 250] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
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31
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Menon RG, Chang G, Regatte RR. The Emerging Role of 7 Tesla MRI in Musculoskeletal Imaging. CURRENT RADIOLOGY REPORTS 2018. [DOI: 10.1007/s40134-018-0286-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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32
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Zhao X, Song HK, Wehrli FW. In vivo bone 31 P relaxation times and their implications on mineral quantification. Magn Reson Med 2018; 80:2514-2524. [PMID: 29744923 PMCID: PMC6226373 DOI: 10.1002/mrm.27230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 03/13/2018] [Accepted: 03/31/2018] [Indexed: 12/23/2022]
Abstract
PURPOSE The intersubject variations in bone phosphorus-31 (31 P) T1 and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msubsup><mml:mi>T</mml:mi> <mml:mn>2</mml:mn> <mml:mo>*</mml:mo></mml:msubsup> </mml:mrow> </mml:math> , as well as the implications on in vivo 31 P MRI-based bone mineral quantification, were investigated at 3T field strength. METHODS A technique that isolates the bone signal from the composite in vivo 31 P spectrum was first evaluated via simulation and experiments ex vivo and subsequently applied to measure the T1 of bone 31 P collectively with a spectroscopic saturation recovery sequence in a group of healthy subjects aged 26 to 76 years. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msubsup><mml:mi>T</mml:mi> <mml:mn>2</mml:mn> <mml:mo>*</mml:mo></mml:msubsup> </mml:mrow> </mml:math> was derived from the bone signal linewidth. The density of bone 31 P was derived for all subjects from 31 P zero TE images acquired in the same scan session using the measured relaxation times. Test-retest experiments were also performed to evaluate repeatability of this in vivo MRI-based bone mineral quantification protocol. RESULTS The T1 obtained in vivo using the proposed spectral separation method combined with saturation recovery sequence is 38.4 ± 1.5 s for the subjects studied. Average 31 P density found was 6.40 ± 0.58 mol/L (corresponding to 1072 ± 98 mg/cm3 mineral density), in good agreement with an earlier study in specimens from donors of similar age range. Neither the relaxation times (P = 0.18 for T1 , P = 0.99 for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msubsup><mml:mi>T</mml:mi> <mml:mn>2</mml:mn> <mml:mo>*</mml:mo></mml:msubsup> </mml:mrow> </mml:math> ) nor 31 P density (P = 0.55) were found to correlate with subject age. Average coefficients of variation for the repeat study were 1.5%, 2.6%, and 4.4% for bone 31 P T1 , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msubsup><mml:mi>T</mml:mi> <mml:mn>2</mml:mn> <mml:mo>*</mml:mo></mml:msubsup> </mml:mrow> </mml:math> , and density, respectively. CONCLUSION Neither 31 P T1 nor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msubsup><mml:mi>T</mml:mi> <mml:mn>2</mml:mn> <mml:mo>*</mml:mo></mml:msubsup> </mml:mrow> </mml:math> varies significantly in healthy adults across a 50-year age range, therefore obviating the need for subject-specific measurements.
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Affiliation(s)
- Xia Zhao
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hee Kwon Song
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Santos-Díaz A, Obruchkov SI, Schulte RF, Noseworthy MD. Phosphorus magnetic resonance spectroscopic imaging using flyback echo planar readout trajectories. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2018; 31:553-564. [PMID: 29383517 DOI: 10.1007/s10334-018-0675-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/09/2018] [Accepted: 01/09/2018] [Indexed: 01/07/2023]
Abstract
OBJECT To present and evaluate a fast phosphorus magnetic resonance spectroscopic imaging (MRSI) sequence using echo planar spectroscopic imaging with flyback readout gradient trajectories. MATERIALS AND METHODS Waveforms were designed and implemented using a 3 Tesla MRI system. 31P spectra were acquired with 2 × 2 cm2 and 3 × 3 cm2 resolution over a 20- and 21-cm field of view and spectral bandwidths up to 1923 Hz. The sequence was first tested using a 20-cm-diameter phosphate phantom, and subsequent in vivo tests were performed on healthy human calf muscles and brains from five volunteers. RESULTS Flyback EPSI achieved 10× and 7× reductions in acquisition time, with 68.0 ± 1.2 and 69.8 ± 2.2% signal-to-noise ratio (SNR) per unit of time efficiency (theoretical SNR efficiency was 74.5 and 76.4%) for the in vivo experiments, compared to conventional phase-encoded MRSI for the 2 × 2 cm2 and 3 × 3 cm2 resolution waveforms, respectively. Statistical analysis showed no difference in the quantification of most metabolites. Time savings and SNR comparisons were consistent across phantom, leg and brain experiments. CONCLUSION EPSI using flyback readout trajectories was found to be a reliable alternative for acquiring 31P-MRSI data in a shorter acquisition time.
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Affiliation(s)
- Alejandro Santos-Díaz
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.,Imaging Research Center, St. Joseph's Healthcare, Hamilton, ON, Canada
| | - Sergei I Obruchkov
- Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | | | - Michael D Noseworthy
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada. .,Imaging Research Center, St. Joseph's Healthcare, Hamilton, ON, Canada. .,Department of Electrical and Computer Engineering, McMaster University, Engineering Technology Building, ETB-406, 1280 Main St. West, Hamilton, ON, L8S 4K1, Canada.
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Lebon V, Jan S, Fontyn Y, Tiret B, Pottier G, Jaumain E, Valette J. Using 31P-MRI of hydroxyapatite for bone attenuation correction in PET-MRI: proof of concept in the rodent brain. EJNMMI Phys 2017; 4:16. [PMID: 28466279 PMCID: PMC5413461 DOI: 10.1186/s40658-017-0183-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 04/20/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The correction of γ-photon attenuation in PET-MRI remains a critical issue, especially for bone attenuation. This problem is of great importance for brain studies due to the density of the skull. Current techniques for skull attenuation correction (AC) provide indirect estimates of cortical bone density, leading to inaccurate estimates of brain activity. The purpose of this study was to develop an alternate method for bone attenuation correction based on NMR. The proposed approach relies on the detection of hydroxyapatite crystals by zero echo time (ZTE) MRI of 31P, providing individual and quantitative assessment of bone density. This work presents a proof of concept of this approach. The first step of the method is a calibration experiment to determine the conversion relationship between the 31P signal and the linear attenuation coefficient μ. Then 31P-ZTE was performed in vivo in rodent to estimate the μ-map of the skull. 18F-FDG PET data were acquired in the same animal and reconstructed with three different AC methods: 31P-based AC, AC neglecting the bone and the gold standard, CT-based AC, used to comparison for the other two methods. RESULTS The calibration experiment provided a conversion factor of 31P signal into μ. In vivo 31P-ZTE made it possible to acquire 3D images of the rat skull. Brain PET images showed underestimation of 18F activity in peripheral regions close to the skull when AC neglected the bone (as compared with CT-based AC). The use of 31P-derived μ-map for AC leads to increased peripheral activity, and therefore a global overestimation of brain 18F activity. CONCLUSIONS In vivo 31P-ZTE MRI of hydroxyapatite provides μ-map of the skull, which can be used for attenuation correction of 18F-FDG PET images. This study is limited by several intrinsic biases associated with the size of the rat brain, which are unlikely to affect human data on a clinical PET-MRI system.
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Affiliation(s)
- Vincent Lebon
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), MIRCen, Fontenay-aux-Roses, France.
- Centre National de la Recherche Scientifique (CNRS), Neurodegenerative Diseases Laboratory, Université Paris-Sud, Université Paris-Saclay, UMR 9199, Fontenay-aux-Roses, France.
| | - Sébastien Jan
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), SHFJ, Orsay, France
- Inserm/CEA/Université Paris Sud, Université Paris-Saclay, UMR 1023-CNRS ERL 9218, IMIV, Orsay, France
| | - Yoann Fontyn
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), SHFJ, Orsay, France
- Inserm/CEA/Université Paris Sud, Université Paris-Saclay, UMR 1023-CNRS ERL 9218, IMIV, Orsay, France
| | - Brice Tiret
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), MIRCen, Fontenay-aux-Roses, France
- Centre National de la Recherche Scientifique (CNRS), Neurodegenerative Diseases Laboratory, Université Paris-Sud, Université Paris-Saclay, UMR 9199, Fontenay-aux-Roses, France
| | - Géraldine Pottier
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), SHFJ, Orsay, France
- Inserm/CEA/Université Paris Sud, Université Paris-Saclay, UMR 1023-CNRS ERL 9218, IMIV, Orsay, France
| | - Emilie Jaumain
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), SHFJ, Orsay, France
- Inserm/CEA/Université Paris Sud, Université Paris-Saclay, UMR 1023-CNRS ERL 9218, IMIV, Orsay, France
| | - Julien Valette
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomedicale (I2BM), MIRCen, Fontenay-aux-Roses, France
- Centre National de la Recherche Scientifique (CNRS), Neurodegenerative Diseases Laboratory, Université Paris-Sud, Université Paris-Saclay, UMR 9199, Fontenay-aux-Roses, France
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Wang CY, Liu Y, Huang S, Griswold MA, Seiberlich N, Yu X. 31 P magnetic resonance fingerprinting for rapid quantification of creatine kinase reaction rate in vivo. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3786. [PMID: 28915341 PMCID: PMC5690599 DOI: 10.1002/nbm.3786] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/14/2017] [Accepted: 07/12/2017] [Indexed: 05/25/2023]
Abstract
The purpose of this work was to develop a 31 P spectroscopic magnetic resonance fingerprinting (MRF) method for fast quantification of the chemical exchange rate between phosphocreatine (PCr) and adenosine triphosphate (ATP) via creatine kinase (CK). A 31 P MRF sequence (CK-MRF) was developed to quantify the forward rate constant of ATP synthesis via CK ( kfCK), the T1 relaxation time of PCr ( T1PCr), and the PCr-to-ATP concentration ratio ( MRPCr). The CK-MRF sequence used a balanced steady-state free precession (bSSFP)-type excitation with ramped flip angles and a unique saturation scheme sensitive to the exchange between PCr and γATP. Parameter estimation was accomplished by matching the acquired signals to a dictionary generated using the Bloch-McConnell equation. Simulation studies were performed to examine the susceptibility of the CK-MRF method to several potential error sources. The accuracy of nonlocalized CK-MRF measurements before and after an ischemia-reperfusion (IR) protocol was compared with the magnetization transfer (MT-MRS) method in rat hindlimb at 9.4 T (n = 14). The reproducibility of CK-MRF was also assessed by comparing CK-MRF measurements with both MT-MRS (n = 17) and four angle saturation transfer (FAST) (n = 7). Simulation results showed that CK-MRF quantification of kfCK was robust, with less than 5% error in the presence of model inaccuracies including dictionary resolution, metabolite T2 values, inorganic phosphate metabolism, and B1 miscalibration. Estimation of kfCK by CK-MRF (0.38 ± 0.02 s-1 at baseline and 0.42 ± 0.03 s-1 post-IR) showed strong agreement with MT-MRS (0.39 ± 0.03 s-1 at baseline and 0.44 ± 0.04 s-1 post-IR). kfCK estimation was also similar between CK-MRF and FAST (0.38 ± 0.02 s-1 for CK-MRF and 0.38 ± 0.11 s-1 for FAST). The coefficient of variation from 20 s CK-MRF quantification of kfCK was 42% of that by 150 s MT-MRS acquisition and was 12% of that by 20 s FAST acquisition. This study demonstrates the potential of a 31 P spectroscopic MRF framework for rapid, accurate and reproducible quantification of chemical exchange rate of CK in vivo.
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Affiliation(s)
- Charlie Y. Wang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Yuchi Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Shuying Huang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Mark A. Griswold
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio
| | - Nicole Seiberlich
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio
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Liu Y, Gu Y, Yu X. Assessing tissue metabolism by phosphorous-31 magnetic resonance spectroscopy and imaging: a methodology review. Quant Imaging Med Surg 2017; 7:707-726. [PMID: 29312876 PMCID: PMC5756783 DOI: 10.21037/qims.2017.11.03] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/11/2017] [Indexed: 01/11/2023]
Abstract
Many human diseases are caused by an imbalance between energy production and demand. Magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide the unique opportunity for in vivo assessment of several fundamental events in tissue metabolism without the use of ionizing radiation. Of particular interest, phosphate metabolites that are involved in ATP generation and utilization can be quantified noninvasively by phosphorous-31 (31P) MRS/MRI. Furthermore, 31P magnetization transfer (MT) techniques allow in vivo measurement of metabolic fluxes via creatine kinase (CK) and ATP synthase. However, a major impediment for the clinical applications of 31P-MRS/MRI is the prohibitively long acquisition time and/or the low spatial resolution that are necessary to achieve adequate signal-to-noise ratio. In this review, current 31P-MRS/MRI techniques used in basic science and clinical research are presented. Recent advances in the development of fast 31P-MRS/MRI methods are also discussed.
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Affiliation(s)
- Yuchi Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Yuning Gu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
- Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA
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Hooijmans MT, Doorenweerd N, Baligand C, Verschuuren JJGM, Ronen I, Niks EH, Webb AG, Kan HE. Spatially localized phosphorous metabolism of skeletal muscle in Duchenne muscular dystrophy patients: 24-month follow-up. PLoS One 2017; 12:e0182086. [PMID: 28763477 PMCID: PMC5538641 DOI: 10.1371/journal.pone.0182086] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/12/2017] [Indexed: 12/29/2022] Open
Abstract
Objectives To assess the changes in phosphodiester (PDE)-levels, detected by 31P magnetic resonance spectroscopy (MRS), over 24-months to determine the potential of PDE as marker for muscle tissue changes in Duchenne Muscular Dystrophy (DMD) patients. Methods Spatially resolved phosphorous datasets were acquired in the right lower leg of 18 DMD patients (range: 5–15.4 years) and 12 age-matched healthy controls (range: 5–14 years) at three time-points (baseline, 12-months, and 24-months) using a 7T MR-System (Philips Achieva). 3-point Dixon images were acquired at 3T (Philips Ingenia) to determine muscle fat fraction. Analyses were done for six muscles that represent different stages of muscle wasting. Differences between groups and time-points were assessed with non-parametric tests with correction for multiple comparisons. Coefficient of variance (CV) were determined for PDE in four healthy adult volunteers in high and low signal-to-noise ratio (SNR) datasets. Results PDE-levels were significantly higher (two-fold) in DMD patients compared to controls in all analyzed muscles at almost every time point and did not change over the study period. Fat fraction was significantly elevated in all muscles at all time points compared to healthy controls, and increased significantly over time, except in the tibialis posterior muscle. The mean within subject CV for PDE-levels was 4.3% in datasets with high SNR (>10:1) and 5.7% in datasets with low SNR. Discussion and conclusion The stable two-fold increase in PDE-levels found in DMD patients in muscles with different levels of muscle wasting over 2-year time, including DMD patients as young as 5.5 years-old, suggests that PDE-levels may increase very rapidly early in the disease process and remain elevated thereafter. The low CV values in high and low SNR datasets show that PDE-levels can be accurately and reproducibly quantified in all conditions. Our data confirms the great potential of PDE as a marker for muscle tissue changes in DMD patients.
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Affiliation(s)
- M. T. Hooijmans
- Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
| | - N. Doorenweerd
- Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - C. Baligand
- Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | | | - I. Ronen
- Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - E. H. Niks
- Dept of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - A. G. Webb
- Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - H. E. Kan
- Dept of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
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Lee BY, Zhu XH, Rupprecht S, Lanagan MT, Yang QX, Chen W. Large improvement of RF transmission efficiency and reception sensitivity for human in vivo 31P MRS imaging using ultrahigh dielectric constant materials at 7T. Magn Reson Imaging 2017; 42:158-163. [PMID: 28739392 DOI: 10.1016/j.mri.2017.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/16/2017] [Accepted: 07/20/2017] [Indexed: 10/19/2022]
Abstract
In vivo31P MRS provides a unique and important imaging tool for studying high-energy phosphate metabolism and bioenergetics noninvasively. However, compared to 1H MRS, 31P MRS with a relatively low gyromagnetic ratio (γ) has a lower and limited sensitivity even at ultrahigh field. The proof of concept has been recently demonstrated that the use of high dielectric constant (HDC) materials between RF coil and object sample could increase MRI signal and reduce required RF transmission power for reaching the same RF pulse flip angle in the region of interest. For low-γ MRS applications operated at relatively lower frequency, however, it demands the dielectric materials with a much higher permittivity for achieving optimal performance. We conducted a 31P MRS imaging study using ultra-HDC (uHDC; with a relative permittivity of ~1200) material blocks incorporated with an RF volume coil at ultrahigh field of 7.0T. The experimental results from phantom and human calf muscle demonstrate that the uHDC technique significantly enhanced RF magnetic transmit field (B1+) and reception field (B1-) and the gain could reach up to two folds in the tissue near the uHDC blocks. The overall results indicate that the incorporation of the uHDC materials having an appropriate permittivity value with a RF coil can significantly increase detection sensitivity and reduces RF transmission power for X-nuclei MRS applications at ultrahigh field. The uHDC technology could provide an efficient, cost-effective engineering solution for achieving high detection sensitivity and concurrently minimizing tissue heating concern for human MRS and MRI applications.
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Affiliation(s)
- Byeong-Yeul Lee
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, MN, USA
| | - Xiao-Hong Zhu
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, MN, USA
| | - Sebastian Rupprecht
- Center for NMR Research, Department of Radiology, Pennsylvania State College of Medicine, Hershey, PA, USA
| | - Michael T Lanagan
- Department of Engineering Science and Mechanics, The Pennsylvania State College of Engineering, University Park, PA, USA
| | - Qing X Yang
- Center for NMR Research, Department of Radiology, Pennsylvania State College of Medicine, Hershey, PA, USA.
| | - Wei Chen
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, MN, USA.
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Tayari N, Heerschap A, Scheenen TW, Kobus T. In vivo MR spectroscopic imaging of the prostate, from application to interpretation. Anal Biochem 2017; 529:158-170. [DOI: 10.1016/j.ab.2017.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 12/23/2016] [Accepted: 02/01/2017] [Indexed: 12/15/2022]
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Khegai O, Madelin G, Brown R, Parasoglou P. Dynamic phosphocreatine imaging with unlocalized pH assessment of the human lower leg muscle following exercise at 3T. Magn Reson Med 2017; 79:974-980. [PMID: 28560829 DOI: 10.1002/mrm.26728] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 12/16/2022]
Abstract
PURPOSE To develop a high temporal resolution imaging method that measures muscle-specific phosphocreatine (PCr) resynthesis time constant (τPCr ) and pH changes in muscles of the lower leg following exercise on a clinical 3T MRI scanner. METHODS We developed a frequency-selective 3D non-Cartesian FLORET sequence to measure PCr with 17-mm nominal isotropic resolution (28 mm actual resolution) and 6-s temporal resolution to capture dynamic metabolic muscle activity. The sequence was designed to additionally collect inorganic phosphate spectra for pH quantification, which were localized using sensitivity profiles of individual coil elements. Nineteen healthy volunteers were scanned while performing a plantar flexion exercise on an in-house developed ergometer. Data were acquired with a dual-tuned multichannel coil array that enabled phosphorus imaging and proton localization for muscle segmentation. RESULTS After a 90-s plantar flexion exercise at 0.66 Hz with resistance set to 40% of the maximum voluntary contraction, τPCr was estimated at 22.9 ± 8.8 s (mean ± standard deviation) with statistical coefficient of determination r2 = 0.89 ± 0.05. The corresponding pH values after exercise were in the range of 6.9-7.1 in the gastrocnemius muscle. CONCLUSION The developed technique allows measurement of muscle-specific PCr resynthesis kinetics and pH changes following exercise, with a temporal resolution and accuracy comparable to that of single voxel 31 P-MRS sequences. Magn Reson Med 79:974-980, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Oleksandr Khegai
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Guillaume Madelin
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Ryan Brown
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.,NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA
| | - Prodromos Parasoglou
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
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Iterative reconstruction of radially-sampled 31 P bSSFP data using prior information from 1 H MRI. Magn Reson Imaging 2017; 37:147-158. [DOI: 10.1016/j.mri.2016.11.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 10/10/2016] [Accepted: 11/17/2016] [Indexed: 12/18/2022]
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Niess F, Fiedler GB, Schmid AI, Goluch S, Kriegl R, Wolzt M, Moser E, Meyerspeer M. Interleaved multivoxel 31 P MR spectroscopy. Magn Reson Med 2017; 77:921-927. [PMID: 26914656 PMCID: PMC4996323 DOI: 10.1002/mrm.26172] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/16/2016] [Accepted: 01/27/2016] [Indexed: 12/27/2022]
Abstract
PURPOSE Separate measurements are required when investigating multiple exercising muscles with singlevoxel-localized dynamic 31 P-MRS. With multivoxel spectroscopy, 31 P-MRS time-series spectra are acquired from multiple independent regions during one exercise-recovery experiment with the same time resolution as for singlevoxel measurements. METHODS Multiple independently selected volumes were localized using temporally interleaved semi-LASER excitations at 7T. Signal loss caused by mutual saturation from shared excitation or refocusing slices was quantified at partial and full overlap, and potential contamination was investigated in phantom measurements. During an exercise-recovery experiment both gastrocnemius medialis and soleus of two healthy volunteers were measured using multivoxel acquisitions with a total TR of 6 s, while avoiding overlap of excitation slices. RESULTS Signal reduction by shared adiabatic refocusing slices selected 1 s after the preceding voxel was between 10% (full overlap) and 20% (half overlap), in a phantom measurement. In vivo data were acquired from both muscles within the same exercise experiment, with 13-18% signal reduction. Spectra show phosphocreatine, inorganic phosphate, adenosine-triposphate, phosphomonoesters, and phosphodiesters. CONCLUSION Signal decrease was relatively low compared to the 2-fold increase in information. The approach could help to improve the understanding in metabolic research and is applicable to other organs and nuclei. Magn Reson Med 77:921-927, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Fabian Niess
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
- Faculty of PhysicsTechnical University of ViennaViennaAustria
| | - Georg B. Fiedler
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Albrecht I. Schmid
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Sigrun Goluch
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Roberta Kriegl
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Michael Wolzt
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Ewald Moser
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
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43
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Purvis LAB, Clarke WT, Valkovič L, Levick C, Pavlides M, Barnes E, Cobbold JF, Robson MD, Rodgers CT. Phosphodiester content measured in human liver by in vivo 31 P MR spectroscopy at 7 tesla. Magn Reson Med 2017; 78:2095-2105. [PMID: 28244131 PMCID: PMC5697655 DOI: 10.1002/mrm.26635] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 12/19/2022]
Abstract
Purpose Phosphorus (31P) metabolites are emerging liver disease biomarkers. Of particular interest are phosphomonoester and phosphodiester (PDE) “peaks” that comprise multiple overlapping resonances in 31P spectra. This study investigates the effect of improved spectral resolution at 7 Tesla (T) on quantifying hepatic metabolites in cirrhosis. Methods Five volunteers were scanned to determine metabolite T1s. Ten volunteers and 11 patients with liver cirrhosis were scanned at 7T. Liver spectra were acquired in 28 min using a 16‐channel 31P array and 3D chemical shift imaging. Concentrations were calculated using γ‐adenosine‐triphosphate (γ‐ATP) = 2.65 mmol/L wet tissue. Results T1 means ± standard deviations: phosphatidylcholine 1.05 ± 0.28 s, nicotinamide‐adenine‐dinucleotide (NAD+) 2.0 ± 1.0 s, uridine‐diphosphoglucose (UDPG) 3.3 ± 1.4 s. Concentrations in healthy volunteers: α‐ATP 2.74 ± 0.11 mmol/L wet tissue, inorganic phosphate 2.23 ± 0.20 mmol/L wet tissue, glycerophosphocholine 2.34 ± 0.46 mmol/L wet tissue, glycerophosphoethanolamine 1.50 ± 0.28 mmol/L wet tissue, phosphocholine 1.06 ± 0.16 mmol/L wet tissue, phosphoethanolamine 0.77 ± 0.14 mmol/L wet tissue, NAD+ 2.37 ± 0.14 mmol/L wet tissue, UDPG 2.00 ± 0.22 mmol/L wet tissue, phosphatidylcholine 1.38 ± 0.31 mmol/L wet tissue. Inorganic phosphate and phosphatidylcholine concentrations were significantly lower in patients; glycerophosphoethanolamine concentrations were significantly higher (P < 0.05). Conclusion We report human in vivo hepatic T1s for phosphatidylcholine, NAD+, and UDPG for the first time at 7T. Our protocol allows high signal‐to‐noise, repeatable measurement of metabolite concentrations in human liver. The splitting of PDE into its constituent peaks at 7T may allow more insight into changes in metabolism. Magn Reson Med 78:2095–2105, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Lucian A B Purvis
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - William T Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.,Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Christina Levick
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Michael Pavlides
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom.,Translational Gastroenterology Unit, University of Oxford, United Kingdom
| | - Eleanor Barnes
- Translational Gastroenterology Unit, University of Oxford, United Kingdom
| | - Jeremy F Cobbold
- Translational Gastroenterology Unit, University of Oxford, United Kingdom
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Christopher T Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, United Kingdom
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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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Hooijmans MT, Niks EH, Burakiewicz J, Verschuuren JJGM, Webb AG, Kan HE. Elevated phosphodiester and T 2 levels can be measured in the absence of fat infiltration in Duchenne muscular dystrophy patients. NMR IN BIOMEDICINE 2017; 30:e3667. [PMID: 27859827 DOI: 10.1002/nbm.3667] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/10/2016] [Accepted: 10/10/2016] [Indexed: 05/27/2023]
Abstract
Quantitative MRI and MRS are increasingly important as non-invasive outcome measures in therapy development for Duchenne muscular dystrophy (DMD). Many studies have focussed on individual measures such as fat fraction and metabolite levels in relation to age and functionality, but much less attention has been given to how these indices relate to each other. Here, we assessed spatially resolved metabolic changes in leg muscles of DMD patients, and classified muscles according to the degree of fat replacement compared with healthy controls. Quantitative MRI (three-point Dixon and multi-spin echo without fat suppression and a tri-exponential fit) and 2D-CSI 31 P MRS scans were obtained from 18 DMD patients and 12 healthy controls using a 3 T and a 7 T MR scanner. Metabolite levels, T2 values and fat fraction were individually assessed for five lower leg muscles. In muscles with extensive fat replacement, phosphodiester over adenosine triphosphate (PDE/ATP), inorganic phosphate over phosphocreatine, intracellular tissue pH and T2 were significantly increased compared with healthy controls. In contrast, in muscles without extensive fat replacement, only PDE/ATP and T2 values were significantly elevated. Overall, our results show that PDE levels and T2 values increase prior to the occurrence of fat replacement and remain elevated in later stages of the disease. This suggests that these individual measures could not only function as early markers for muscle damage but also reflect potentially reversible pathology in the more advanced stages.
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Affiliation(s)
- M T Hooijmans
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - E H Niks
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - J Burakiewicz
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - J J G M Verschuuren
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - A G Webb
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
| | - H E Kan
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands
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Valkovič L, Clarke WT, Purvis LA, Schaller B, Robson MD, Rodgers CT. Adiabatic excitation for 31 P MR spectroscopy in the human heart at 7 T: A feasibility study. Magn Reson Med 2016; 78:1667-1673. [PMID: 28000961 PMCID: PMC5645675 DOI: 10.1002/mrm.26576] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 11/18/2022]
Abstract
Purpose Phosphorus magnetic resonance spectroscopy (31P‐MRS) provides a unique tool for assessing cardiac energy metabolism, often quantified using the phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio. Surface coils are typically used for excitation for 31P‐MRS, but they create an inhomogeneous excitation field across the myocardium, producing undesirable, spatially varying partial saturation. Therefore, we implemented adiabatic excitation in a 3D chemical shift imaging (CSI) sequence for cardiac 31P‐MRS at 7 Tesla (T). Methods We optimized an adiabatic half passage pulse with bandwidth sufficient to excite PCr and γ‐ATP together. In addition, the CSI sequence was modified to allow interleaved excitation of PCr and γ‐ATP, then 2,3‐DPG, to enable PCr/ATP determination with blood correction. Nine volunteers were scanned at 2 transmit voltages to confirm that measured PCr/ATP was independent of
B1+ (i.e. over the adiabatic threshold). Six septal voxels were evaluated for each volunteer. Results Phantom experiments showed that adiabatic excitation can be reached at the depth of the heart using our pulse. The mean evaluated cardiac PCr/ATP ratio from all 9 volunteers corrected for blood signal was 2.14 ± 0.16. Comparing the two acquisitions with different voltages resulted in a minimal mean difference of
−0.005. Conclusion Adiabatic excitation is possible in the human heart at 7 T, and gives consistent PCr/ATP ratios. Magn Reson Med 78:1667–1673, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Ladislav Valkovič
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
- Department of Imaging MethodsInstitute of Measurement Science, Slovak Academy of SciencesBratislavaSlovakia
| | - William T. Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Lucian A.B. Purvis
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Benoit Schaller
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUnited Kingdom
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Valkovič L, Chmelík M, Meyerspeer M, Gagoski B, Rodgers CT, Krššák M, Andronesi OC, Trattnig S, Bogner W. Dynamic 31 P-MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T. NMR IN BIOMEDICINE 2016; 29:1825-1834. [PMID: 27862510 PMCID: PMC5132121 DOI: 10.1002/nbm.3662] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/19/2016] [Accepted: 09/28/2016] [Indexed: 05/06/2023]
Abstract
Phosphorus MRSI (31 P-MRSI) using a spiral-trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle. The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunteers, who performed a plantar flexion exercise inside a whole-body 7 T MR scanner using an MR-compatible ergometer and a surface coil. In five volunteers the knee was flexed (~60°) to shift the major workload from the gastrocnemii to the soleus muscle. Spiral-encoded MRSI provided 16-25 times faster mapping with a better point spread function than elliptical phase-encoded MRSI with the same matrix size. The inevitable trade-off for the increased temporal resolution was a reduced signal-to-noise ratio, but this was acceptable. The phosphocreatine (PCr) depletion caused by exercise at 0° knee angulation was significantly higher in both gastrocnemii than in the soleus (i.e. 64.8 ± 19.6% and 65.9 ± 23.6% in gastrocnemius lateralis and medialis versus 15.3 ± 8.4% in the soleus). Spiral-encoded 31 P-MRSI is a powerful tool for dynamic mapping of exercising muscle oxidative metabolism, including localized assessment of PCr concentrations, pH and maximal oxidative flux with high temporal and spatial resolution.
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Affiliation(s)
- Ladislav Valkovič
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
- Department of Imaging Methods, Institute of Measurement ScienceSlovak Academy of SciencesBratislavaSlovakia
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUK
| | - Marek Chmelík
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Martin Meyerspeer
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Borjan Gagoski
- Fetal Neonatal Neuroimaging and Developmental Science CenterBoston Children's HospitalBostonMassachusettsUSA
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUK
| | - Martin Krššák
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Ovidiu C. Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Siegfried Trattnig
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Wolfgang Bogner
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
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Ren J, Sherry AD, Malloy CR. Efficient 31 P band inversion transfer approach for measuring creatine kinase activity, ATP synthesis, and molecular dynamics in the human brain at 7 T. Magn Reson Med 2016; 78:1657-1666. [PMID: 27868234 DOI: 10.1002/mrm.26560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/16/2016] [Accepted: 11/03/2016] [Indexed: 01/28/2023]
Abstract
PURPOSE To develop an efficient 31 P magnetic resonance spectroscopy (MRS) method for measuring creatine kinase (CK) activity, adenosine triphosphate (ATP) synthesis, and motion dynamics in the human brain at 7 Tesla (T). METHODS Three band inversion modules differing in center frequency were used to induce magnetization transfer (MT) effect in three exchange pathways: (i) CK-mediated reaction PCr → γ-ATP; (ii) de novo ATP synthesis Pi → γ-ATP; and (iii) ATP intramolecular 31 P-31 P cross-relaxation γ-(α-) ↔ β-ATP. The resultant MT data were analyzed using a 5-pool model in the format of magnetization matrix according to Bloch-McConnell-Solomon formalism. RESULTS With a repetition time (TR) of 4 s, the scan time for each module was approximately 8 min. The rate constants were kPCr → γATP 0.38 ± 0.02 s-1 , kPi → γATP 0.19 ± 0.02 s-1 , and σγ(α) ↔ βATP 0.19 ± 0.04 s-1 , corresponding to ATP rotation correlation time τc (0.8 ± 0.2) ·10-7 s. The T1 relaxation times were Pi 7.26 ± 1.76 s, PCr 5.99 ± 0.58 s, γ-ATP 0.98 ± 0.07 s, α-ATP 0.95 ± 0.04 s, and β-ATP 0.68 ± 0.03 s. CONCLUSION Short-TR band inversion modules provide a time-efficient way of measuring brain ATP metabolism and could be useful in studying metabolic disorders in brain diseases. Magn Reson Med 78:1657-1666, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,VA North Texas Health Care System, Dallas, Texas, USA
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Trattnig S, Bogner W, Gruber S, Szomolanyi P, Juras V, Robinson S, Zbýň Š, Haneder S. Clinical applications at ultrahigh field (7 T). Where does it make the difference? NMR IN BIOMEDICINE 2016; 29:1316-34. [PMID: 25762432 DOI: 10.1002/nbm.3272] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/20/2015] [Accepted: 01/22/2015] [Indexed: 05/11/2023]
Abstract
Presently, three major MR vendors provide commercial 7-T units for clinical research under ethical permission, with the number of operating 7-T systems having increased to over 50. This rapid increase indicates the growing interest in ultrahigh-field MRI because of improved clinical results with regard to morphological as well as functional and metabolic capabilities. As the signal-to-noise ratio scales linearly with the field strength (B0 ) of the scanner, the most obvious application at 7 T is to obtain higher spatial resolution in the brain, musculoskeletal system and breast. Of specific clinical interest for neuro-applications is the cerebral cortex at 7 T, for the detection of changes in cortical structure as a sign of early dementia, as well as for the visualization of cortical microinfarcts and cortical plaques in multiple sclerosis. In the imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology can be visualized with excellent resolution. The dynamic and static blood oxygenation level-dependent contrast increases linearly with the field strength, which significantly improves the pre-surgical evaluation of eloquent areas before tumor removal. Using susceptibility-weighted imaging, the plaque-vessel relationship and iron accumulation in multiple sclerosis can be visualized for the first time. Multi-nuclear clinical applications, such as sodium imaging for the evaluation of repair tissue quality after cartilage transplantation and (31) P spectroscopy for the differentiation between non-alcoholic benign liver disease and potentially progressive steatohepatitis, are only possible at ultrahigh fields. Although neuro- and musculoskeletal imaging have already demonstrated the clinical superiority of ultrahigh fields, whole-body clinical applications at 7 T are still limited, mainly because of the lack of suitable coils. The purpose of this article was therefore to review the clinical studies that have been performed thus far at 7 T, compared with 3 T, as well as those studies performed at 7 T that cannot be routinely performed at 3 T. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- CD Laboratory for Clinical Molecular MR Imaging
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Stephan Gruber
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Pavol Szomolanyi
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Department of Imaging Methods, Institute of Measurement Sciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Vladimir Juras
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Department of Imaging Methods, Institute of Measurement Sciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Simon Robinson
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Štefan Zbýň
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Stefan Haneder
- Vascular and Abdominal Imaging, Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany
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50
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Ren J, Sherry AD, Malloy CR. A simple approach to evaluate the kinetic rate constant for ATP synthesis in resting human skeletal muscle at 7 T. NMR IN BIOMEDICINE 2016; 29:1240-8. [PMID: 25943328 PMCID: PMC4673044 DOI: 10.1002/nbm.3310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 05/11/2023]
Abstract
Inversion transfer (IT) is a well-established technique with multiple attractive features for analysis of kinetics. However, its application in measurement of ATP synthesis rate in vivo has lagged behind the more common saturation transfer (ST) techniques. One well-recognized issue with IT is the complexity of data analysis in comparison with much simpler analysis by ST. This complexity arises, in part, because the γ-ATP spin is involved in multiple chemical reactions and magnetization exchanges, whereas Pi is involved in a single reaction, Pi → γ-ATP. By considering the reactions involving γ-ATP only as a lumped constant, the rate constant for the reaction of physiological interest, kPi→γATP , can be determined. Here, we present a new IT data analysis method to evaluate kPi→γATP using data collected from resting human skeletal muscle at 7 T. The method is based on the basic Bloch-McConnell equation, which relates kPi→γATP to m˙Pi, the rate of Pi magnetization change. The kPi→γATP value is accessed from m˙Pi data by more familiar linear correlation approaches. For a group of human subjects (n = 15), the kPi→γATP value derived for resting calf muscle was 0.066 ± 0.017 s(-1) , in agreement with literature-reported values. In this study we also explored possible time-saving strategies to speed up data acquisition for kPi→γATP evaluation using simulations. The analysis indicates that it is feasible to carry out a (31) P IT experiment in about 10 min or less at 7 T with reasonable outcome in kPi→γATP variance for measurement of ATP synthesis in resting human skeletal muscle. We believe that this new IT data analysis approach will facilitate the wide acceptance of IT to evaluate ATP synthesis rate in vivo. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Chemistry, University of Texas at Dallas, Richardson, TX75080
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX75390
- VA North Texas Health Care System, Dallas, TX75216
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