1
|
Sun C, Bauer CC, Hou J, Wright SM. Wideband receive-coil array design using high-impedance amplifiers for broadband decoupling. Magn Reson Med 2023; 90:2198-2210. [PMID: 37382188 DOI: 10.1002/mrm.29755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 04/17/2023] [Accepted: 05/21/2023] [Indexed: 06/30/2023]
Abstract
PURPOSE Multinuclear MRI/S is of increasing interest. Currently, most multinuclear receive array coils are constructed by nesting multiple single-tuned array coils or using switching elements to control the operating frequency, in which case more than one set of conventional isolation preamplifiers and associated decoupling circuits is required. These conventional configurations rapidly become complicated when greater numbers of channels or nuclei are needed. In this work, a novel coil decoupling mechanism is proposed to enable broadband decoupling for array coils with one set of preamplifiers. METHODS Instead of using conventional isolation preamplifiers, a high-input impedance preamplifier is proposed to create broadband decoupling of the array elements. A matching network consisting of a single inductor-capacitor-capacitor multi-tuned network and a wire-wound transformer was used to interface the surface coil to the high-impedance preamplifier. To validate the concept, the proposed configuration was compared to the conventional preamplifier decoupling configuration on both bench and scanner. RESULTS 2 The approach can provide more than 15dB decoupling over a range of 25MHz, covering the Larmor frequencies of 23 Na and 2 H at 4.7T. This multi-tuned prototype obtained 61% and 76% of the imaging SNR at 2 H and 23 Na respectively, 76 and 89% in a higher loading test phantom, when compared to the conventional single-tuned preamplifier decoupling configuration. CONCLUSION With the multinuclear array operation and decoupling achieved using only one layer of array coil and preamplifiers, this work provides a simple approach of building high element-count arrays to enable accelerated imaging or SNR improvement from multiple nuclei.
Collapse
Affiliation(s)
- Chenhao Sun
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA
| | - Courtney C Bauer
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Jue Hou
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Steven M Wright
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA
| |
Collapse
|
2
|
Gast LV, Baier LM, Meixner CR, Chaudry O, Engelke K, Uder M, Nagel AM, Heiss R. MRI of Potassium and Sodium Enables Comprehensive Analysis of Ion Perturbations in Skeletal Muscle Tissue After Eccentric Exercise. Invest Radiol 2023; 58:265-272. [PMID: 36374200 PMCID: PMC9997635 DOI: 10.1097/rli.0000000000000931] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The aims were to investigate if potassium ( 39 K) magnetic resonance imaging (MRI) can be used to analyze changes in the apparent tissue potassium concentration (aTPC) in calf muscle tissue after eccentric exercise and in delayed-onset muscle soreness, and to compare these to corresponding changes in the apparent tissue sodium concentration (aTSC) measured with sodium ( 23 Na) MRI. MATERIALS AND METHODS Fourteen healthy subjects (7 female, 7 male; 25.0 ± 2.8 years) underwent 39 K and 23 Na MRI at a 7 T MR system, as well as 1 H MRI at a 3 T MR system. Magnetic resonance imaging data and blood samples were collected at baseline (t0), directly after performing eccentric exercise (t1) and 48 hours after exercise (t2). Self-reported muscle soreness was evaluated using a 10-cm visual analog scale for pain (0, no pain; 10, worst pain) at t0, t1, and t2. Quantification of aTPC/aTSC was performed after correcting the measured 39 K/ 23 Na signal intensities for partial volume and relaxation effects using 5 external reference phantoms. Edema volume and 1 H T 2 relaxation times were determined based on the 1 H MRI data. Participants were divided according to their increase in creatine kinase (CK) level into high (CK t2 ≥ 10·CK t0 ) and low CK (CK t2 < 10·CK t0 ) subjects. RESULTS Blood serum CK and edema volume were significantly increased 48 hours after exercise compared with baseline ( P < 0.001). Six participants showed a high increase in blood serum CK level at t2 relative to baseline, whereas 8 participants had only a low to moderate increase in blood serum CK. All participants reported increased muscle soreness both at rest and when climbing stairs at t1 (0.4 ± 0.7; 1.4 ± 1.2) and t2 (1.6 ± 1.4; 4.8 ± 1.9) compared with baseline (0 ± 0; 0 ± 0). Moreover, aTSC was increased at t1 in exercised muscles of all participants (increase by 57% ± 24% in high CK, 73% ± 33% in low CK subjects). Forty-eight hours after training, subjects with high increase in blood serum CK still showed highly increased aTSC (increase by 79% ± 57% compared with t0). In contrast, aTPC at t2 was elevated in exercised muscles of low CK subjects (increase by 19% ± 11% compared with t0), in which aTSC had returned to baseline or below. Overall, aTSC and aTPC showed inverse evolution, with changes in aTSC being approximately twice as high as in aTPC. CONCLUSIONS Our results showed that 39 K MRI is able to detect changes in muscular potassium concentrations caused by eccentric exercise. In combination with 23 Na MRI, this enables a more holistic analysis of tissue ion concentration changes.
Collapse
Affiliation(s)
| | | | | | - Oliver Chaudry
- Department of Medicine 3, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg
| | - Klaus Engelke
- Department of Medicine 3, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg
- Institute of Medical Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen
| | | | - Armin M. Nagel
- From the Institute of Radiology
- Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
| | | |
Collapse
|
3
|
Lopez Kolkovsky AL, Carlier PG, Marty B, Meyerspeer M. Interleaved and simultaneous multi-nuclear magnetic resonance in vivo. Review of principles, applications and potential. NMR IN BIOMEDICINE 2022; 35:e4735. [PMID: 35352440 PMCID: PMC9542607 DOI: 10.1002/nbm.4735] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/03/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
Magnetic resonance signals from different nuclei can be excited or received at the same time,rendering simultaneous or rapidly interleaved multi-nuclear acquisitions feasible. The advan-tages are a reduction of total scan time compared to sequential multi-nuclear acquisitions or that additional information from heteronuclear data is obtained at thesame time and anatomical position. Information content can be qualitatively increased by delivering a more comprehensive MR-based picture of a transient state (such as an exercise bout). Also, combiningnon-proton MR acquisitions with 1 Hinformation (e.g., dynamic shim updates and motion correction) can be used to improve data quality during long scans and benefits image coregistration. This work reviews the literature on interleaved and simultaneous multi-nuclear MRI and MRS in vivo. Prominent use cases for this methodology in clinical and research applications are brain and muscle, but studies have also been carried out in other targets, including the lung, knee, breast and heart. Simultaneous multi-nuclear measurements in the liver and kidney have also been performed, but exclusively in rodents. In this review, a consistent nomenclature is proposed, to help clarify the terminology used for this principle throughout the literature on in-vivo MR. An overview covers the basic principles, the technical requirements on the MR scanner and the implementations realised either by MR system vendors or research groups, from the early days until today. Considerations regarding the multi-tuned RF coils required and heteronuclear polarisation interactions are briefly discussed, and fields for future in-vivo applications for interleaved multi-nuclear MR pulse sequences are identified.
Collapse
Affiliation(s)
- Alfredo L. Lopez Kolkovsky
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of MyologyParisFrance
- NMR laboratoryCEA, DRF, IBFJParisFrance
| | - Pierre G. Carlier
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of MyologyParisFrance
- NMR laboratoryCEA, DRF, IBFJParisFrance
| | - Benjamin Marty
- NMR Laboratory, Neuromuscular Investigation CenterInstitute of MyologyParisFrance
- NMR laboratoryCEA, DRF, IBFJParisFrance
| | - Martin Meyerspeer
- High‐Field MR Center, Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| |
Collapse
|
4
|
Niess F, Roat S, Bogner W, Krššák M, Kemp GJ, Schmid AI, Trattnig S, Moser E, Zaitsev M, Meyerspeer M. 3D localized lactate detection in muscle tissue using double-quantum filtered 1 H MRS with adiabatic refocusing pulses at 7 T. Magn Reson Med 2021; 87:1174-1183. [PMID: 34719061 DOI: 10.1002/mrm.29061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
PURPOSE Lactate is a key metabolite in skeletal muscle and whole-body physiology. Its MR visibility in muscle is affected by overlapping lipid signals and fiber orientation. Double-quantum filtered (DQF) 1 H MRS selectively detects lactate at 1.3 ppm, but at ultra-high field the efficiency of slice-selective 3D-localization with conventional RF pulses is limited by bandwidth. This novel 3D-localized 1 H DQF MRS sequence uses adiabatic refocusing pulses to unambiguously detect lactate in skeletal muscle at 7 T. METHODS Lactate double-quantum coherences were 3D-localized using slice-selective Shinnar-Le Roux optimized excitation and adiabatic refocusing pulses (similar to semi-LASER). DQF MR spectra were acquired at 7 T from lactate phantoms, meat specimens with injected lactate (exploring multiple TEs and fiber orientations), and human gastrocnemius in vivo during and after exercise (without cuff ischemia). RESULTS Lactate was readily detected, achieving the full potential of 50% signal with a DQF, in solution. The effects of fiber orientation and TE on the lactate doublet (peak splitting, amplitude, and phase) were in good agreement with theory and literature. Exercise-induced lactate accumulation was detected with 30 s time resolution. CONCLUSION This novel 3D-localized 1 H DQF MRS sequence can dynamically detect glycolytically generated lactate in muscle during exercise and recovery at 7 T.
Collapse
Affiliation(s)
- Fabian Niess
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria.,High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Sigrun Roat
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Martin Krššák
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Graham J Kemp
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Albrecht I Schmid
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ewald Moser
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Maxim Zaitsev
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
5
|
Santos-Díaz A, Noseworthy MD. Phosphorus magnetic resonance spectroscopy and imaging (31P-MRS/MRSI) as a window to brain and muscle metabolism: A review of the methods. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.101967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
6
|
Niess F, Schmid AI, Bogner W, Wolzt M, Carlier P, Trattnig S, Moser E, Meyerspeer M. Interleaved 31 P MRS/ 1 H ASL for analysis of metabolic and functional heterogeneity along human lower leg muscles at 7T. Magn Reson Med 2019; 83:1909-1919. [PMID: 31846116 PMCID: PMC7065182 DOI: 10.1002/mrm.28088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/16/2019] [Accepted: 10/28/2019] [Indexed: 12/16/2022]
Abstract
PURPOSE MR offers the unique possibility to noninvasively investigate cellular energy metabolism via 31P MRS, while blood perfusion, which provides oxygen and substrates to the tissue, is accessible by arterial spin labeling (ASL) 1H MRI. Because metabolic and hemodynamic parameters are linked, it would be desirable to study them simultaneously. A 3D-resolved method is presented that allows such measurements with high spatiotemporal resolution and has the potential to discern differences along an exercising muscle. METHODS Multi-voxel localized 31 P MRS was temporally interleaved with multi-slice pASL 1H MRI. Phosphorus spectra were collected from two adjacent positions in gastrocnemius medialis (GM) during rest, submaximal plantar flexion exercise and recovery, while perfusion and T 2 * -weighted axial images were acquired at the same time. Seventeen healthy volunteers (9 f / 8 m) were studied at 7 T. RESULTS An increase of postexercise perfusion and T 2 * -weighted signal in GM positively correlated with end-exercise PCr depletion and pH drop. At proximal positions functional and metabolic activity was higher than distally, that is, perfusion increase and peak T 2 * -weighted signal, end-exercise PCr depletion, end-exercise pH, and PCr recovery time constant were significantly different. An NOE-induced SNR increase of approximately 20 % (P < .001), at rest, was found in interleaved 31 P spectra, when comparing to 31 P-only acquisitions. CONCLUSIONS A technique for fast, simultaneous imaging of muscle functional heterogeneity in ASL, T 2 * and acquisition of time-resolved 31 P MRS data is presented. These single exercise recovery experiments can be used to investigate local variations during disease progression in patients suffering from vascular or muscular diseases.
Collapse
Affiliation(s)
- Fabian Niess
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,High Field MR Center, Medical University of Vienna, Vienna, Austria
| | - Albrecht Ingo Schmid
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,High Field MR Center, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Center, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Siegfried Trattnig
- High Field MR Center, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,High Field MR Center, Medical University of Vienna, Vienna, Austria
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,High Field MR Center, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
7
|
Sedivy P, Dezortova M, Rydlo J, Drobny M, Krssak M, Valkovic L, Hajek M. MR compatible ergometers for dynamic 31P MRS. J Appl Biomed 2019; 17:91-98. [PMID: 34907736 DOI: 10.32725/jab.2019.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/15/2019] [Indexed: 11/05/2022] Open
Abstract
Magnetic Resonance (MR) compatible ergometers are specialized ergometers used inside the MR scanners for the characterization of tissue metabolism changes during physical stress. They are most commonly used for dynamic phosphorous magnetic resonance spectroscopy (31P MRS), but can also be used for lactate production measurements, perfusion studies using arterial spin labelling or muscle oxygenation measurements by blood oxygen dependent contrast sequences. We will primarily discuss the importance of ergometers in the context of dynamic 31P MRS. Dynamic 31P MRS can monitor muscle fatigue and energy reserve during muscle contractions as well as the dynamics of recuperation of skeletal muscle tissue during the following recovery through signal changes of phosphocreatine (PCr), inorganic phosphate and adenosine triphosphate (ATP). Based on the measured data it is possible to calculate intracellular pH, metabolic flux of ATP through creatine-kinase reaction, anaerobic glycolysis and oxidative phosphorylation and other metabolic parameters as mitochondrial capacity. This review primarily focuses on describing various technical designs of MR compatible ergometers for dynamic 31P MRS that must be constructed with respect to the presence of magnetic field. It is also expected that the construction of ergometers will be easy for the handling and well accepted by examined subjects.
Collapse
Affiliation(s)
- Petr Sedivy
- Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology, MR-unit, Prague, Czech Republic
| | - Monika Dezortova
- Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology, MR-unit, Prague, Czech Republic
| | - Jan Rydlo
- Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology, MR-unit, Prague, Czech Republic
| | - Miloslav Drobny
- Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology, MR-unit, Prague, Czech Republic
| | - Martin Krssak
- Medical University of Vienna, Department of Internal Medicine III & High Field MR Centre, Division of Endocrinology and Metabolism, Department of Biomedical Imaging and Image guided Therapy, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging (MOLIMA), Vienna, Austria
| | - Ladislav Valkovic
- University of Oxford, RDM Cardiovascular Medicine, Oxford Centre for Clinical MR Research (OCMR), Oxford, United Kingdom.,Slovak Academy of Sciences, Institute of Measurement Science, Department of Imaging Methods, Bratislava, Slovakia
| | - Milan Hajek
- Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology, MR-unit, Prague, Czech Republic
| |
Collapse
|
8
|
Santos-Díaz A, Harasym D, Noseworthy MD. Dynamic 31 P spectroscopic imaging of skeletal muscles combining flyback echo-planar spectroscopic imaging and compressed sensing. Magn Reson Med 2019; 81:3453-3461. [PMID: 30737840 DOI: 10.1002/mrm.27682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 01/21/2023]
Abstract
PURPOSE Dynamic phosphorus MR spectroscopic imaging (31 P-MRSI) experiments require temporal resolution on the order of seconds to concurrently assess different muscle groups. A highly accelerated pulse sequence combining flyback echo-planar spectroscopic imaging (EPSI) and compressed sensing was developed and tested in a phantom and healthy humans during an exercise-recovery challenge of the lower leg muscles, using a clinical 3T MRI. METHODS A flyback EPSI readout designed to achieve 2.25 × 2.25 cm2 resolution over a 18 × 18 cm2 field of view (i.e., 8 × 8 matrix) was combined with compressed sensing through the inclusion of pseudorandom gradient blips to sub-sample the ky-kt dimensions by a factor of 2.7×, achieving a temporal resolution of 9 s. The sequence was first tested in a phantom to assess performance compared to fully sampled EPSI (fidEPSI) and phase encoded chemical shift imaging (fidCSI). Then, tests were performed in 11 healthy volunteers during an exercise-recovery challenge of the lower leg muscles. Voxels containing tissue from different muscle groups were evaluated measuring percentage phosphocreatine (%PCr) depletion, time constant of PCr recovery (τPCr) and intracellular pH at rest and following exercise. RESULTS The sequence was capable to track the dynamic PCr response of multiple muscles simultaneously. No statistical differences were found in the metabolite ratio, pH or linewidth when compared with fidEPSI and fidCSI in the phantom study. Dynamic experiments showed differences in PCr depletion when comparing soleus with gastrocnemius muscles. Intracellular pH, τPCr and %PCr decrease were consistent with reported values. CONCLUSION Highly accelerated 31 P-MRSI combining flyback EPSI and compressed sensing is capable of assessing concurrent energy metabolism in multiple muscle groups using a clinical 3T MR system.
Collapse
Affiliation(s)
- Alejandro Santos-Díaz
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada.,Imaging Research Center, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Diana Harasym
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada.,Imaging Research Center, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Michael D Noseworthy
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada.,Imaging Research Center, St. Joseph's Healthcare, Hamilton, Ontario, Canada.,Electrical and Computing Engineering, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
9
|
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: 267] [Impact Index Per Article: 44.5] [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
|
10
|
Niess F, Fiedler GB, Schmid AI, Laistler E, Frass‐Kriegl R, Wolzt M, Moser E, Meyerspeer M. Dynamic multivoxel-localized 31 P MRS during plantar flexion exercise with variable knee angle. NMR IN BIOMEDICINE 2018; 31:e3905. [PMID: 29578260 PMCID: PMC6001778 DOI: 10.1002/nbm.3905] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 01/08/2018] [Accepted: 01/16/2018] [Indexed: 05/07/2023]
Abstract
Exercise studies investigating the metabolic response of calf muscles using 31 P MRS are usually performed with a single knee angle. However, during natural movement, the distribution of workload between the main contributors to force, gastrocnemius and soleus is influenced by the knee angle. Hence, it is of interest to measure the respective metabolic response of these muscles to exercise as a function of knee angle using localized spectroscopy. Time-resolved multivoxel 31 P MRS at 7 T was performed simultaneously in gastrocnemius medialis and soleus during rest, plantar flexion exercise and recovery in 12 healthy volunteers. This experiment was conducted with four different knee angles. PCr depletions correlated negatively with knee angle in gastrocnemius medialis, decreasing from 79±14 % (extended leg) to 35±23 %(∼40°), and positively in soleus, increasing from 20±21 % to 36±25 %; differences were significant. Linear correlations were found between knee angle and end-exercise PCr depletions in gastrocnemius medialis (R2 =0.8) and soleus (R2 =0.53). PCr recovery times and end-exercise pH changes that correlated with PCr depletion were consistent with the literature in gastrocnemius medialis and differences between knee angles were significant. These effects were less pronounced in soleus and not significant for comparable PCr depletions. Maximum oxidative capacity calculated for all knee angles was in excellent agreement with the literature and showed no significant changes between different knee angles. In conclusion, these findings confirm that plantar flexion exercise with a straight leg is a suitable paradigm, when data are acquired from gastrocnemius only (using either localized MRS or small surface coils), and that activation of soleus requires the knee to be flexed. The present study comprises a systematic investigation of the effects of the knee angle on metabolic parameters, measured with dynamic multivoxel 31 P MRS during muscle exercise and recovery, and the findings should be used in future study design.
Collapse
Affiliation(s)
- Fabian Niess
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| | - Georg B. Fiedler
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| | - Albrecht I. Schmid
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| | - Elmar Laistler
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| | - Roberta Frass‐Kriegl
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| | - Michael Wolzt
- Department of Clinical PharmacologyMedical University of ViennaAustria
| | - Ewald Moser
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaAustria
- Highfield MR CenterMedical University of ViennaAustria
| |
Collapse
|
11
|
Niess F, Fiedler GB, Schmid AI, Goluch S, Kriegl R, Wolzt M, Moser E, Meyerspeer M. Interleaved multivoxel 31 P MR spectroscopy. Magn Reson Med 2017; 77:921-927. [PMID: 26914656 PMCID: PMC4996323 DOI: 10.1002/mrm.26172] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/16/2016] [Accepted: 01/27/2016] [Indexed: 12/27/2022]
Abstract
PURPOSE Separate measurements are required when investigating multiple exercising muscles with singlevoxel-localized dynamic 31 P-MRS. With multivoxel spectroscopy, 31 P-MRS time-series spectra are acquired from multiple independent regions during one exercise-recovery experiment with the same time resolution as for singlevoxel measurements. METHODS Multiple independently selected volumes were localized using temporally interleaved semi-LASER excitations at 7T. Signal loss caused by mutual saturation from shared excitation or refocusing slices was quantified at partial and full overlap, and potential contamination was investigated in phantom measurements. During an exercise-recovery experiment both gastrocnemius medialis and soleus of two healthy volunteers were measured using multivoxel acquisitions with a total TR of 6 s, while avoiding overlap of excitation slices. RESULTS Signal reduction by shared adiabatic refocusing slices selected 1 s after the preceding voxel was between 10% (full overlap) and 20% (half overlap), in a phantom measurement. In vivo data were acquired from both muscles within the same exercise experiment, with 13-18% signal reduction. Spectra show phosphocreatine, inorganic phosphate, adenosine-triposphate, phosphomonoesters, and phosphodiesters. CONCLUSION Signal decrease was relatively low compared to the 2-fold increase in information. The approach could help to improve the understanding in metabolic research and is applicable to other organs and nuclei. Magn Reson Med 77:921-927, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Collapse
Affiliation(s)
- Fabian Niess
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
- Faculty of PhysicsTechnical University of ViennaViennaAustria
| | - Georg B. Fiedler
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Albrecht I. Schmid
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Sigrun Goluch
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Roberta Kriegl
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Michael Wolzt
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Ewald Moser
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical EngineeringMedical University of Vienna, ViennaAustria
- MR Center of Excellence, Medical University of ViennaViennaAustria
| |
Collapse
|
12
|
Valkovič L, Chmelík M, Krššák M. In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism. Anal Biochem 2017; 529:193-215. [PMID: 28119063 PMCID: PMC5478074 DOI: 10.1016/j.ab.2017.01.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 01/18/2023]
Abstract
In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy (31P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of 31P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry. This paper presents a methodological overview of the 31P-MR techniques that can be used for basic, physiological, or clinical research of human skeletal muscle and liver in vivo. Practical issues of 31P-MRS experiments and examples of potential applications are also provided. As signal localization is essential for liver 31P-MRS and is important for dynamic muscle examinations as well, typical localization strategies for 31P-MR are also described.
Collapse
Affiliation(s)
- Ladislav Valkovič
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Oxford, United Kingdom; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Marek Chmelík
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Institute for Clinical Molecular MRI in Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria
| | - Martin Krššák
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
13
|
A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 30:281-289. [PMID: 28054143 DOI: 10.1007/s10334-016-0605-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To develop a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems to reliably quantify metabolic parameters in human lower leg muscle using phosphorus magnetic resonance spectroscopy. MATERIALS AND METHODS We constructed an MR compatible ergometer using commercially available materials and elastic bands that provide resistance to movement. We recruited ten healthy subjects (eight men and two women, mean age ± standard deviation: 32.8 ± 6.0 years, BMI: 24.1 ± 3.9 kg/m2). All subjects were scanned on a 7 T whole-body magnet. Each subject was scanned on two visits and performed a 90 s plantar flexion exercise at 40% maximum voluntary contraction during each scan. During the first visit, each subject performed the exercise twice in order for us to estimate the intra-exam repeatability, and once during the second visit in order to estimate the inter-exam repeatability of the time constant of phosphocreatine recovery kinetics. We assessed the intra and inter-exam reliability in terms of the within-subject coefficient of variation (CV). RESULTS We acquired reliable measurements of PCr recovery kinetics with an intra- and inter-exam CV of 7.9% and 5.7%, respectively. CONCLUSION We constructed a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems, which allowed us to quantify reliably PCr recovery kinetics in lower leg muscle using 31P-MRS.
Collapse
|
14
|
Valkovič L, Chmelík M, Meyerspeer M, Gagoski B, Rodgers CT, Krššák M, Andronesi OC, Trattnig S, Bogner W. Dynamic 31 P-MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T. NMR IN BIOMEDICINE 2016; 29:1825-1834. [PMID: 27862510 PMCID: PMC5132121 DOI: 10.1002/nbm.3662] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/19/2016] [Accepted: 09/28/2016] [Indexed: 05/06/2023]
Abstract
Phosphorus MRSI (31 P-MRSI) using a spiral-trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle. The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunteers, who performed a plantar flexion exercise inside a whole-body 7 T MR scanner using an MR-compatible ergometer and a surface coil. In five volunteers the knee was flexed (~60°) to shift the major workload from the gastrocnemii to the soleus muscle. Spiral-encoded MRSI provided 16-25 times faster mapping with a better point spread function than elliptical phase-encoded MRSI with the same matrix size. The inevitable trade-off for the increased temporal resolution was a reduced signal-to-noise ratio, but this was acceptable. The phosphocreatine (PCr) depletion caused by exercise at 0° knee angulation was significantly higher in both gastrocnemii than in the soleus (i.e. 64.8 ± 19.6% and 65.9 ± 23.6% in gastrocnemius lateralis and medialis versus 15.3 ± 8.4% in the soleus). Spiral-encoded 31 P-MRSI is a powerful tool for dynamic mapping of exercising muscle oxidative metabolism, including localized assessment of PCr concentrations, pH and maximal oxidative flux with high temporal and spatial resolution.
Collapse
Affiliation(s)
- Ladislav Valkovič
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
- Department of Imaging Methods, Institute of Measurement ScienceSlovak Academy of SciencesBratislavaSlovakia
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUK
| | - Marek Chmelík
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Martin Meyerspeer
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Borjan Gagoski
- Fetal Neonatal Neuroimaging and Developmental Science CenterBoston Children's HospitalBostonMassachusettsUSA
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUK
| | - Martin Krššák
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Ovidiu C. Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Siegfried Trattnig
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Wolfgang Bogner
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| |
Collapse
|
15
|
Meyerspeer M, Magill AW, Kuehne A, Gruetter R, Moser E, Schmid AI. Simultaneous and interleaved acquisition of NMR signals from different nuclei with a clinical MRI scanner. Magn Reson Med 2016. [PMID: 26608834 DOI: 10.1002/mrm.26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
PURPOSE Modification of a clinical MRI scanner to enable simultaneous or rapid interleaved acquisition of signals from two different nuclei. METHODS A device was developed to modify the local oscillator signal fed to the receive channel(s) of an MRI console. This enables external modification of the frequency at which the receiver is sensitive and rapid switching between different frequencies. Use of the device was demonstrated with interleaved and simultaneous 31 P and 1 H spectroscopic acquisitions, and with interleaved 31 P and 1 H imaging. RESULTS Signal amplitudes and signal-to-noise ratios were found to be unchanged for the modified system, compared with data acquired with the MRI system in the standard configuration. CONCLUSION Interleaved and simultaneous 1 H and 31 P signal acquisition was successfully demonstrated with a clinical MRI scanner, with only minor modification of the RF architecture. While demonstrated with 31 P, the modification is applicable to any detectable nucleus without further modification, enabling a wide range of simultaneous and interleaved experiments to be performed within a clinical setting. Magn Reson Med 76:1636-1641, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Collapse
Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.
- MR Centre of Excellence, Medical University of Vienna, Austria.
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Arthur W Magill
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Department of Radiology, University of Lausanne, Lausanne, Switzerland
| | - Andre Kuehne
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
- MR Centre of Excellence, Medical University of Vienna, Austria
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Department of Radiology, University of Lausanne, Lausanne, Switzerland
- Department of Radiology, University of Geneva, Geneva, Switzerland
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
- MR Centre of Excellence, Medical University of Vienna, Austria
| | - Albrecht Ingo Schmid
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
- MR Centre of Excellence, Medical University of Vienna, Austria
| |
Collapse
|
16
|
Simple and effective exercise design for assessing in vivo mitochondrial function in clinical applications using (31)P magnetic resonance spectroscopy. Sci Rep 2016; 6:19057. [PMID: 26751849 PMCID: PMC4707472 DOI: 10.1038/srep19057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/02/2015] [Indexed: 02/02/2023] Open
Abstract
The growing recognition of diseases associated with dysfunction of mitochondria poses an urgent need for simple measures of mitochondrial function. Assessment of the kinetics of replenishment of the phosphocreatine pool after exercise using (31)P magnetic resonance spectroscopy can provide an in vivo measure of mitochondrial function; however, the wider application of this technique appears limited by complex or expensive MR-compatible exercise equipment and protocols not easily tolerated by frail participants or those with reduced mental capacity. Here we describe a novel in-scanner exercise method which is patient-focused, inexpensive, remarkably simple and highly portable. The device exploits an MR-compatible high-density material (BaSO4) to form a weight which is attached directly to the ankle, and a one-minute dynamic knee extension protocol produced highly reproducible measurements of post-exercise PCr recovery kinetics in both healthy subjects and patients. As sophisticated exercise equipment is unnecessary for this measurement, our extremely simple design provides an effective and easy-to-implement apparatus that is readily translatable across sites. Its design, being tailored to the needs of the patient, makes it particularly well suited to clinical applications, and we argue the potential of this method for investigating in vivo mitochondrial function in new cohorts of growing clinical interest.
Collapse
|
17
|
Šedivý P, Kipfelsberger MC, Dezortová M, Krššák M, Drobný M, Chmelík M, Rydlo J, Trattnig S, Hájek M, Valkovič L. Dynamic 31P MR spectroscopy of plantar flexion: influence of ergometer design, magnetic field strength (3 and 7 T), and RF-coil design. Med Phys 2015; 42:1678-89. [PMID: 25832057 DOI: 10.1118/1.4914448] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Dynamic phosphorus magnetic resonance spectroscopy ((31)P MRS) during and after acute exercise enables the noninvasive in vivo determination of the mitochondrial capacity of skeletal muscle. Nevertheless, the lack of standardization in experimental setups leads to significant variations in published values of maximal aerobic capacity, even in the population of healthy volunteers. Thus, in this study, we aimed to assess the impact of the ergometer type (pneumatic and mechanical resistance construction), radiofrequency (RF)-coil diameter, and different magnetic field strengths (3 and 7 T) on the metabolic parameters measured by dynamic (31)P MRS during a plantar flexion isotonic exercise protocol within the same group of healthy volunteers. METHODS Dynamic (31)P MRS measurements of the calf muscle in 11 volunteers (mean age, 36 ± 13 yrs; mean BMI, 23.5 ± 2.5 kg/m(2)), on a 3 T MR system with a custom-made mechanical ergometer in the first research laboratory (RL1) and on 3 and 7 T MR systems equipped with a commercial pneumatic ergometer in the second research laboratory (RL2), were performed at three different workloads. RF-coils differed slightly between the sites and MR systems used. The repeatability of the experimental protocol was tested in every setup. The basal concentrations of phosphocreatine (PCr), exercise-induced depletion of PCr (ΔPCr), initial PCr resynthesis rate (VPCr), and mitochondrial capacity (Qmax) were calculated and compared between the research sites and field strengths. RESULTS High repeatability of the measurement protocol was found in every experimental setup. No significant differences at any workload were found in these metabolic parameters assessed at different magnetic field strengths (3 T vs 7 T), using the same ergometer (in RL2) and a similar RF-coil. In the inter-research laboratory comparison at the same field strength (3 T), but with using different ergometers and RF-coils, differences were found in the concentration of PCr measured at rest and in the drop in PCr signal intensity. These differences translated into difference in the value of mitochondrial capacity at a workload of 15% of maximal voluntary contraction (MVC) force (0.45 ± 0.16 mM/s vs 0.31 ± 0.08 mM/s, in the RL1 and RL2, respectively). CONCLUSIONS Metabolic parameters measured during exercise challenge by dynamic (31)P MRS do not depend upon the magnetic field strength used. For multicenter studies with different ergometers, it is important to set the same workload, measurement, and evaluation protocols, especially when the effects of very mild exercise (15% MVC) are to be compared. However, a higher workload (24% MVC) decreases the influence of imperfections and intersite differences for the assessed value of maximal mitochondrial capacity.
Collapse
Affiliation(s)
- Petr Šedivý
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Monika Christina Kipfelsberger
- High-Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria and Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna A-1090, Austria
| | - Monika Dezortová
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Martin Krššák
- High-Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria; Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna A-1090, Austria; and Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna A-1090, Austria
| | - Miloslav Drobný
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Marek Chmelík
- High-Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria and Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna A-1090, Austria
| | - Jan Rydlo
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Siegfried Trattnig
- High-Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria and Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna A-1090, Austria
| | - Milan Hájek
- MR-Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Ladislav Valkovič
- High-Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava 841 04, Slovakia; and Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna A-1090, Austria
| |
Collapse
|
18
|
Meyerspeer M, Magill AW, Kuehne A, Gruetter R, Moser E, Schmid AI. Simultaneous and interleaved acquisition of NMR signals from different nuclei with a clinical MRI scanner. Magn Reson Med 2015; 76:1636-1641. [PMID: 26608834 PMCID: PMC4996325 DOI: 10.1002/mrm.26056] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 10/16/2015] [Accepted: 10/25/2015] [Indexed: 11/17/2022]
Abstract
Purpose Modification of a clinical MRI scanner to enable simultaneous or rapid interleaved acquisition of signals from two different nuclei. Methods A device was developed to modify the local oscillator signal fed to the receive channel(s) of an MRI console. This enables external modification of the frequency at which the receiver is sensitive and rapid switching between different frequencies. Use of the device was demonstrated with interleaved and simultaneous 31P and 1H spectroscopic acquisitions, and with interleaved 31P and 1H imaging. Results Signal amplitudes and signal‐to‐noise ratios were found to be unchanged for the modified system, compared with data acquired with the MRI system in the standard configuration. Conclusion Interleaved and simultaneous 1H and 31P signal acquisition was successfully demonstrated with a clinical MRI scanner, with only minor modification of the RF architecture. While demonstrated with 31P, the modification is applicable to any detectable nucleus without further modification, enabling a wide range of simultaneous and interleaved experiments to be performed within a clinical setting. Magn Reson Med 76:1636–1641, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Collapse
Affiliation(s)
- Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria. .,MR Centre of Excellence, Medical University of Vienna, Austria. .,Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Arthur W Magill
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Lausanne, Lausanne, Switzerland
| | - Andre Kuehne
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Geneva, Geneva, Switzerland
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Albrecht Ingo Schmid
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| |
Collapse
|
19
|
Schmid AI, Meyerspeer M, Robinson SD, Goluch S, Wolzt M, Fiedler GB, Bogner W, Laistler E, Krššák M, Moser E, Trattnig S, Valkovič L. Dynamic PCr and pH imaging of human calf muscles during exercise and recovery using (31) P gradient-Echo MRI at 7 Tesla. Magn Reson Med 2015; 75:2324-31. [PMID: 26115021 DOI: 10.1002/mrm.25822] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/15/2015] [Accepted: 06/01/2015] [Indexed: 12/26/2022]
Abstract
PURPOSE Simultaneous acquisition of spatially resolved (31) P-MRI data for evaluation of muscle specific energy metabolism, i.e., PCr and pH kinetics. METHODS A three-dimensional (3D) gradient-echo sequence for multiple frequency-selective excitations of the PCr and Pi signals in an interleaved sampling scheme was developed and tested at 7 Tesla (T). The pH values were derived from the chemical shift-induced phase difference between the resonances. The achieved spatial resolution was ∼2 mL with image acquisition time below 6 s. Ten healthy volunteers were studied performing plantar flexions during the delay between (31) P-MRI acquisitions, yielding a temporal resolution of 9-10 s. RESULTS Signal from anatomically matched regions of interest had sufficient signal-to-noise ratio to allow single-acquisition PCr and pH quantification. The Pi signal was clearly detected in voxels of actively exercising muscles. The PCr depletions were in gastrocnemius 42 ± 14% (medialis), 48 ± 17% (lateralis) and in soleus 20 ± 11%. The end exercise pH values were 6.74 ± 0.18 and 6.65 ± 0.27 for gastrocnemius medialis and lateralis, respectively, and 6.96 ± 0.12 for soleus muscle. CONCLUSION Simultaneous acquisition of PCr and Pi images with high temporal resolution, suitable for measuring PCr and pH kinetics in exercise-recovery experiments, was demonstrated at 7T. This study presents a fast alternative to MRS for quantifying energy metabolism of posterior muscle groups of the lower leg. Magn Reson Med 75:2324-2331, 2016. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Albrecht Ingo Schmid
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Meyerspeer
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Simon Daniel Robinson
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Sigrun Goluch
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Georg Bernd Fiedler
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Bogner
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Elmar Laistler
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Krššák
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.,Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Ewald Moser
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Siegfried Trattnig
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Ladislav Valkovič
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.,Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| |
Collapse
|
20
|
Fiedler GB, Meyerspeer M, Schmid AI, Goluch S, Schewzow K, Laistler E, Mirzahosseini A, Niess F, Unger E, Wolzt M, Moser E. Localized semi-LASER dynamic (31)P magnetic resonance spectroscopy of the soleus during and following exercise at 7 T. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2015; 28:493-501. [PMID: 25894813 DOI: 10.1007/s10334-015-0484-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 03/23/2015] [Accepted: 03/26/2015] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This study demonstrates the applicability of semi-LASER localized dynamic (31)P MRS to deeper lying areas of the exercising human soleus muscle (SOL). The effect of accurate localization and high temporal resolution on data specificity is investigated. MATERIALS AND METHODS To achieve high signal-to-noise ratio (SNR) at a temporal resolution of 6 s, a custom-built human calf coil array was used at 7T. The kinetics of phosphocreatine (PCr) and intracellular pH were quantified separately in SOL and gastrocnemius medialis (GM) muscle of nine volunteers, during rest, plantar flexion exercise, and recovery. RESULTS The average SNR of PCr at rest was [Formula: see text] in SOL ([Formula: see text] in GM). End exercise PCr depletion in SOL ([Formula: see text] %) was far lower than in GM ([Formula: see text] %). The pH in SOL increased rapidly and, in contrast to GM, remained elevated until the end of exercise. CONCLUSION (31)P MRS in single-shots every 6 s localized in the deeper-lying SOL enabled quantification of PCr recovery times at low depletions and of fast pH changes, like the initial rise. Both high temporal resolution and accurate spatial localization improve specificity of Pi and, thus, pH quantification by avoiding multiple, and potentially indistinguishable sources for changing the Pi peak shape.
Collapse
Affiliation(s)
- Georg B Fiedler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Albrecht I Schmid
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Sigrun Goluch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Kiril Schewzow
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Elmar Laistler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| | - Arash Mirzahosseini
- Department of Pharmaceutical Chemistry, Semmelweis University, Budapest, Hungary.,Research Group of Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences, Budapest, Hungary
| | - Fabian Niess
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria.,Graz University of Technology, Institute of Medical Engineering, Austria
| | - Ewald Unger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Austria
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Austria
| |
Collapse
|
21
|
Valkovič L, Chmelík M, Just Kukurová I, Jakubová M, Kipfelsberger MC, Krumpolec P, Tušek Jelenc M, Bogner W, Meyerspeer M, Ukropec J, Frollo I, Ukropcová B, Trattnig S, Krššák M. Depth-resolved surface coil MRS (DRESS)-localized dynamic (31) P-MRS of the exercising human gastrocnemius muscle at 7 T. NMR IN BIOMEDICINE 2014; 27:1346-1352. [PMID: 25199902 DOI: 10.1002/nbm.3196] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/04/2014] [Accepted: 07/31/2014] [Indexed: 06/03/2023]
Abstract
Dynamic (31) P-MRS with sufficiently high temporal resolution enables the non-invasive evaluation of oxidative muscle metabolism through the measurement of phosphocreatine (PCr) recovery after exercise. Recently, single-voxel localized (31) P-MRS was compared with surface coil localization in a dynamic fashion, and was shown to provide higher anatomical and physiological specificity. However, the relatively long TE needed for the single-voxel localization scheme with adiabatic pulses limits the quantification of J-coupled spin systems [e.g. adenosine triphosphate (ATP)]. Therefore, the aim of this study was to evaluate depth-resolved surface coil MRS (DRESS) as an alternative localization method capable of free induction decay (FID) acquisition for dynamic (31) P-MRS at 7 T. The localization performance of the DRESS sequence was tested in a phantom. Subsequently, two dynamic examinations of plantar flexions at 25% of maximum voluntary contraction were conducted in 10 volunteers, one examination with and one without spatial localization. The DRESS slab was positioned obliquely over the gastrocnemius medialis muscle, avoiding other calf muscles. Under the same load, significant differences in PCr signal drop (31.2 ± 16.0% versus 43.3 ± 23.4%), end exercise pH (7.06 ± 0.02 versus 6.96 ± 0.11), initial recovery rate (0.24 ± 0.13 mm/s versus 0.35 ± 0.18 mm/s) and maximum oxidative flux (0.41 ± 0.14 mm/s versus 0.54 ± 0.16 mm/s) were found between the non-localized and DRESS-localized data, respectively. Splitting of the inorganic phosphate (Pi) signal was observed in several non-localized datasets, but in none of the DRESS-localized datasets. Our results suggest that the application of the DRESS localization scheme yielded good spatial selection, and provided muscle-specific insight into oxidative metabolism, even at a relatively low exercise load. In addition, the non-echo-based FID acquisition allowed for reliable detection of ATP resonances, and therefore calculation of the specific maximum oxidative flux, in the gastrocnemius medialis using standard assumptions about resting ATP concentration in skeletal muscle.
Collapse
Affiliation(s)
- Ladislav Valkovič
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; High Field MR Center, Medical University of Vienna, Vienna, Austria; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Goluch S, Kuehne A, Meyerspeer M, Kriegl R, Schmid AI, Fiedler GB, Herrmann T, Mallow J, Hong SM, Cho ZH, Bernarding J, Moser E, Laistler E. A form-fitted three channel (31) P, two channel (1) H transceiver coil array for calf muscle studies at 7 T. Magn Reson Med 2014; 73:2376-89. [PMID: 25046817 DOI: 10.1002/mrm.25339] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 05/05/2014] [Accepted: 06/06/2014] [Indexed: 02/06/2023]
Abstract
PURPOSE To enhance sensitivity and coverage for calf muscle studies, a novel, form-fitted, three-channel phosphorus-31 ((31) P), two-channel proton ((1) H) transceiver coil array for 7 T MR imaging and spectroscopy is presented. METHODS Electromagnetic simulations employing individually generated voxel models were performed to design a coil array for studying nonpathological muscle metabolism. Static phase combinations of the coil elements' transmit fields were optimized based on homogeneity and efficiency for several voxel models. The best-performing design was built and tested both on phantoms and in vivo. RESULTS Simulations revealed that a shared conductor array for (31) P provides more robust interelement decoupling and better homogeneity than an overlap array in this configuration. A static B1 (+) shim setting that suited various calf anatomies was identified and implemented. Simulations showed that the (31) P array provides signal-to-noise ratio (SNR) benefits over a single loop and a birdcage coil of equal radius by factors of 3.2 and 2.6 in the gastrocnemius and by 2.5 and 2.0 in the soleus muscle. CONCLUSION The performance of the coil in terms of B1 (+) and achievable SNR allows for spatially localized dynamic (31) P spectroscopy studies in the human calf. The associated higher specificity with respect to nonlocalized measurements permits distinguishing the functional responses of different muscles.
Collapse
Affiliation(s)
- Sigrun Goluch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Andre Kuehne
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Roberta Kriegl
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,IR4M (Imagerie par Résonance Magnétique Médicale et Multi-Modalités), UMR808, Université Paris Sud-CNRS, Orsay, France
| | - Albrecht I Schmid
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Georg B Fiedler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Tim Herrmann
- Department of Biometrics and Medicine Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Johannes Mallow
- Department of Biometrics and Medicine Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Suk-Min Hong
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Zang-Hee Cho
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Johannes Bernarding
- Department of Biometrics and Medicine Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Elmar Laistler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
23
|
Schewzow K, Fiedler GB, Meyerspeer M, Goluch S, Laistler E, Wolzt M, Moser E, Schmid AI. Dynamic ASL and T2-weighted MRI in exercising calf muscle at 7 T: a feasibility study. Magn Reson Med 2014; 73:1190-5. [PMID: 24752959 DOI: 10.1002/mrm.25242] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 03/06/2014] [Accepted: 03/16/2014] [Indexed: 11/10/2022]
Abstract
PURPOSE The aim of this study was to develop a measurement protocol for noninvasive simultaneous perfusion quantification and T2 *-weighted MRI acquisition in the exercising calf muscle at 7 Tesla. METHODS Using a nonmagnetic ergometer and a dedicated in-house built calf coil array, dynamic pulsed arterial spin labeling (PASL) measurements with a temporal resolution of 12 s were performed before, during, and after plantar flexion exercise in 16 healthy volunteers. RESULTS Postexercise peak perfusion in gastrocnemius muscle (GAS) was 27 ± 16 ml/100g/min, whereas in soleus (SOL) and tibialis anterior (TA) muscles it remained at baseline levels. T2 *-weighted and ASL time courses in GAS showed comparable times to peak of 161 ± 72 s and 167 ± 115 s, respectively. The T2 *-weighted signal in the GAS showed a minimum during exercise (88 ± 6 % of the baseline signal) and a peak during the recovery (122 ± 9%), whereas in all other muscles only a signal decrease was observed (minimum 91 ± 6% in SOL; 87 ± 8% in TA). CONCLUSION We demonstrate the feasibility of dynamic perfusion quantification in skeletal muscle at 7 Tesla using PASL. This may help to better investigate the physiological processes in the skeletal muscle and also in diseases such as diabetes mellitus and peripheral arterial disease.
Collapse
Affiliation(s)
- Kiril Schewzow
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Tschiesche K, Rothamel M, Rzanny R, Gussew A, Hiepe P, Reichenbach JR. MR-compatible pedal ergometer for reproducible exercising of the human calf muscle. Med Eng Phys 2014; 36:933-7. [PMID: 24703504 DOI: 10.1016/j.medengphy.2014.02.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 02/14/2014] [Accepted: 02/27/2014] [Indexed: 11/29/2022]
Abstract
A pneumatic MR-compatible pedal ergometer was designed to perform dynamic contraction exercises of the human calf muscle in a whole-body 3T MR scanner. The set-up includes sensors for monitoring mechanical parameters, such as pedal angle, cadence as well as applied force and power. Actual parameter values during the exercise were presented to the volunteer as a visual feedback to enable real-time self-adjustment of pedal deflection and cadence to the target reference value. Time-resolved dynamic (31)P-MR spectroscopic measurements of phosphocreatine (PCr), inorganic phosphate (Pi) and pH were performed in a pilot experiment before, during, and after the exercise by a single volunteer. Two different load strengths were applied in these experiments (15% and 25% of the maximum voluntary contraction, MVC). As expected, mechanical and metabolic parameters differed for the two load levels. Small variations of the cadence, power and metabolic changes (time constants of PCr depletion and Pi accumulation) during the experiments demonstrate a highly reproducible mechanical output by the volunteer mediated by the ergometer.
Collapse
Affiliation(s)
- Kevin Tschiesche
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany.
| | - Markus Rothamel
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany; Medical Engineering and Biotechnology, Jena University of Applied Sciences (EAH Jena), Germany
| | - Reinhard Rzanny
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany
| | - Alexander Gussew
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany
| | - Patrick Hiepe
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany
| |
Collapse
|
25
|
Andreas M, Schmid AI, Doberer D, Schewzow K, Weisshaar S, Heinze G, Bilban M, Moser E, Wolzt M. Heme arginate improves reperfusion patterns after ischemia: a randomized, placebo-controlled trial in healthy male subjects. J Cardiovasc Magn Reson 2012; 14:55. [PMID: 22857721 PMCID: PMC3438022 DOI: 10.1186/1532-429x-14-55] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Accepted: 07/09/2012] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED BACKGROUND Heme arginate can induce heme oxygenase-1 to protect tissue against ischemia-reperfusion injury. Blood oxygen level dependent (BOLD) functional magnetic resonance imaging measures changes in tissue oxygenation with a high spatial and temporal resolution. BOLD imaging was applied to test the effect of heme arginate on experimental ischemia reperfusion injury in the calf muscles. METHODS A two period, controlled, observer blinded, crossover trial was performed in 12 healthy male subjects. Heme arginate (1 mg/kg body weight) or placebo were infused 24 h prior to a 20 min leg ischemia induced by a thigh cuff. 3 Tesla BOLD-imaging of the calf was performed and signal time courses from soleus, gastrocnemius and tibialis anterior muscle were available from 11 participants for technical reasons. RESULTS Peak reactive hyperemia signal of the musculature was significantly increased and occurred earlier after heme arginate compared to placebo (106.2 ± 0.6% at 175 ± 16s vs. 104.5 ± 0.6% at 221 ± 19s; p = 0.025 for peak reperfusion and p = 0.012 for time to peak). CONCLUSIONS A single high dose of heme arginate improves reperfusion patterns during ischemia reperfusion injury in humans. BOLD sensitive, functional MRI is applicable for the assessment of experimental ischemia reperfusion injury in skeletal muscle.
Collapse
Affiliation(s)
- Martin Andreas
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Albrecht Ingo Schmid
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
- MR Center of Excellence, Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria
| | - Daniel Doberer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Kiril Schewzow
- MR Center of Excellence, Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria
| | - Stefan Weisshaar
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Georg Heinze
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Martin Bilban
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Ewald Moser
- MR Center of Excellence, Center for Biomedical Engineering and Physics, Medical University of Vienna, Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
26
|
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
|
27
|
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
|
28
|
Schmid AI, Schrauwen-Hinderling VB, Andreas M, Wolzt M, Moser E, Roden M. Comparison of measuring energy metabolism by different (31) P-magnetic resonance spectroscopy techniques in resting, ischemic, and exercising muscle. Magn Reson Med 2011; 67:898-905. [PMID: 21842500 DOI: 10.1002/mrm.23095] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Alternate methods to quantify mitochondrial activity or function have been extensively used for studying insulin resistance and type 2 diabetes mellitus, namely saturation transfer and phosphocreatine (PCr) recovery. As these methods are in fact determining different parameters, this study aimed to compare saturation transfer results to PCr recovery measurements within the same group. Fifteen subjects underwent saturation transfer and ischemic exercise-recovery experiments. PCr decrease during ischemia (Q), induced by cuff inflation, served as an additional measure of resting ATP (adenosine triphosphate) production. ATP synthetic rate (fATP) measured by saturation transfer (0.234 ± 0.043 mM/s) was greater than (Q = 0.0077 ± 0.0011 mM/s), but correlated well with Q (r = 0.63 P = 0.013). Parameters of PCr recovery correlated well with fATP (Q(max,lin) : r = 0.71, P = 0.003, Q(max,ADP) : r = 0.66, P = 0.007) and Q (Q(max,lin) : r = 0.92, P = 0.000002, Q(max,ADP) : r = 0.76, P = 0.001). In conclusion, although saturation transfer yields higher ATP synthetic rates than PCr decrease during ischemia, their significant correlation indicates that fATP can be used as a marker of mitochondrial activity. The finding that both Q and fATP correlate with PCr recovery kinetics suggests that skeletal muscle with greater maximal aerobic ATP synthetic rates is also metabolically more active at rest. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.
Collapse
Affiliation(s)
- Albrecht I Schmid
- MR Center of Excellence, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | |
Collapse
|
29
|
Andreas M, Schmid AI, Keilani M, Doberer D, Bartko J, Crevenna R, Moser E, Wolzt M. Effect of ischemic preconditioning in skeletal muscle measured by functional magnetic resonance imaging and spectroscopy: a randomized crossover trial. J Cardiovasc Magn Reson 2011; 13:32. [PMID: 21718491 PMCID: PMC3143996 DOI: 10.1186/1532-429x-13-32] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/30/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Nuclear magnetic resonance (NMR) imaging and spectroscopy have been applied to assess skeletal muscle oxidative metabolism. Therefore, in-vivo NMR may enable the characterization of ischemia-reperfusion injury. The goal of this study was to evaluate whether NMR could detect the effects of ischemic preconditioning (IPC) in healthy subjects. METHODS Twenty-three participants were included in two randomized crossover protocols in which the effects of IPC were measured by NMR and muscle force assessments. Leg ischemia was administered for 20 minutes with or without a subsequent impaired reperfusion for 5 minutes (stenosis model). IPC was administered 4 or 48 hours prior to ischemia. Changes in 31phosphate NMR spectroscopy and blood oxygen level-dependent (BOLD) signals were recorded. 3-Tesla NMR data were compared to those obtained for isometric muscular strength. RESULTS The phosphocreatine (PCr) signal decreased robustly during ischemia and recovered rapidly during reperfusion. In contrast to PCr, the recovery of muscular strength was slow. During post-ischemic stenosis, PCr increased only slightly. The BOLD signal intensity decreased during ischemia, ischemic exercise and post-ischemic stenosis but increased during hyperemic reperfusion. IPC 4 hours prior to ischemia significantly increased the maximal PCr reperfusion signal and mitigated the peak BOLD signal during reperfusion. CONCLUSIONS Ischemic preconditioning positively influenced muscle metabolism during reperfusion; this resulted in an increase in PCr production and higher oxygen consumption, thereby mitigating the peak BOLD signal. In addition, an impairment of energy replenishment during the low-flow reperfusion was detected in this model. Thus, functional NMR is capable of characterizing changes in reperfusion and in therapeutic interventions in vivo. TRIAL REGISTRATION ClinicalTrials.gov: NCT00883467.
Collapse
Affiliation(s)
- Martin Andreas
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Albrecht I Schmid
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Mohammad Keilani
- Department of Physical Medicine and Rehabilitation, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Daniel Doberer
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Johann Bartko
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Richard Crevenna
- Department of Physical Medicine and Rehabilitation, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria
| |
Collapse
|
30
|
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: 36] [Impact Index Per Article: 2.8] [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
|
31
|
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
|
32
|
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
|
33
|
Abstract
Magnetic resonance spectroscopy (MRS) of skeletal muscle has been successfully applied by physiologists over several decades, particularly for studies of high-energy phosphates (by (31)P-MRS) and glycogen (by (13)C-MRS). Unfortunately, the observation of these heteronuclei requires equipment that is typically not available on clinical MR scanners, such as broadband capability and a second channel for decoupling and nuclear Overhauser enhancement (NOE). On the other hand, (1)H-MR spectra of skeletal muscle can be acquired on many routine MR systems and also provide a wealth of physiological information. In particular, studies of intramyocellular lipids (IMCL) attract physiologists and endocrinologists because IMCL levels are related to insulin resistance and thus can lead to a better understanding of major health problems in industrial countries. The combination of (1)H-, (13)C-, and (31)P-MRS gives access to the major long- and short-term energy sources of skeletal muscle. This review summarizes the technical aspects and unique MR-methodological features of the different nuclei. It reviews clinical studies that employed MRS of one or more nuclei, or combinations of MRS with other MR modalities. It also illustrates that MR spectra contain additional physiological information that is not yet used in routine clinical applications.
Collapse
Affiliation(s)
- Chris Boesch
- Department of Clinical Research, MR-Spectroscopy and Methodology, University of Bern, Bern, Switzerland.
| |
Collapse
|