1
|
Bozymski B, Emir U, Dydak U, Shen X, Thomas MA, Özen A, Chiew M, Clarke W, Sawiak S. 3D ultra-short echo time 31P-MRSI with rosette k-space pattern: Feasibility and comparison with conventional weighted CSI. RESEARCH SQUARE 2024:rs.3.rs-4223790. [PMID: 38659806 PMCID: PMC11042414 DOI: 10.21203/rs.3.rs-4223790/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Phosphorus-31 magnetic resonance spectroscopic imaging (31P-MRSI) provides valuable non-invasive in vivo information on tissue metabolism but is burdened by poor sensitivity and prolonged scan duration. Ultra-short echo time (UTE) acquisitions minimize signal loss when probing signals with relatively short spin-spin relaxation time (T2), while also preventing first-order dephasing. Here, a three-dimensional (3D) UTE sequence with a rosette k-space trajectory is applied to 31P-MRSI at 3T. Conventional chemical shift imaging (CSI) employs highly regular Cartesian k-space sampling, susceptible to substantial artifacts when accelerated via undersampling. In contrast, this novel sequence's "petal-like" pattern offers incoherent sampling more suitable for compressed sensing (CS). These results showcase the competitive performance of UTE rosette 31P-MRSI against conventional weighted CSI with simulation, phantom, and in vivo leg muscle comparisons.
Collapse
Affiliation(s)
| | - Uzay Emir
- School of Health Sciences, Purdue University
| | | | - Xin Shen
- Radiology and Biomedical Imaging, University of California San Francisco
| | | | - Ali Özen
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg
| | - Mark Chiew
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences
| | - William Clarke
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences
| | - Stephen Sawiak
- Department of Clinical Neuroscience, University of Cambridge
| |
Collapse
|
2
|
Moyle DB, Kudiersky MN, Totton MN, Sassani DM, Nichols DS, Jenkins DT, Redgrave DJ, Baig DS, Nair DKPS, Majid PA, Ali DAN. Remote ischaemic conditioning for fatigue after stroke (RICFAST): A pilot randomised controlled trial. J Stroke Cerebrovasc Dis 2023; 32:107420. [PMID: 37832270 DOI: 10.1016/j.jstrokecerebrovasdis.2023.107420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 10/03/2023] [Accepted: 10/06/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Post stroke fatigue (PSF) affects 50 % of stroke survivors, and can be disabling. Remote ischaemic conditioning (RIC), can preserve mitochondrial function, improve tissue perfusion and may mitigate PSF. This pilot randomised controlled trial evaluates the safety and feasibility of using RIC for PSF and evaluated measures of cellular bioenergetics. METHODS 24 people with debilitating PSF (7 item Fatigue Severity Score, FSS-7 > 4) were randomised (1:1) in this single-centre phase 2 study to RIC (blood pressure cuff inflation around the upper arm 200 mmHg for 5 min followed by 5 min of deflation), or sham (inflation pressure 20 mmHg), repeated 4 cycles, 3 times per week for 6 weeks. Primary outcomes were safety, acceptability, and compliance. Secondary outcomes included FSS-7, 6 min walking test (6MWT), peak oxygen consumption (V̇O2peak), ventilatory anaerobic threshold (VAT), and muscle adenosine triphosphate (ATP) content measured using 31-phosphorous magnetic resonance spectroscopy of tibialis anterior. RESULTS RIC was safe (no serious adverse events, adverse events mild) and adherence excellent (91 % sessions completed). Exploratory analysis revealed lower FSS-7 scores in the RIC group compared to sham at 6 weeks (between group difference FSS-7 -0.7, 95 %CI -2.0 to 0.6), 3 months (-1.0, 95 %CI -2.2 to 0.2) and 6 months (-0.9, 95 %CI -2.0 to 0.2). There were trends towards increased VAT, increased muscle ATP content and improved 6MWT in the RIC group. DISCUSSION RIC is safe and acceptable for people with PSF and may result in clinically meaningful improvements in fatigue and muscle bioenergetics that require further investigation in larger studies.
Collapse
Affiliation(s)
| | | | | | - Dr Matilde Sassani
- Translational Brain Science, Institute of Metabolism and Systems Research, UK
| | | | - Dr Tom Jenkins
- Sheffield Institute for Translational Neurology, UK; Royal Perth Hospital, Western Australia, UK
| | | | | | | | | | - Dr Ali N Ali
- Sheffield Teaching Hospitals NIHR Biomedical Research Centre, University of Sheffield, UK.
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Haeufle DFB, Siegel J, Hochstein S, Gussew A, Schmitt S, Siebert T, Rzanny R, Reichenbach JR, Stutzig N. Energy Expenditure of Dynamic Submaximal Human Plantarflexion Movements: Model Prediction and Validation by in-vivo Magnetic Resonance Spectroscopy. Front Bioeng Biotechnol 2020; 8:622. [PMID: 32671034 PMCID: PMC7332772 DOI: 10.3389/fbioe.2020.00622] [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: 02/03/2020] [Accepted: 05/21/2020] [Indexed: 11/30/2022] Open
Abstract
To understand the organization and efficiency of biological movement, it is important to evaluate the energy requirements on the level of individual muscles. To this end, predicting energy expenditure with musculoskeletal models in forward-dynamic computer simulations is currently the most promising approach. However, it is challenging to validate muscle models in-vivo in humans, because access to the energy expenditure of single muscles is difficult. Previous approaches focused on whole body energy expenditure, e.g., oxygen consumption (VO2), or on thermal measurements of individual muscles by tracking blood flow and heat release (through measurements of the skin temperature). This study proposes to validate models of muscular energy expenditure by using functional phosphorus magnetic resonance spectroscopy (31P-MRS). 31P-MRS allows to measure phosphocreatine (PCr) concentration which changes in relation to energy expenditure. In the first 25 s of an exercise, PCr breakdown rate reflects ATP hydrolysis, and is therefore a direct measure of muscular enthalpy rate. This method was applied to the gastrocnemius medialis muscle of one healthy subject during repetitive dynamic plantarflexion movements at submaximal contraction, i.e., 20% of the maximum plantarflexion force using a MR compatible ergometer. Furthermore, muscle activity was measured by surface electromyography (EMG). A model (provided as open source) that combines previous models for muscle contraction dynamics and energy expenditure was used to reproduce the experiment in simulation. All parameters (e.g., muscle length and volume, pennation angle) in the model were determined from magnetic resonance imaging or literature (e.g., fiber composition), leaving no free parameters to fit the experimental data. Model prediction and experimental data on the energy supply rates are in good agreement with the validation phase (<25 s) of the dynamic movements. After 25 s, the experimental data differs from the model prediction as the change in PCr does not reflect all metabolic contributions to the energy expenditure anymore and therefore underestimates the energy consumption. This shows that this new approach allows to validate models of muscular energy expenditure in dynamic movements in vivo.
Collapse
Affiliation(s)
- Daniel F B Haeufle
- Multi-level Modeling in Motor Control and Rehabilitation Robotics, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Johannes Siegel
- Multi-level Modeling in Motor Control and Rehabilitation Robotics, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Motion and Exercise Science, Institute of Sport and Movement Science, University of Stuttgart, Stuttgart, Germany
| | - Stefan Hochstein
- Motion Science, Institute of Sport Science, Martin-Luther-University Halle, Halle, Germany
| | - Alexander Gussew
- Department of Radiology, University Hospital Halle (Saale), Halle, Germany
| | - Syn Schmitt
- Computational Biophysics and Biorobotics, Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.,Stuttgart Center of Simulation Science, University of Stuttgart, Stuttgart, Germany
| | - Tobias Siebert
- Department of Motion and Exercise Science, Institute of Sport and Movement Science, University of Stuttgart, Stuttgart, Germany
| | - Reinhard Rzanny
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University, Jena, Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University, Jena, Germany
| | - Norman Stutzig
- Department of Motion and Exercise Science, Institute of Sport and Movement Science, University of Stuttgart, Stuttgart, Germany
| |
Collapse
|
6
|
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.
Collapse
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
| | | |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Pouymayou B, Buehler T, Kreis R, Boesch C. Test-retest analysis of multiple 31 P magnetization exchange pathways using asymmetric adiabatic inversion. Magn Reson Med 2016; 78:33-39. [PMID: 27455454 DOI: 10.1002/mrm.26337] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/17/2016] [Indexed: 01/08/2023]
Abstract
PURPOSE A 31 P-MR inversion transfer (IT) method with a short adiabatic inversion pulse is proposed and its test-retest reliability was evaluated for two spectral fitting strategies. METHODS Assessment in a test-retest design (3 Tesla, vastus muscles, 12 healthy volunteers, 14 inversion times, 22 ms asymmetric adiabatic inversion pulse, adiabatic excitation); spectral fitting in Fitting Tool for Interrelated Arrays of Datasets (FitAID) and Java Magnetic Resonance User Interface (jMRUI); least squares solution of the Bloch-McConnell-Solomon matrix formalism including all 14 measured time-points with equal weighting. RESULTS The cohort averages of k[PCr→γ-ATP] (phosphocreatine, PCr; adenosine triphosphate, ATP) are 0.246 ± 0.050s-1 versus 0.254 ± 0.050s-1 , and k[Pi→γ-ATP] 0.086 ± 0.033s-1 versus 0.066 ± 0.034s-1 (average ± standard deviation, jMRUI versus FitAID). Coefficients of variation of the differences between test and retest are lowest (9.5%) for k[PCr→γ-ATP] fitted in FitAID, larger (15.2%) for the fit in jMRUI, and considerably larger for k[Pi→γ-ATP] fitted in FitAID (43.4%) or jMRUI (47.9%). The beginning of the IT effect can be observed with magnetizations above 92% for noninverted lines while inversion of the ATP resonances is better than -72%. CONCLUSION The performance of the asymmetric adiabatic pulse allows an accurate observation of IT effects even in the early phase; the least squares fit of the Bloch-McConnell-Solomon matrix formalism is robust; and the type of spectral fitting can influence the results significantly. Magn Reson Med 78:33-39, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Bertrand Pouymayou
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Tania Buehler
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| | - Roland Kreis
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| | - Chris Boesch
- Department of Clinical Research and Department of Radiology, University of Bern, Switzerland
| |
Collapse
|
11
|
Runge JH, van der Kemp WJM, Klomp DWJ, Luijten PR, Nederveen AJ, Stoker J. 2D AMESING multi-echo (31)P-MRSI of the liver at 7T allows transverse relaxation assessment and T2-weighted averaging for improved SNR. Magn Reson Imaging 2015; 34:219-26. [PMID: 26597833 DOI: 10.1016/j.mri.2015.10.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/03/2015] [Accepted: 10/12/2015] [Indexed: 01/06/2023]
Abstract
PURPOSE Liver diseases are a major global health concern often requiring invasive assessment by needle biopsy. (31)P magnetic resonance spectroscopic imaging (MRSI) allows non-invasive probing of important liver metabolites. Recently, the adiabatic multi-echo spectroscopic imaging sequence with spherical k-space sampling (AMESING) was introduced at 7T, enabling acquisition of T2 information. T2-weighed averaging of the multiple echoes improves signal-to-noise ratio (SNR). The purpose of our study was to implement AMESING MRSI of the liver at 3T and 7T, derive localized T2 information and compare T2-weighted average spectra in terms of SNR. METHODS Ten male volunteers underwent 2D AMESING MRSI at 3T and 7T after a minimum four-hour fast. SNR was calculated for PC, PE, Pi, GPE, GPC and α-ATP using maximum peak amplitudes and the SD of the noise. Metabolite peak ratios were calculated after fitting in jMRUI. SNR values and peak ratios were compared with the Wilcoxon signed-rank test. RESULTS For the first time liver metabolites' T2 values at 7T were measured: PE (55.6±3.5 ms), PC (51.2±2.3 ms), Pi (46.4±1.1 ms), GPE (44.0±0.8 ms), GPC (50.4±0.8 ms) and α-ATP (18.2±0.4 ms). SNR gain using T2-weighted averaging at 7T resulted in a 1.2× SNR gain. In conjunction with higher field strength and improved coil set-up T2-weighted averaging at 7T allowed a total 3.2× SNR gain compared to 3T FID-only. CONCLUSION AMESING 2D MRSI of the liver at 7T provides T2 values that allow T2-weighted averaging of data from multiple echoes resulting in improved SNR.
Collapse
Affiliation(s)
- Jurgen Henk Runge
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | - Wybe J M van der Kemp
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter R Luijten
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jaap Stoker
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
12
|
Schär M, Gabr RE, El-Sharkawy AMM, Steinberg A, Bottomley PA, Weiss RG. Two repetition time saturation transfer (TwiST) with spill-over correction to measure creatine kinase reaction rates in human hearts. J Cardiovasc Magn Reson 2015; 17:70. [PMID: 26253320 PMCID: PMC4529717 DOI: 10.1186/s12968-015-0175-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/21/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phosphorus saturation transfer (ST) magnetic resonance spectroscopy can measure the rate of ATP generated from phosphocreatine (PCr) via creatine kinase (CK) in the human heart. Recently, the triple-repetition time ST (TRiST) method was introduced to measure the CK pseudo-first-order rate constant kf in three acquisitions. In TRiST, the longitudinal relaxation time of PCr while γ-ATP is saturated, T1`, is measured for each subject, but suffers from low SNR because the PCr signal is reduced due to exchange with saturated γ-ATP, and the short repetition time of one of the acquisitions. Here, a two-repetition time ST (TwiST) method is presented. In TwiST, the acquisition with γ-ATP saturation and short repetition time is dropped. Instead of measuring T1`, an intrinsic relaxation time T1 for PCr, T1 (intrinsic), is assumed. The objective was to validate TwiST measurements of CK kinetics in healthy subjects and patients with heart failure (HF). METHODS Bloch equation simulations that included the effect of spillover irradiation on PCr were used to derive formulae for T1 (intrinsic) and kf measured by both TRiST and TwiST methods. Spillover was quantified from an unsaturated PCr measurement used in the current protocol for determining PCr and ATP concentrations. Cardiac TRiST and TwiST data were acquired at 3 T from 12 healthy and 17 HF patients. RESULTS Simulations showed that both kf measured by TwiST and T1 (intrinsic) require spill-over corrections. In human heart at 3 T, the spill-over corrected T1 (intrinsic) = 8.4 ± 1.4 s (mean ± SD) independent of study group. TwiST and TRiST kf measurements were the same, but TwiST was 9 min faster. Spill-over corrected TwiST kf was 0.33 ± 0.08 s(-1) vs. 0.20 ± 0.06 s(-1) in healthy vs HF hearts, respectively (p < 0.0001). CONCLUSION TwiST was validated against TRiST in the human heart at 3 T, generating the same results 9 min faster. TwiST detected significant reductions in CK kf in HF compared to healthy subjects, consistent with prior 1.5 T studies using different methodology.
Collapse
Affiliation(s)
- Michael Schär
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Refaat E Gabr
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - AbdEl-Monem M El-Sharkawy
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Systems and Biomedical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt.
| | - Angela Steinberg
- Cardiology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Paul A Bottomley
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Robert G Weiss
- Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cardiology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
13
|
Rink K, Berger MC, Korzowski A, Breithaupt M, Biller A, Bachert P, Nagel AM. Nuclear-Overhauser-enhanced MR imaging of (31)P-containing metabolites: multipoint-Dixon vs. frequency-selective excitation. Magn Reson Imaging 2015; 33:1281-1289. [PMID: 26248272 DOI: 10.1016/j.mri.2015.07.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 07/31/2015] [Indexed: 01/01/2023]
Abstract
The purpose of this study is to develop nuclear-Overhauser-enhanced (NOE) [(1)H]-(31)P magnetic resonance imaging (MRI) based on 3D fully-balanced steady-state free precession (fbSSFP). Therefore, two implementations of a 3D fbSSFP sequence are compared using frequency-selective excitation (FreqSel) and multipoint-Dixon (MP-Dixon). (31)P-containing model solutions and four healthy volunteers were examined at field strengths of B0=3T and 7T. Maps of the distribution of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine 5´-triphosphate (ATP) in the human calf were obtained with an isotropic resolution of 1.5cm (1.0cm) in an acquisition time of 5min (10min). NOE-pulses had the highest impact on the PCr acquisitions enhancing the signal up to (82 ± 13) % at 3T and up to (37 ± 9) % at 7T. An estimation of the level of PCr in muscle tissue from [(1)H]-(31)P MRI data yielded a mean value of (33 ± 8) mM. In conclusion, direct [(1)H]-(31)P imaging using FreqSel as well as MP-Dixon is possible in clinically feasible acquisition times. FreqSel should be preferred for measurements where only a single metabolite resonance is considered. MP-Dixon performs better in terms of SNR if a larger spectral width is of interest.
Collapse
Affiliation(s)
- Kristian Rink
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz C Berger
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Andreas Korzowski
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mathies Breithaupt
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Armin Biller
- Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Armin M Nagel
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| |
Collapse
|
14
|
Buehler T, Kreis R, Boesch C. Comparison of (31)P saturation and inversion magnetization transfer in human liver and skeletal muscle using a clinical MR system and surface coils. NMR IN BIOMEDICINE 2015; 28:188-199. [PMID: 25483778 DOI: 10.1002/nbm.3242] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 11/07/2014] [Accepted: 11/10/2014] [Indexed: 06/04/2023]
Abstract
(31)P MRS magnetization transfer ((31)P-MT) experiments allow the estimation of exchange rates of biochemical reactions, such as the creatine kinase equilibrium and adenosine triphosphate (ATP) synthesis. Although various (31)P-MT methods have been successfully used on isolated organs or animals, their application on humans in clinical scanners poses specific challenges. This study compared two major (31)P-MT methods on a clinical MR system using heteronuclear surface coils. Although saturation transfer (ST) is the most commonly used (31)P-MT method, sequences such as inversion transfer (IT) with short pulses might be better suited for the specific hardware and software limitations of a clinical scanner. In addition, small NMR-undetectable metabolite pools can transfer MT to NMR-visible pools during long saturation pulses, which is prevented with short pulses. (31)P-MT sequences were adapted for limited pulse length, for heteronuclear transmit-receive surface coils with inhomogeneous B1 , for the need for volume selection and for the inherently low signal-to-noise ratio (SNR) on a clinical 3-T MR system. The ST and IT sequences were applied to skeletal muscle and liver in 10 healthy volunteers. Monte-Carlo simulations were used to evaluate the behavior of the IT measurements with increasing imperfections. In skeletal muscle of the thigh, ATP synthesis resulted in forward reaction constants (k) of 0.074 ± 0.022 s(-1) (ST) and 0.137 ± 0.042 s(-1) (IT), whereas the creatine kinase reaction yielded 0.459 ± 0.089 s(-1) (IT). In the liver, ATP synthesis resulted in k = 0.267 ± 0.106 s(-1) (ST), whereas the IT experiment yielded no consistent results. ST results were close to literature values; however, the IT results were either much larger than the corresponding ST values and/or were widely scattered. To summarize, ST and IT experiments can both be implemented on a clinical body scanner with heteronuclear transmit-receive surface coils; however, ST results are much more robust against experimental imperfections than the current implementation of IT.
Collapse
Affiliation(s)
- Tania Buehler
- Departments of Clinical Research and Radiology, University of Bern, Switzerland
| | | | | |
Collapse
|
15
|
Ren J, Yang B, Sherry AD, Malloy CR. Exchange kinetics by inversion transfer: integrated analysis of the phosphorus metabolite kinetic exchanges in resting human skeletal muscle at 7 T. Magn Reson Med 2014; 73:1359-69. [PMID: 24733433 DOI: 10.1002/mrm.25256] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 03/06/2014] [Accepted: 03/26/2014] [Indexed: 01/06/2023]
Abstract
PURPOSE To develop an inversion pulse-based, chemical exchange saturation transfer-like method for detection of (31) P magnetization exchanges among all nuclear magnetic resonance visible metabolites suitable for providing an integrated kinetic analysis of phosphorus exchange reactions in vivo. METHODS The exchange kinetics by inversion transfer (EKIT) sequence includes application of a frequency-selective inversion pulse arrayed over the range of relevant (31) P frequencies, followed by a constant delay and a hard readout pulse. A series of EKIT spectra, each given by a plot of Z-magnetization for each metabolite of interest versus frequency of the inversion pulse, can be generated from this single data set. RESULTS EKIT spectra reflect chemical exchange due to known biochemical reactions, cross-relaxation effects, and relayed magnetization transfers due to both processes. The rate constants derived from EKIT data collected on resting human skeletal muscle were: ATP synthesis via ATP synthase (0.050 ± 0.016 s(-1) ), ATP synthesis via creatine kinase (0.264 ± 0.023 s(-1) ), and cross-relaxation between neighboring spin pairs within ATP (0.164 ± 0.022 s(-1) ). CONCLUSION EKIT provides a simple, alternative method to detect chemical exchange, cross relaxation, and relayed magnetization transfer effects in human skeletal muscle at 7 T.
Collapse
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
| | | | | | | |
Collapse
|
16
|
El-Sharkawy AMM, Gabr RE, Schär M, Weiss RG, Bottomley PA. Quantification of human high-energy phosphate metabolite concentrations at 3 T with partial volume and sensitivity corrections. NMR IN BIOMEDICINE 2013; 26:1363-71. [PMID: 23729378 PMCID: PMC5239719 DOI: 10.1002/nbm.2961] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/25/2013] [Accepted: 03/09/2013] [Indexed: 05/23/2023]
Abstract
Practical noninvasive methods for the measurement of absolute metabolite concentrations are key to the assessment of the depletion of myocardial metabolite pools which occurs with several cardiac diseases, including infarction and heart failure. Localized MRS offers unique noninvasive access to many metabolites, but is often confounded by nonuniform sensitivity and partial volume effects in the large, poorly defined voxels commonly used for the detection of low-concentration metabolites with surface coils. These problems are exacerbated at higher magnetic field strengths by greater radiofrequency (RF) field inhomogeneity and differences in RF penetration with heteronuclear concentration referencing. An example is the (31)P measurement of cardiac adenosine triphosphate (ATP) and phosphocreatine (PCr) concentrations, which, although central to cardiac energetics, have not been measured at field strengths above 1.5 T. Here, practical acquisition and analysis protocols are presented for the quantification of [PCr] and [ATP] with one-dimensionally resolved surface coil spectra and concentration referencing at 3 T. The effects of nonuniform sensitivity and partial tissue volumes are addressed at 3 T by the application of MRI-based three-dimensional sensitivity weighting and tissue segmentation. The method is validated in phantoms of different sizes and concentrations, and used to measure [PCr] and [ATP] in healthy subjects. In calf muscle (n = 8), [PCr] = 24.7 ± 3.4 and [ATP] = 5.7 ± 1.3 µmol/g wet weight, whereas, in heart (n = 18), [PCr] = 10.4 ± 1.5 and [ATP] = 6.0 ± 1.1 µmol/g wet weight (all mean ± SD), consistent with previous reports at lower fields. The method enables, for the first time, the efficient, semi-automated quantification of high-energy phosphate metabolites in humans at 3 T with nonuniform excitation and detection.
Collapse
Affiliation(s)
- Abdel-Monem M El-Sharkawy
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | | | | |
Collapse
|
17
|
Rodgers CT, Clarke WT, Snyder C, Vaughan JT, Neubauer S, Robson MD. Human cardiac 31P magnetic resonance spectroscopy at 7 Tesla. Magn Reson Med 2013; 72:304-15. [PMID: 24006267 PMCID: PMC4106879 DOI: 10.1002/mrm.24922] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 07/22/2013] [Accepted: 07/23/2013] [Indexed: 01/02/2023]
Abstract
Purpose Phosphorus magnetic resonance spectroscopy (31P-MRS) affords unique insight into cardiac energetics but has a low intrinsic signal-to-noise ratio (SNR) in humans. Theory predicts an increased 31P-MRS SNR at 7T, offering exciting possibilities to better investigate cardiac metabolism. We therefore compare the performance of human cardiac 31P-MRS at 7T to 3T, and measure T1s for 31P metabolites at 7T. Methods Matched 31P-MRS data were acquired at 3T and 7T, on nine normal volunteers. A novel Look-Locker CSI acquisition and fitting approach was used to measure T1s on six normal volunteers. Results T1s in the heart at 7T were: phosphocreatine (PCr) 3.05 ± 0.41s, γ-ATP 1.82 ± 0.09s, α-ATP 1.39 ± 0.09s, β-ATP 1.02 ± 0.17s and 2,3-DPG (2,3-diphosphoglycerate) 3.05 ± 0.41s (N = 6). In the field comparison (N = 9), PCr SNR increased 2.8× at 7T relative to 3T, the Cramer-Ráo uncertainty (CRLB) in PCr concentration decreased 2.4×, the mean CRLB in PCr/ATP decreased 2.7× and the PCr/ATP SD decreased 2×. Conclusion Cardiac 31P-MRS at 7T has higher SNR and the spectra can be quantified more precisely than at 3T. Cardiac 31P T1s are shorter at 7T than at 3T. We predict that 7T will become the field strength of choice for cardiac 31P-MRS. Magn Reson Med 72:304–315, 2014. © 2013 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance. 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.
Collapse
Affiliation(s)
- Christopher T Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
- * Correspondence to: Christopher T. Rodgers, D.Phil., Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford, OX3 9DU United Kingdom. E-mail:
| | - William T Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Carl Snyder
- Center for Magnetic Resonance Research, University of Minnesota2021 Sixth Street SE, Minneapolis, Minnesota, USA.
| | - J Thomas Vaughan
- Center for Magnetic Resonance Research, University of Minnesota2021 Sixth Street SE, Minneapolis, Minnesota, USA.
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
| |
Collapse
|
18
|
Noninvasive monitoring of training induced muscle adaptation with 31P-MRS: fibre type shifts correlate with metabolic changes. BIOMED RESEARCH INTERNATIONAL 2013; 2013:417901. [PMID: 23998123 PMCID: PMC3749530 DOI: 10.1155/2013/417901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/02/2013] [Accepted: 06/11/2013] [Indexed: 11/23/2022]
Abstract
Purpose. To evaluate training induced metabolic changes noninvasively with 31P magnetic resonance spectroscopy (31P-MRS) for measuring muscle fibre type adaptation.
Methods. Eleven volunteers underwent a 24-week training, consisting of speed-strength, endurance, and detraining (each 8 weeks). Prior to and following each training period, needle biopsies and 31P-MRS of the resting gastrocnemius muscle were performed. Fibre type distribution was analyzed histologically and tested for correlation with the ratios of high energy phosphates ([PCr]/[Pi], [PCr]/[βATP] and [PCr + Pi]/[βATP]). The correlation between the changes of the 31P-MRS parameters during training and the resulting changes in fibre composition were also analysed. Results. We observed an increased type-II-fibre proportion after speed-strength and detraining. After endurance training the percentage of fast-twitch fibres was reduced. The progression of the [PCr]/[Pi]-ratio was similar to that of the fast-twitch fibres during the training. We found a correlation between the type-II-fibre proportion and [PCr]/[Pi] (r = 0.70, P < 0.01) or [PCr]/[βATP] (r = 0.69, P < 0.01); the correlations between its changes (delta) and the fibre-shift were significant as well (delta[PCr]/[Pi] r = 0.66, delta[PCr]/[βATP] r = 0.55, P < 0.01). Conclusion. Shifts in fibre type composition and high energy phosphate metabolite content covary in human gastrocnemius muscle. Therefore 31P-MRS might be a feasible method for noninvasive monitoring of exercise-induced fibre type transformation.
Collapse
|
19
|
Bredella MA, Gerweck AV, Lin E, Landa MG, Torriani M, Schoenfeld DA, Hemphill LC, Miller KK. Effects of GH on body composition and cardiovascular risk markers in young men with abdominal obesity. J Clin Endocrinol Metab 2013; 98:3864-72. [PMID: 23824419 PMCID: PMC3763970 DOI: 10.1210/jc.2013-2063] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Visceral adiposity is associated with increased cardiometabolic risk and decreased GH secretion. OBJECTIVE Our objective was to determine the effects of GH administration in abdominally obese young men on body composition, including liver fat, mitochondrial function, and cardiovascular (CV) risk markers. DESIGN AND PARTICIPANTS This was a 6-month, randomized, double-blind, placebo-controlled study with 62 abdominally obese men (IGF-1 below the mean, no exclusion based on GH level), 21 to 45 years of age. MAIN OUTCOME MEASURES We evaluated abdominal fat depots, thigh muscle and fat (computed tomography), fat and lean mass (dual-energy x-ray absorptiometry), intramyocellular and intrahepatic lipids (proton magnetic resonance spectroscopy), mitochondrial function (dynamic phosphorous magnetic resonance spectroscopy), CV risk markers, carotid intimal-medial thickness, and endothelial function. RESULTS GH administration resulted in a mean IGF-1 SD score increase from -1.9 ± 0.08 to -0.2 ± 0.3 in the GH group and a decrease in visceral adipose tissue (VAT), VAT/sc adipose tissue, trunk/extremity fat, intrahepatic lipids, high-sensitivity C-reactive protein and apolipoprotein B/low-density lipoprotein vs placebo after controlling for the increase in weight observed in both groups. There were inverse associations between change in IGF-1 levels and change in VAT, VAT/sc adipose tissue, trunk fat, trunk/extremity fat, high-sensitivity C-reactive protein, and apolipoprotein B. Mitochondrial function improved in the GH group compared with placebo after controlling for change in glucose. There was no change in thigh fat, muscle mass, intramyocellular lipids, cholesterol, fibrinogen, intimal-medial thickness, or endothelial function. There was no increase in fasting glucose or hemoglobin A1c in the GH vs placebo group, although glucose during the 2-hour oral glucose tolerance test increased slightly. CONCLUSION GH replacement in abdominally obese men improves body composition, including liver fat, mitochondrial function, and markers of CV risk. Although fasting glucose was unchanged, a slight increase in 2-hour glucose during an oral glucose tolerance test was noted.
Collapse
Affiliation(s)
- Miriam A Bredella
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Parasoglou P, Xia D, Chang G, Regatte RR. 3D-mapping of phosphocreatine concentration in the human calf muscle at 7 T: comparison to 3 T. Magn Reson Med 2013; 70:1619-25. [PMID: 23390003 DOI: 10.1002/mrm.24616] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/27/2012] [Accepted: 12/05/2012] [Indexed: 01/09/2023]
Abstract
PURPOSE The development and implementation of a spectrally selective 3D-Turbo Spin Echo sequence for quantitative mapping of phosphocreatine (PCr) concentration in different muscles of the lower leg of healthy volunteers both at 3 T and 7 T. METHODS Nine healthy volunteers were recruited, all of whom where scanned at 3 T and 7 T. Three dimensional PCr concentration maps were obtained after images were corrected for B1 inhomogeneities, T1 relaxation weighting, and partial volume of fatty tissue in the muscles. Two volunteers performed plantar flexions inside the magnet, and the oxidative capacity of their muscles was estimated. RESULTS Three dimensional PCr concentration maps were obtained, with full muscle coverage and nominal voxel size of 0.52 mL at both fields. At 7 T a 2.7-fold increase of signal-to-noise ratio was achieved compared to 3 T. CONCLUSION Imaging (31) P metabolites at 7 T allowed for significant increase in signal to noise ratio compared to imaging at 3 T, while quantification of the PCr concentration remained unaffected. The importance of such an increase in signal-to-noise ratio is 2-fold, first higher resolution images with reduced partial volume effects can be acquired, and second multiple measurements such as dynamic imaging of PCr post-exercise, (31) P magnetization transfer, or other (1) H measurements, can be acquired in a single imaging session.
Collapse
Affiliation(s)
- Prodromos Parasoglou
- Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, New York, USA
| | | | | | | |
Collapse
|
21
|
Parasoglou P, Xia D, Regatte RR. Spectrally selective 3D TSE imaging of phosphocreatine in the human calf muscle at 3 T. Magn Reson Med 2012; 69:812-7. [PMID: 22499078 DOI: 10.1002/mrm.24288] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/14/2012] [Accepted: 03/16/2012] [Indexed: 12/29/2022]
Abstract
Quantitative information about concentrations of several metabolites in human skeletal muscle can be obtained through localized (31)P magnetic resonance spectroscopy methods. However, these methods have shortcomings: long acquisition times, limited volume coverage, and coarse resolution. Significantly higher spatial and temporal resolution of imaging of single metabolites can be achieved through spectrally selective three-dimensional imaging methods. This study reports the implementation of a three-dimensional spectrally selective turbo spin-echo sequence, on a 3T clinical system, to map the concentration of phosphocreatine in the human calf muscle with significantly increased spatial resolution and in a clinically feasible scan time. Absolute phosphocreatine quantification was performed with the use of external phantoms after relaxation and flip angle correction of the turbo spin-echo voxel signal. The mean ± standard deviation of the phosphocreatine concentration measured in five healthy volunteers was 29.4 ± 2.5 mM with signal-to-noise ratio of 14:1 and voxel size of 0.52 mL.
Collapse
Affiliation(s)
- Prodromos Parasoglou
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, New York 10016, USA.
| | | | | |
Collapse
|
22
|
Meyerspeer M, Robinson S, Nabuurs CI, Scheenen T, Schoisengeier A, Unger E, Kemp GJ, Moser E. Comparing localized and nonlocalized dynamic 31P magnetic resonance spectroscopy in exercising muscle at 7 T. Magn Reson Med 2012; 68:1713-23. [PMID: 22334374 PMCID: PMC3378633 DOI: 10.1002/mrm.24205] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/11/2012] [Accepted: 01/19/2012] [Indexed: 12/31/2022]
Abstract
By improving spatial and anatomical specificity, localized spectroscopy can enhance the power and accuracy of the quantitative analysis of cellular metabolism and bioenergetics. Localized and nonlocalized dynamic (31)P magnetic resonance spectroscopy using a surface coil was compared during aerobic exercise and recovery of human calf muscle. For localization, a short echo time single-voxel magnetic resonance spectroscopy sequence with adiabatic refocusing (semi-LASER) was applied, enabling the quantification of phosphocreatine, inorganic phosphate, and pH value in a single muscle (medial gastrocnemius) in single shots (T(R) = 6 s). All measurements were performed in a 7 T whole body scanner with a nonmagnetic ergometer. From a series of equal exercise bouts we conclude that: (a) with localization, measured phosphocreatine declines in exercise to a lower value (79 ± 7% cf. 53 ± 10%, P = 0.002), (b) phosphocreatine recovery shows shorter half time (t(1/2) = 34 ± 7 s cf. t(1/2) = 42 ± 7 s, nonsignificant) and initial postexercise phosphocreatine resynthesis rate is significantly higher (32 ± 5 mM/min cf. 17 ± 4 mM/min, P = 0.001) and (c) in contrast to nonlocalized (31)P magnetic resonance spectroscopy, no splitting of the inorganic phosphate peak is observed during exercise or recovery, just an increase in line width during exercise. This confirms the absence of contaminating signals originating from weaker-exercising muscle, while an observed inorganic phosphate line broadening most probably reflects variations across fibers in a single muscle.
Collapse
Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Ghomi RH, Bredella MA, Thomas BJ, Miller KK, Torriani M. Modular MR-compatible lower leg exercise device for whole-body scanners. Skeletal Radiol 2011; 40:1349-54. [PMID: 21271342 PMCID: PMC3667703 DOI: 10.1007/s00256-011-1098-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 01/04/2011] [Accepted: 01/06/2011] [Indexed: 02/02/2023]
Abstract
PURPOSE To develop a modular MR-compatible lower leg exercise device for muscle testing using a clinical 3 T MR scanner. MATERIALS AND METHODS An exercise device to provide isotonic resistance to plantar- or dorsiflexion was constructed from nonferrous materials and designed for easy setup and use in a clinical environment. Validation tests were performed during dynamic MR acquisitions. For this purpose, the device was tested on the posterior lower leg musculature of five subjects during 3 min of exercise at 30% of maximum voluntary plantarflexion during 31-phosphorus MR spectroscopy ((31)P-MRS). Measures of muscle phosphocreatine (PCr), inorganic phosphate (Pi), and pH were obtained before, during, and after the exercise protocol. RESULTS At the end of exercise regimen, muscle PCr showed a 28% decrease from resting levels (to 21.8 ± 3.9 from 30.4 ± 3.0 mM) and the average PCr recovery rate was 35.3 ± 8.3 s. Muscle Pi concentrations increased 123% (to 14.6 ± 4.7 from 6.5 ± 3.3 mM) and pH decreased 1.5% (to 7.06 ± 0.14 from 7.17 ± 0.07) from resting levels. CONCLUSION The described MR-compatible lower leg exercise was an effective tool for data acquisition during dynamic MR acquisitions of the calf muscles. The modular design allows for adaptation to other whole-body MR scanners and incorporation of custom-built mechanical or electronic interfaces and can be used for any MR protocol requiring dynamic evaluation of calf muscles.
Collapse
Affiliation(s)
- Reza Hosseini Ghomi
- Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6048, Boston, MA 02114, USA
| | - Miriam A. Bredella
- Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6048, Boston, MA 02114, USA
| | - Bijoy J. Thomas
- Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6048, Boston, MA 02114, USA
| | - Karen K. Miller
- Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Martin Torriani
- Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, YAW 6048, Boston, MA 02114, USA
| |
Collapse
|
24
|
Meyerspeer M, Scheenen T, Schmid AI, Mandl T, Unger E, Moser E. Semi-LASER localized dynamic 31P magnetic resonance spectroscopy in exercising muscle at ultra-high magnetic field. Magn Reson Med 2011; 65:1207-15. [PMID: 21384422 PMCID: PMC3272370 DOI: 10.1002/mrm.22730] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 09/18/2010] [Accepted: 10/25/2010] [Indexed: 11/10/2022]
Abstract
Magnetic resonance spectroscopy (MRS) can benefit from increased signal-to-noise ratio (SNR) of high magnetic fields. In this work, the SNR gain of dynamic 31P MRS at 7 T was invested in temporal and spatial resolution. Using conventional slice selective excitation combined with localization by adiabatic selective refocusing (semi-LASER) with short echo time (TE = 23 ms), phosphocreatine quantification in a 38 mL voxel inside a single exercising muscle becomes possible from single acquisitions, with SNR = 42 ± 4 in resting human medial gastrocnemius. The method was used to quantify the phosphocreatine time course during 5 min of plantar flexion exercise and recovery with a temporal resolution of 6 s (the chosen repetition time for moderate T1 saturation). Quantification of inorganic phosphate and pH required accumulation of consecutively acquired spectra when (resting) Pi concentrations were low. The localization performance was excellent while keeping the chemical shift displacement acceptably small. The SNR and spectral line widths with and without localization were compared between 3 T and 7 T systems in phantoms and in vivo. The results demonstrate that increased sensitivity of ultra-high field can be used to dynamically acquire metabolic information from a clearly defined region in a single exercising muscle while reaching a temporal resolution previously available with MRS in non-localizing studies only. The method may improve the interpretation of dynamic muscle MRS data. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.
Collapse
Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Wien, Austria
| | | | | | | | | | | |
Collapse
|
25
|
Kacerovsky M, Brehm A, Chmelik M, Schmid AI, Szendroedi J, Kacerovsky-Bielesz G, Nowotny P, Lettner A, Wolzt M, Jones JG, Roden M. Impaired insulin stimulation of muscular ATP production in patients with type 1 diabetes. J Intern Med 2011; 269:189-99. [PMID: 21205021 DOI: 10.1111/j.1365-2796.2010.02298.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE in type 2 diabetic patients and their first-degree relatives, insulin resistance (IR) is associated with impairment of insulin-stimulated myocellular glucose-6-phosphate (g6p) and unidirectional flux through ATP synthase (fATP), suggesting the presence of inherited abnormal mitochondrial oxidative fitness. We hypothesized that patients with long-standing type 1 diabetes may also exhibit insulin resistance as well as lower fATP. DESIGN this single-centre trial was registered at ClinicalTrials.gov (NCT00481598). SUBJECTS we included eight nonobese type 1 diabetic patients (mean diabetes duration: 17 years) with near-target glycaemic control [haemoglobin A1c (HbA1c): 6.8 ± 0.4%] during treatment with continuous subcutaneous insulin infusion pumps and eight healthy volunteers (HbA1c: 5.4 ± 0.2%) of comparable age, body mass and level of physical activity. OUTCOME MEASURES myocellular fATP, g6p and intramyocellular lipid content (IMCL) were measured with (1) H/(31) P magnetic resonance spectroscopy during fasting and hyperinsulinaemic-euglycaemic clamp tests. RESULTS fasting fATP, g6p and IMCL did not differ between groups. During stimulation by insulin, type 1 diabetic patients exhibited approximately 50% (P < 0.001) lower whole-body glucose disposal along with approximately 42% (P = 0.003) lower intramyocellular g6p and approximately25% (P = 0.024) lower fATP. Insulin-stimulated fATP correlated positively with whole-body insulin sensitivity (R = 0.706, P = 0.002) and negatively with HbA1c (R = -0.675, P = 0.004). CONCLUSIONS despite documented near-target glycaemic control for 1 year, nonobese patients with long-standing type 1 diabetes can exhibit insulin resistance. This associates with lower insulin-stimulated flux through muscular ATP synthase which could result from glucose toxicity.
Collapse
Affiliation(s)
- M Kacerovsky
- Karl-Landsteiner Institute for Endocrinology and Metabolism, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Schär M, El-Sharkawy AMM, Weiss RG, Bottomley PA. Triple repetition time saturation transfer (TRiST) 31P spectroscopy for measuring human creatine kinase reaction kinetics. Magn Reson Med 2010; 63:1493-501. [PMID: 20512852 DOI: 10.1002/mrm.22347] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Human cardiac phosphorus MR saturation transfer experiments to quantify creatine kinase forward rate constants (k(f)) have previously been performed at 1.5 T. Such experiments could benefit from increased signal-to-noise ratio (SNR) and spectral resolution at 3 T. At 1.5 T, the four-angle saturation transfer method was applied with low-angle adiabatic pulses and surface coils. However, low-angle adiabatic pulses are potentially problematic above 1.5 T due to bandwidth limitations, power requirements, power deposition, and intrapulse spin-spin relaxation. For localized metabolite spin-lattice relaxation time (T(1)) measurements, a dual repetition time approach with adiabatic half-passage pulses was recently introduced to solve these problems at 3 T. Because the saturation transfer experiment requires a T(1) measurement performed while one reacting moiety is saturated, we adapt the dual repetition time approach to measure k(f) using a triple repetition time saturation transfer (TRiST) method. A new pulsed saturation scheme with reduced sensitivity to static magnetic field inhomogeneity and compatibility with cardiac triggering is also presented. TRiST measurements of k(f) are validated in human calf muscle against conventional saturation transfer and found to agree within 3%. The first 3-T TRiST measurements of creatine kinase k(f) in the human calf (n = 6), chest muscle, and heart (n = 8) are 0.26 +/- 0.04 s(-1), 0.23 +/- 0.03 s(-1), and 0.32 +/- 0.07 s(-1), respectively, consistent with prior 1.5 T values.
Collapse
Affiliation(s)
- Michael Schär
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
| | | | | | | |
Collapse
|
27
|
Kan HE, Klomp DWJ, Wohlgemuth M, van Loosbroek-Wagemans I, van Engelen BGM, Padberg GW, Heerschap A. Only fat infiltrated muscles in resting lower leg of FSHD patients show disturbed energy metabolism. NMR IN BIOMEDICINE 2010; 23:563-568. [PMID: 20175146 DOI: 10.1002/nbm.1494] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is characterized by asymmetric dysfunctioning of individual muscles. Currently, it is unknown why specific muscles are affected before others and more particularly what pathophysiology is causing this differential progression. The aim of our study was to use a combination of (31)P magnetic resonance spectroscopic imaging (MRSI) and T1-weighted MRI to uncover metabolic differences in fat infiltrated and not fat infiltrated muscles in patients with FSHD. T1-weighted images and 3D (31)P MRSI were obtained from the calf muscles of nine patients with diagnosed FSHD and nine healthy age and sex matched volunteers. Muscles of patients were classified as fat infiltrated (PFM) and non fat-infiltrated (PNM) based on visual assessment of the MR images. Ratios of phosphocreatine (PCr), phosphodiesters (PDE) and inorganic phosphate (Pi) over ATP and tissue pH were compared between PFM and PNM and the same muscles in healthy volunteers. Of all patients, seven showed moderate to severe fatty infiltration in one or more muscles. In these muscles, decreases in PCr/ATP and increases in tissue pH were observed compared to the same muscles in healthy volunteers. Interestingly, these differences were absent in the PNM group. Our data show that differences in metabolite ratios and tissue pH in skeletal muscle between healthy volunteers and patients with FSHD appear to be specific for fat infiltrated muscles. Normal appearing muscles on T1 weighted images of patients showed normal phosphoryl metabolism, which suggests that in FSHD disease progression is truly muscle specific.
Collapse
Affiliation(s)
- H E Kan
- Department of Radiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
28
|
Moser E, Meyerspeer M, Fischmeister FPS, Grabner G, Bauer H, Trattnig S. Windows on the human body--in vivo high-field magnetic resonance research and applications in medicine and psychology. SENSORS (BASEL, SWITZERLAND) 2010; 10:5724-57. [PMID: 22219684 PMCID: PMC3247729 DOI: 10.3390/s100605724] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 04/02/2010] [Accepted: 05/17/2010] [Indexed: 12/30/2022]
Abstract
Analogous to the evolution of biological sensor-systems, the progress in "medical sensor-systems", i.e., diagnostic procedures, is paradigmatically described. Outstanding highlights of this progress are magnetic resonance imaging (MRI) and spectroscopy (MRS), which enable non-invasive, in vivo acquisition of morphological, functional, and metabolic information from the human body with unsurpassed quality. Recent achievements in high and ultra-high field MR (at 3 and 7 Tesla) are described, and representative research applications in Medicine and Psychology in Austria are discussed. Finally, an overview of current and prospective research in multi-modal imaging, potential clinical applications, as well as current limitations and challenges is given.
Collapse
Affiliation(s)
- Ewald Moser
- MR Center of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria; E-Mails: (M.M.); (F.Ph.S.F.); (G.G.); (S.T.)
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
- Department of Diagnostic Radiology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Martin Meyerspeer
- MR Center of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria; E-Mails: (M.M.); (F.Ph.S.F.); (G.G.); (S.T.)
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Florian Ph. S. Fischmeister
- MR Center of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria; E-Mails: (M.M.); (F.Ph.S.F.); (G.G.); (S.T.)
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
- Brain Research Lab, Department of Clinical, Biological and Differential Psychology, Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010 Vienna, Austria; E-Mail:
| | - Günther Grabner
- MR Center of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria; E-Mails: (M.M.); (F.Ph.S.F.); (G.G.); (S.T.)
- Department of Diagnostic Radiology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Herbert Bauer
- Brain Research Lab, Department of Clinical, Biological and Differential Psychology, Faculty of Psychology, University of Vienna, Liebiggasse 5, A-1010 Vienna, Austria; E-Mail:
| | - Siegfried Trattnig
- MR Center of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria; E-Mails: (M.M.); (F.Ph.S.F.); (G.G.); (S.T.)
- Department of Diagnostic Radiology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| |
Collapse
|
29
|
Moser E. Ultra-high-field magnetic resonance: Why and when? World J Radiol 2010; 2:37-40. [PMID: 21160738 PMCID: PMC2999312 DOI: 10.4329/wjr.v2.i1.37] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/10/2010] [Accepted: 01/13/2010] [Indexed: 02/06/2023] Open
Abstract
This paper briefly summarizes the development of magnetic resonance imaging and spectroscopy in medicine. Aspects of magnetic resonancephysics and -technology relevant at ultra-high magnetic fields as well as current limitations are highlighted. Based on the first promising studies, potential clinical applications at 7 Tesla are suggested. Other aims are to stimulate awareness of the potential of ultra-high field magnetic resonance and to stimulate active participation in much needed basic or clinical research at 7 Tesla or higher.
Collapse
|
30
|
Bogner W, Chmelik M, Schmid AI, Moser E, Trattnig S, Gruber S. Assessment of (31)P relaxation times in the human calf muscle: a comparison between 3 T and 7 T in vivo. Magn Reson Med 2009; 62:574-82. [PMID: 19526487 DOI: 10.1002/mrm.22057] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Phosphorus ((31)P) T(1) and T(2) relaxation times in the resting human calf muscle were assessed by interleaved, surface coil localized inversion recovery and frequency-selective spin-echo at 3 and 7 T. The obtained T(1) (mean +/- SD) decreased significantly (P < 0.05) from 3 to 7 T for phosphomonoesters (PME) (8.1 +/- 1.7 s to 3.1 +/- 0.9 s), phosphodiesters (PDE) (8.6 +/- 1.2 s to 6.0 +/- 1.1 s), phosphocreatine (PCr) (6.7 +/- 0.4 s to 4.0 +/- 0.2 s), gamma-NTP (nucleotide triphosphate) (5.5 +/- 0.4 s to 3.3 +/- 0.2 s), alpha-NTP (3.4 +/- 0.3 s to 1.8 +/- 0.1 s), and beta-NTP (3.9 +/- 0.4 s to 1.8 +/- 0.1 s), but not for inorganic phosphate (Pi) (6.9 +/- 0.6 s to 6.3 +/- 1.0 s). The decrease in T(2) was significant for Pi (153 +/- 9 ms to 109 +/- 17 ms), PDE (414 +/- 128 ms to 314 +/- 35 ms), PCr (354 +/- 16 ms to 217 +/- 14 ms), and gamma-NTP (61.9 +/- 8.6 ms to 29.0 +/- 3.3 ms). This decrease in T(1) with increasing field strength of up to 62% can be explained by the increasing influence of chemical shift anisotropy on relaxation mechanisms and may allow shorter measurements at higher field strengths or up to 62% additional signal-to-noise ratio (SNR) per unit time. The fully relaxed SNR increased by +96%, while the linewidth increased from 6.5 +/- 1.2 Hz to 11.2 +/- 1.9 Hz or +72%. At 7 T (31)P-MRS in the human calf muscle offers more than twice as much SNR per unit time in reduced measurement time compared to 3 T. This will facilitate in vivo (31)P-MRS of the human muscle at 7 T.
Collapse
Affiliation(s)
- W Bogner
- Department of Radiology, Medical University Vienna, Vienna, Austria
| | | | | | | | | | | |
Collapse
|
31
|
El-Sharkawy AM, Schär M, Ouwerkerk R, Weiss RG, Bottomley PA. Quantitative cardiac 31P spectroscopy at 3 Tesla using adiabatic pulses. Magn Reson Med 2009; 61:785-95. [PMID: 19195018 DOI: 10.1002/mrm.21867] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Cardiac phosphorus magnetic resonance spectroscopy (MRS) with surface coils promises better quantification at 3 Tesla (T) from improved signal-to-noise ratios and spectral resolution compared with 1.5 T. However, Bloch equation and field analyses at 3T show that for efficient quantitative MRS protocols using small-angle adiabatic (BIR4/BIRP) pulses the excitation-field is limited by radiofrequency (RF) power requirements and power deposition. When BIR4/BIRP pulse duration is increased to reduce power levels, T2-decay can introduce flip-angle dependent errors in the steady-state magnetization, causing errors in saturation corrections for metabolite quantification and in T1s measured by varying the flip-angle. A new dual-repetition-time (2TR) T1 method using frequency-sign-cycled adiabatic-half-passage pulses is introduced to alleviate power requirements, and avoid the problem related to T2 relaxation during the RF pulse. The 2TR method is validated against inversion-recovery in phantoms using a practical transmit/receive coil set designed for phosphorus MRS of the heart at depths of 9-10 cm with 4 kW of pulse power. The T1s of phosphocreatine (PCr) and adenosine triphosphate (gamma-ATP) in the calf-muscle (n=9) at 3 T are 6.8+/-0.3 s and 5.4+/-0.6 s, respectively. For heart (n=10) the values are 5.8+/-0.5 s (PCr) and 3.1+/-0.6 s (gamma-ATP). The 2TR protocol measurements agreed with those obtained by conventional methods to within 10%.
Collapse
Affiliation(s)
- AbdEl-Monem El-Sharkawy
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | | | | | | | | |
Collapse
|
32
|
Kemp GJ, Meyerspeer M, Moser E. Absolute quantification of phosphorus metabolite concentrations in human muscle in vivo by 31P MRS: a quantitative review. NMR IN BIOMEDICINE 2007; 20:555-65. [PMID: 17628042 DOI: 10.1002/nbm.1192] [Citation(s) in RCA: 215] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
31P MRS offers a unique view of muscle metabolism in vivo, but correct quantification is important. Inter-study correlation of estimates of [Pi] and [phosphocreatine (PCr)] in a number of published studies suggest that the main technical problem in calibrated 31P MRS studies is the measurement of PCr and Pi signal intensities, rather than absolute quantification of [ATP]. For comparison, we discuss the few published biopsy studies of calf muscle and a selection of the many studies of quadriceps muscle. The ATP concentration is close to the value that we obtained in calf muscle in our own study, presented here, on four healthy subjects, by localised 31P MRS using a surface coil incorporating an internal reference and calibrated using an external phantom. However, the freeze-clamp biopsy PCr concentration is approximately 20% lower than the value obtained by 31P MRS, consistent with PCr breakdown by creatine kinase during freezing. Finally, we illustrate some consequences of uncertainty in resting [PCr] for analysis of mitochondrial function from PCr kinetics using a published 31P MRS study of exercise and recovery: the lower the assumed resting [PCr], the lower the absolute rate of oxidative ATP synthesis estimated from the PCr resynthesis rate; in addition, the lower the assumed resting [PCr], or the higher the assumed [total creatine], the higher the apparent resting [ADP], and therefore the more sigmoid the relationship between the rate of oxidative ATP synthesis and [ADP]. Correct quantification of resting metabolite concentrations is crucially important for this sort of analysis. Our own results ([PCr] = 33 +/- 2 mM, [Pi] = 4.5 +/- 0.2 mM, and [ATP] = 8.2 +/- 0.4 mM; mean +/- SEM) are close to the overall mean values of the 10 published studies on calf muscle by 'calibrated' 31P MRS (as in the present work), and of [PCr] and [Pi] in a representative selection of 'uncalibrated' 31P MRS studies (i.e. from measured PCr/ATP and Pi/ATP ratios, assuming a literature value for [ATP]).
Collapse
Affiliation(s)
- Graham J Kemp
- Division of Metabolic and Cellular Medicine, Faculty of Medicine, University of Liverpool, Liverpool, UK
| | | | | |
Collapse
|
33
|
Meyerspeer M, Kemp GJ, Mlynárik V, Krššák M, Szendroedi J, Nowotny P, Roden M, Moser E. Direct noninvasive quantification of lactate and high energy phosphates simultaneously in exercising human skeletal muscle by localized magnetic resonance spectroscopy. Magn Reson Med 2007; 57:654-60. [PMID: 17390348 PMCID: PMC4876926 DOI: 10.1002/mrm.21188] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A novel method based on interleaved localized 31P- and 1H MRS is presented, by which lactate accumulation and the accompanying changes in high energy phosphates in human skeletal muscle can be monitored simultaneously during exercise and recovery. Lactate is quantified using a localized double quantum filter suppressing the abundant lipid signals while taking into account orientation dependent signal modulations. Lactate concentration after ischemic exercise directly quantified by DQF 1H spectroscopy was 24 +/- 3 mmol/L cell water, while 22 +/- 3 mmol/L was expected on the basis of 31P MRS acquired simultaneously. Lactate concentration in a sample of porcine meat was estimated to be 40 +/- 7 mmol/L by means of DQF quantitation, versus 39 +/- 5 mmol/L by biochemical methods. Excellent agreement is shown between lactate concentrations measured noninvasively by 1H MRS, measured biochemically ex vivo, and inferred indirectly in vivo from changes in pH, P(i), and PCr as obtained from 31P MRS data.
Collapse
Affiliation(s)
- Martin Meyerspeer
- MR Centre of Excellence, Medical University of Vienna, Austria
- Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
| | - Graham J. Kemp
- Division of Metabolic and Cellular Medicine, School of Clinical Science, Faculty of Medicine, University of Liverpool, United Kingdom
| | - Vladimir Mlynárik
- MR Centre of Excellence, Medical University of Vienna, Austria
- Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
| | - Martin Krššák
- MR Centre of Excellence, Medical University of Vienna, Austria
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
| | - Julia Szendroedi
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
| | - Peter Nowotny
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
| | - Michael Roden
- Department of Internal Medicine III, Division of Endocrinology and Metabolism, Medical University of Vienna, Austria
- Karl-Landsteiner Institute of Endocrinology and Metabolism, Vienna, Austria
- 1st Med. Department, Hanusch Hospital Vienna, Austria
| | - Ewald Moser
- MR Centre of Excellence, Medical University of Vienna, Austria
- Center for Biomedical Engineering and Physics, Medical University of Vienna, Austria
- Department of Diagnostic Radiology, Medical University of Vienna, Austria
- Correspondence to: Ewald Moser, MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria.
| |
Collapse
|
34
|
Cettolo V, Piorico C, Francescato MP. T(1) measurement of (31)P metabolites at rest and during steady-state dynamic exercise using a clinical nuclear magnetic resonance scanner. Magn Reson Med 2006; 55:498-505. [PMID: 16450372 DOI: 10.1002/mrm.20803] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This article illustrates some problems and possible solutions to determine the apparent spin-lattice relaxation time (T(1)) of the muscular (31)P metabolites at rest and during dynamic steady-state exercise using a clinical 1.5 T NMR scanner and a surface coil. T(1) was first estimated on a phosphates solution (phantom) using four different acquisition protocols, all based on the multiple-point "progressive saturation" method, and by fitting each data set with two different mathematical models. Subsequently, two of the four protocols and both models were used to estimate T(1) both at rest and during exercise on the calf muscles of 10 healthy volunteers. Experimental results obtained on the phantom showed that T(1) is greatly affected by the longest nominal explored repetition time (P<0.001) and by the mathematical model (P<0.001), ranging from 0.65+/-0.10 to 8.4+/-0.8 s. The two acquisition protocols applied on volunteers yielded significantly different T(1) (P<0.001), which were also rather different from the literature values for the same metabolites. Nevertheless, independently of the acquisition protocol and/or the fitting procedure, T(1) of all muscular phosphagens did not change statistically from rest to steady-state aerobic exercise.
Collapse
Affiliation(s)
- V Cettolo
- Dipartimento di Scienze e Tecnologie Biomediche and M.A.T.I. Centre of Excellence, Università degli Studi di Udine, Udine, Italy
| | | | | |
Collapse
|
35
|
Meyerspeer M, Krssák M, Kemp GJ, Roden M, Moser E. Dynamic interleaved 1H/31P STEAM MRS at 3 Tesla using a pneumatic force-controlled plantar flexion exercise rig. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2005; 18:257-62. [PMID: 16320091 PMCID: PMC4876922 DOI: 10.1007/s10334-005-0014-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 07/01/2005] [Accepted: 09/07/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To develop a measurement method for interleaved acquisition of 1H and 31 STEAM localised spectra of exercising human calf muscle. MATERIALS AND METHODS A non-magnetic exercise rig with a pneumatic piston and sensors for force and pedal angle was constructed to enable plantar flexion measured in the 3 T MR scanner, which holds the dual tuned (1H ,31P) surface coil used for signal transmission and reception. RESULTS (31) spectra acquired in interleaved mode benefit from higher Signal to noise ratio (factor of 1.34 +/-0.06 for PCr) compared to standard acquisition due to the Nuclear Overhauser effect and substantial PCr/P(i) changes during exercise can be observed in 31P spectra. 1H spectral quality is equal to that in single mode experiments and allows Cr2 changes to be monitored. CONCLUSION The feasibility of dynamic interleaved localised 1H and 31P spectroscopy during plantar flexion exercise has been demonstrated using a custom-built pneumatic system for muscle activation. This opens the possibility of studying the dynamics of metabolism with multi nuclear MRS in a single run.
Collapse
Affiliation(s)
- M Meyerspeer
- MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria
| | | | | | | | | |
Collapse
|