1
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van den Wildenberg L, Gursan A, Seelen LWF, van der Velden TA, Gosselink MWJM, Froeling M, van der Kemp WJM, Klomp DWJ, Prompers JJ. In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole-body transmit coil and 16-channel receive array: Repeatability and effects of principal component analysis-based denoising. NMR IN BIOMEDICINE 2023; 36:e4877. [PMID: 36400716 DOI: 10.1002/nbm.4877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Quantitative three-dimensional (3D) imaging of phosphorus (31 P) metabolites is potentially a promising technique with which to assess the progression of liver disease and monitor therapy response. However, 31 P magnetic resonance spectroscopy has a low sensitivity and commonly used 31 P surface coils do not provide full coverage of the liver. This study aimed to overcome these limitations by using a 31 P whole-body transmit coil in combination with a 16-channel 31 P receive array at 7 T. Using this setup, we determined the repeatability of whole-liver 31 P magnetic resonance spectroscopic imaging (31 P MRSI) in healthy subjects and assessed the effects of principal component analysis (PCA)-based denoising on the repeatability parameters. In addition, spatial variations of 31 P metabolites within the liver were analyzed. 3D 31 P MRSI data of the liver were acquired with a nominal voxel size of 20 mm isotropic in 10 healthy volunteers twice on the same day. Data were reconstructed without denoising, and with PCA-based denoising before or after channel combination. From the test-retest data, repeatability parameters for metabolite level quantification were determined for 12 31 P metabolite signals. On average, 31 P MR spectra from 100 ± 25 voxels in the liver were analyzed. Only voxels with contamination from skeletal muscle or the gall bladder were excluded and no voxels were discarded based on (low) signal-to-noise ratio (SNR). Repeatability for most quantified 31 P metabolite levels in the liver was good to excellent, with an intrasubject variability below 10%. PCA-based denoising increased the SNR ~ 3-fold, but did not improve the repeatability for mean liver 31 P metabolite quantification with the fitting constraints used. Significant spatial heterogeneity of various 31 P metabolite levels within the liver was observed, with marked differences for the phosphomonoester and phosphodiester metabolites between the left and right lobe. In conclusion, using a 31 P whole-body transmit coil in combination with a 16-channel 31 P receive array at 7 T allowed 31 P MRSI acquisitions with full liver coverage and good to excellent repeatability.
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Affiliation(s)
| | - Ayhan Gursan
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leonard W F Seelen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tijl A van der Velden
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark W J M Gosselink
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martijn Froeling
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wybe J M van der Kemp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
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2
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Jett S, Dyke JP, Andy C, Schelbaum E, Jang G, Boneu Yepez C, Pahlajani S, Diaz I, Diaz Brinton R, Mosconi L. Sex and menopause impact 31P-Magnetic Resonance Spectroscopy brain mitochondrial function in association with 11C-PiB PET amyloid-beta load. Sci Rep 2022; 12:22087. [PMID: 36543814 PMCID: PMC9772209 DOI: 10.1038/s41598-022-26573-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Increasing evidence implicates sex and endocrine aging effects on brain bioenergetic aging in the greater lifetime risk of Alzheimer's disease (AD) in women. We conducted 31Phosphorus Magnetic Resonance Spectroscopy (31P-MRS) to assess the impact of sex and menopause on brain high-energy phosphates [adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi)] and membrane phospholipids [phosphomonoesters/phosphodiesters (PME/PDE)] in 216 midlife cognitively normal individuals at risk for AD, 80% female. Ninety-seven participants completed amyloid-beta (Aβ) 11C-PiB PET. Women exhibited higher ATP utilization than men in AD-vulnerable frontal, posterior cingulate, fusiform, medial and lateral temporal regions (p < 0.001). This profile was evident in frontal cortex at the pre-menopausal and peri-menopausal stage and extended to the other regions at the post-menopausal stage (p = 0.001). Results were significant after multi-variable adjustment for age, APOE-4 status, midlife health indicators, history of hysterectomy/oophorectomy, use of menopause hormonal therapy, and total intracranial volume. While associations between ATP/PCr and Aβ load were not significant, individuals with the highest Aβ load were post-menopausal and peri-menopausal women with ATP/PCr ratios in the higher end of the distribution. No differences in Pi/PCr, Pi/ATP or PME/PDE were detected. Outcomes are consistent with dynamic bioenergetic brain adaptations that are associated with female sex and endocrine aging.
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Affiliation(s)
- Steven Jett
- Department of Neurology, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Jonathan P Dyke
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Caroline Andy
- Department of Population Health Sciences, Weill Cornell Medicine, New York, NY, USA
| | - Eva Schelbaum
- Department of Neurology, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Grace Jang
- Department of Neurology, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Camila Boneu Yepez
- Department of Neurology, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Silky Pahlajani
- Department of Neurology, Weill Cornell Medicine, New York, NY, 10021, USA
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Ivan Diaz
- Department of Population Health Sciences, Weill Cornell Medicine, New York, NY, USA
| | - Roberta Diaz Brinton
- Department of Pharmacology, University of Arizona, Tucson, AZ, USA
- Department of Neurology, University of Arizona, Tucson, AZ, USA
| | - Lisa Mosconi
- Department of Neurology, Weill Cornell Medicine, New York, NY, 10021, USA.
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA.
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3
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Weis J, Jafar M, Liss P. Phosphorus MRS of healthy human spleen. NMR IN BIOMEDICINE 2022; 35:e4779. [PMID: 35642280 PMCID: PMC9540626 DOI: 10.1002/nbm.4779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Phosphorus (31 P-) MRS in vivo enables detection and quantification of important phosphorus-containing metabolites in biological tissues. 31 P-MRS of the normal spleen is challenging due to the relatively small volume and the larger distance between the spleen and surface coil. However, reference spectra of the healthy spleen are invaluable in studies of splenic malignancies and benign causes of splenomegaly, as well as in the study of its physiology. The purpose of this work was to investigate the feasibility of localized 31 P-MRS of healthy spleen in situ in a clinically acceptable measurement time using a clinical 3 T MR scanner. In this work, 31 P spectra of five healthy volunteers were measured using single-voxel image-selected in vivo spectroscopy (ISIS). The measurement sequence was augmented by broadband proton decoupling and nuclear Overhauser effect enhancement. It is demonstrated that localized 31 P-MRS of the spleen in situ using single-voxel ISIS is feasible on a clinical 3 T scanner in a clinically acceptable acquisition time. However, results have to be corrected for the transmitter excitation profile, and chemical shift displacement errors need to be taken into consideration during placement of the volume of interest. Results presented here could be used as a reference in future studies of splenomegaly caused by haematological malignancies.
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Affiliation(s)
- Jan Weis
- Department of Medical PhysicsUppsala University HospitalUppsalaSweden
| | | | - Per Liss
- Section of Radiology, Department of Surgical SciencesUniversity HospitalUppsalaSweden
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4
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Dziadosz M, Hoefemann M, Döring A, Marjańska M, Auerbach EJ, Kreis R. Quantification of
NAD
+
in human brain with
1
H MR
spectroscopy at 3 T: Comparison of three localization techniques with different handling of water magnetization. Magn Reson Med 2022; 88:1027-1038. [PMID: 35526238 PMCID: PMC9322547 DOI: 10.1002/mrm.29267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/11/2022] [Accepted: 03/25/2022] [Indexed: 12/16/2022]
Abstract
Purpose The detection of nicotinamide‐adenine‐dinucleotide (NAD+) is challenging using standard 1H MR spectroscopy, because it is of low concentration and affected by polarization‐exchange with water. Therefore, this study compares three techniques to access NAD+ quantification at 3 T–one with and two without water presaturation. Methods A large brain volume in 10 healthy subjects was investigated with three techniques: semi‐LASER with water‐saturation (WS) (TE = 35 ms), semi‐LASER with metabolite‐cycling (MC) (TE = 35 ms), and the non‐water‐excitation (nWE) technique 2D ISIS‐localization with chemical‐shift‐selective excitation (2D I‐CSE) (TE = 10.2 ms). Spectra were quantified with optimized modeling in FiTAID. Results NAD+ could be well quantified in cohort‐average spectra with all techniques. Obtained apparent NAD+ tissue contents are all lower than expected from literature confirming restricted visibility by 1H MRS. The estimated value from WS‐MRS (58 μM) was considerably lower than those obtained with non‐WS techniques (146 μM for MC‐semi‐LASER and 125 μM for 2D I‐CSE). The nWE technique with shortest TE gave largest NAD+ signals but suffered from overlap with large amide signals. MC‐semi‐LASER yielded best estimation precision as reflected in relative Cramer‐Rao bounds (14%, 21 μM/146 μM) and also best robustness as judged by the coefficient‐of‐variance over the cohort (11%, 10 μM/146 μM). The MR‐visibility turned out as 16% with WS and 41% with MC. Conclusion Three methods to assess NAD+ in human brain at 3 T have been compared. NAD+ could be detected with a visibility of ∼41% for the MC method. This may open a new window for the observation of pathological changes in the clinical research setting.
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Affiliation(s)
- Martyna Dziadosz
- MR Methodology, Department for Diagnostic and Interventional Neuroradiology & Department for Biomedical Research University of Bern Bern Switzerland
- Graduate School for Cellular and Biomedical Sciences University of Bern Bern Switzerland
- Translational Imaging Center (TIC) Swiss Institute for Translational and Entrepreneurial Medicine Bern Switzerland
| | - Maike Hoefemann
- MR Methodology, Department for Diagnostic and Interventional Neuroradiology & Department for Biomedical Research University of Bern Bern Switzerland
- Graduate School for Cellular and Biomedical Sciences University of Bern Bern Switzerland
- Translational Imaging Center (TIC) Swiss Institute for Translational and Entrepreneurial Medicine Bern Switzerland
| | - André Döring
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology Cardiff University Cardiff UK
| | - Malgorzata Marjańska
- Department of Radiology, Center for Magnetic Resonance Research University of Minnesota Minneapolis Minnesota USA
| | - Edward John Auerbach
- Department of Radiology, Center for Magnetic Resonance Research University of Minnesota Minneapolis Minnesota USA
| | - Roland Kreis
- MR Methodology, Department for Diagnostic and Interventional Neuroradiology & Department for Biomedical Research University of Bern Bern Switzerland
- Translational Imaging Center (TIC) Swiss Institute for Translational and Entrepreneurial Medicine Bern Switzerland
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5
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Shaffer A, Kwok SS, Naik A, Anderson AT, Lam F, Wszalek T, Arnold PM, Hassaneen W. Ultra-High-Field MRI in the Diagnosis and Management of Gliomas: A Systematic Review. Front Neurol 2022; 13:857825. [PMID: 35449515 PMCID: PMC9016277 DOI: 10.3389/fneur.2022.857825] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/02/2022] [Indexed: 12/03/2022] Open
Abstract
Importance: Gliomas, tumors of the central nervous system, are classically diagnosed through invasive surgical biopsy and subsequent histopathological study. Innovations in ultra-high field (UHF) imaging, namely 7-Tesla magnetic resonance imaging (7T MRI) are advancing preoperative tumor grading, visualization of intratumoral structures, and appreciation of small brain structures and lesions. Objective Summarize current innovative uses of UHF imaging techniques in glioma diagnostics and treatment. Methods A systematic review in accordance with PRISMA guidelines was performed utilizing PubMed. Case reports and series, observational clinical trials, and randomized clinical trials written in English were included. After removing unrelated studies and those with non-human subjects, only those related to 7T MRI were independently reviewed and summarized for data extraction. Some preclinical animal models are briefly described to demonstrate future usages of ultra-high-field imaging. Results We reviewed 46 studies (43 human and 3 animal models) which reported clinical usages of UHF MRI in the diagnosis and management of gliomas. Current literature generally supports greater resolution imaging from 7T compared to 1.5T or 3T MRI, improving visualization of cerebral microbleeds and white and gray matter, and providing more precise localization for radiotherapy targeting. Additionally, studies found that diffusion or susceptibility-weighted imaging techniques applied to 7T MRI, may be used to predict tumor grade, reveal intratumoral structures such as neovasculature and microstructures like axons, and indicate isocitrate dehydrogenase 1 mutation status in preoperative imaging. Similarly, newer imaging techniques such as magnetic resonance spectroscopy and chemical exchange saturation transfer imaging can be performed on 7T MRI to predict tumor grading and treatment efficacy. Geometrical distortion, a known challenge of 7T MRI, was at a tolerable level in all included studies. Conclusion UHF imaging has the potential to preoperatively and non-invasively grade gliomas, provide precise therapy target areas, and visualize lesions not seen on conventional MRI.
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Affiliation(s)
- Annabelle Shaffer
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Susanna S Kwok
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Anant Naik
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Aaron T Anderson
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL, United States.,Carle Illinois Advanced Imaging Center, University of Illinois and Carle Health, Urbana, IL, United States
| | - Fan Lam
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL, United States.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL, United States.,Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Tracey Wszalek
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL, United States.,Carle Illinois Advanced Imaging Center, University of Illinois and Carle Health, Urbana, IL, United States
| | - Paul M Arnold
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States.,Carle Department of Neurosurgery, Carle Foundation Hospital, Urbana, IL, United States
| | - Wael Hassaneen
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States.,Carle Department of Neurosurgery, Carle Foundation Hospital, Urbana, IL, United States
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6
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Jacqmot O, Van Thielen B, Hespel AM, Luijten PR, de Mey J, Van Binst A, Provyn S, Tresignie J. T2-weighted turbo spin-echo magnetic resonance imaging of canine brain anatomy at 1.5T, 3T, and 7T field strengths. Anat Rec (Hoboken) 2021; 305:222-233. [PMID: 34357697 DOI: 10.1002/ar.24724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 06/10/2021] [Accepted: 06/20/2021] [Indexed: 01/07/2023]
Abstract
Post-mortem T2 weighted images of canine heads were acquired at 1.5T, 3T, and 7T. This study aimed to (1) identify anatomical structures of the canine brain using an ultra-high-field magnetic resonance imaging (MRI) (7T) to help to facilitate their localization on high field MRI images (3T and 1.5T), where these structures may appear less well defined and delineated and (2) evaluate the visibility of canine brain anatomical structures on 1.5T, 3T, and 7T MRI images for optimizing clinical utility. Our hypothesis was that the provided subjective image quality comparison at different field strengths may offer a general baseline for canine brain anatomy and may help clinicians evaluate MRI options better. Six canine heads were examined with 1.5T, 3T, and 7T MRI scanners. T2-weighted images were acquired in three orthogonal planes at each field strength using a turbo spin-echo sequence. Fifty neuroanatomic structures were identified and evaluated on the 7T MR images; subsequently, those were found on the 3T and 45 out of the 50 structures were detected on the 1.5T imaging. The structures that were not able to be identified on the 1.5T imaging included the septum pellucidum, oculomotor nucleus, substantia nigra, claustrum, and thalamic nucleus griseus. Images acquired at 7T were subjective of higher spatial and contrast resolution. However, the ultra-high-field images were prone to artifacts at the interface between tissues of different magnetic properties. In conclusion, 3T MR imaging appears to be the best comprise for evaluating canine brain anatomy on MRI with fewer imaging artifacts.
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Affiliation(s)
- Olivier Jacqmot
- Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel, Brussels, Belgium.,MOVE - HIM (Morpho Veterinary & Human Imaging) Brussels, University Hospital Brussels, UZ Brussel, Brussel, Belgium
| | - Bert Van Thielen
- MOVE - HIM (Morpho Veterinary & Human Imaging) Brussels, University Hospital Brussels, UZ Brussel, Brussel, Belgium.,Department of Radiology, University Hospital Brussels, UZ Brussel, Brussels, Belgium.,Anatomical Research, Training and Education (ARTE), Vrije Universiteit Brussel, VUB, Brussels, Belgium
| | | | - Peter R Luijten
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Johan de Mey
- Department of Radiology, University Hospital Brussels, UZ Brussel, Brussels, Belgium
| | - Anne Van Binst
- Department of Radiology, University Hospital Brussels, UZ Brussel, Brussels, Belgium
| | - Steven Provyn
- Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel, Brussels, Belgium.,Anatomical Research, Training and Education (ARTE), Vrije Universiteit Brussel, VUB, Brussels, Belgium
| | - Jonathan Tresignie
- Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel, Brussels, Belgium
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7
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Ruhm L, Dorst J, Avdievitch N, Wright AM, Henning A. 3D 31 P MRSI of the human brain at 9.4 Tesla: Optimization and quantitative analysis of metabolic images. Magn Reson Med 2021; 86:2368-2383. [PMID: 34219281 DOI: 10.1002/mrm.28891] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 05/14/2021] [Accepted: 05/28/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE To present 31 P whole brain MRSI with a high spatial resolution to probe quantitative tissue analysis of 31 P MRSI at an ultrahigh field strength of 9.4 Tesla. METHODS The study protocol included a 31 P MRSI measurement with an effective resolution of 2.47 mL. For SNR optimization, the nuclear Overhauser enhancement at 9.4 Tesla was investigated. A sensitivity correction was achieved by applying a low rank approximation of the γ-adenosine triphosphate signal. Group analysis and regression on individual volunteers were performed to investigate quantitative concentration differences between different tissue types. RESULTS Differences in gray and white matter tissue 31 P concentrations could be investigated for 12 different 31 P resonances. In addition, the first highly resolved quantitative MRSI images measured at B0 = 9.4 Tesla of 31 P detectable metabolites with high SNR could be presented. CONCLUSION With an ultrahigh field strength B0 = 9.4 Tesla, 31 P MRSI moves further toward quantitative metabolic imaging, and subtle differences in concentrations between different tissue types can be detected.
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Affiliation(s)
- Loreen Ruhm
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tübingen, Germany
| | - Johanna Dorst
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tübingen, Germany
| | - Nikolai Avdievitch
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Andrew Martin Wright
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tübingen, Germany
| | - Anke Henning
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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8
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Rothe M, Wessel C, Cames S, Szendroedi J, Burkart V, Hwang JH, Roden M. In vivo absolute quantification of hepatic γ-ATP concentration in mice using 31 P MRS at 11.7 T. NMR IN BIOMEDICINE 2021; 34:e4422. [PMID: 33025629 DOI: 10.1002/nbm.4422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
Measurement of ATP concentrations and synthesis in humans indicated abnormal hepatic energy metabolism in obesity, non-alcoholic fatty liver disease (NAFLD) and Type 2 diabetes. Further mechanistic studies on energy metabolism require the detailed phenotyping of specific mouse models. Thus, this study aimed to establish and evaluate a robust and fast single voxel 31 P MRS method to quantify hepatic γ-ATP concentrations at 11.7 T in three mouse models with different insulin sensitivities and liver fat contents (72-week-old C57BL/6 control mice, 72-week-old insulin resistant sterol regulatory-element binding protein-1c overexpressing (SREBP-1c+ ) mice and 10-12-week-old prediabetic non-obese diabetic (NOD) mice). Absolute quantification was performed by employing an external reference and a matching replacement ATP phantom with 3D image selected in vivo spectroscopy 31 P MRS. This single voxel 31 P MRS method non-invasively quantified hepatic γ-ATP within 17 min and the repeatability tests provided a coefficient of variation of 7.8 ± 1.1%. The mean hepatic γ-ATP concentrations were markedly lower in SREBP-1c+ mice (1.14 ± 0.10 mM) than in C57BL/6 mice (2.15 ± 0.13 mM; p < 0.0002) and NOD mice (1.78 ± 0.13 mM; p < 0.006, one-way ANOVA test). In conclusion, this method allows us to rapidly and precisely measure hepatic γ-ATP concentrations, and thereby to non-invasively detect abnormal hepatic energy metabolism in mice with different degrees of insulin resistance and NAFLD. Thus, this 31 P MRS will also be useful for future mechanistic as well as therapeutic translational studies in other murine models.
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Affiliation(s)
- Maik Rothe
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Corinna Wessel
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Sandra Cames
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Julia Szendroedi
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Volker Burkart
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Jong-Hee Hwang
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University, Leibniz Institute for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
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9
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Dorst J, Ruhm L, Avdievich N, Bogner W, Henning A. Comparison of four 31P single-voxel MRS sequences in the human brain at 9.4 T. Magn Reson Med 2021; 85:3010-3026. [PMID: 33427322 DOI: 10.1002/mrm.28658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 01/30/2023]
Abstract
PURPOSE In this study, different single-voxel localization sequences were implemented and systematically compared for the first time for phosphorous MRS (31 P-MRS) in the human brain at 9.4 T. METHODS Two multishot sequences, image-selected in vivo spectroscopy (ISIS) and a conventional slice-selective excitation combined with localization by adiabatic selective refocusing (semiLASER) variant of the spin-echo full intensity-acquired localized spectroscopy (SPECIAL-semiLASER), and two single-shot sequences, semiLASER and stimulated echo acquisition mode (STEAM), were implemented and optimized for 31 P-MRS in the human brain at 9.4 T. Pulses and coil setup were optimized, localization accuracy was tested in phantom experiments, and absolute SNR of the sequences was compared in vivo. The SNR per unit time (SNR/t) was derived and compared for all four sequences and verified experimentally for ISIS in two different voxel sizes (3 × 3 × 3 cm3 , 5 × 5 × 5 cm3 , 10-minute measurement time). Metabolite signals obtained with ISIS were quantified. The possible spectral quality in vivo acquired in clinically feasible time (3:30 minutes, 3 × 3 × 3 cm3 ) was explored for two different coil setups. RESULTS All evaluated sequences performed with good localization accuracy in phantom experiments and provided well-resolved spectra in vivo. However, ISIS has the lowest chemical shift displacement error, the best localization accuracy, the highest SNR/t for most metabolites, provides metabolite concentrations comparable to literature values, and is the only one of the sequences that allows for the detection of the whole 31 P spectrum, including β-adenosine triphosphate, with the used setup. The SNR/t of STEAM is comparable to the SNR/t of ISIS. The semiLASER and SPECIAL-semiLASER sequences provide good results for metabolites with long T2 . CONCLUSION At 9.4 T, high-quality single-voxel localized 31 P-MRS can be performed in the human brain with different localization methods, each with inherent characteristics suitable for different research issues.
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Affiliation(s)
- Johanna Dorst
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany
| | - Loreen Ruhm
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany
| | - Nikolai Avdievich
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Wolfgang Bogner
- High-Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Anke Henning
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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10
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Santos-Díaz A, Noseworthy MD. Phosphorus magnetic resonance spectroscopy and imaging (31P-MRS/MRSI) as a window to brain and muscle metabolism: A review of the methods. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.101967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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11
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Dziadosz M, Bogner W, Kreis R. Non-water-excitation MR spectroscopy techniques to explore exchanging protons in human brain at 3 T. Magn Reson Med 2020; 84:2352-2363. [PMID: 32602971 DOI: 10.1002/mrm.28322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE To develop localization sequences for in vivo MR spectroscopy (MRS) on clinical scanners of 3 T to record spectra that are not influenced by magnetization transfer from water. METHODS Image-selected in vivo spectroscopy (ISIS) localization and chemical-shift-selective excitation (termed I-CSE) was combined in two ways: first, full ISIS localization plus a frequency-selective spin-echo and second, two-dimensional (2D) ISIS plus a frequency-selective excitation and slice-selective refocusing. The techniques were evaluated at 3 T in phantoms and human subjects in comparison to standard techniques with water presaturation or metabolite-cycling. ISIS included gradient-modulated offset-independent adiabatic (GOIA)-type adiabatic inversion pulses; echo times were 8-10 ms. RESULTS The novel 2D and 3D I-CSE methods yield upfield spectra that are comparable to those from standard MRS, except for shorter echo times and a limited frequency range. On the downfield/high-frequency side, they yield much more signal for exchangeable protons when compared to MRS with water presaturation or metabolite-cycling and longer echo times. CONCLUSION Novel non-water-excitation MRS sequences offer substantial benefits for the detection of metabolite signals that are otherwise suppressed by saturation transfer from water. Avoiding water saturation and using very short echo times allows direct observation of faster exchanging moieties than was previously possible at 3 T and additionally makes the methods less susceptible to fast T2 relaxation.
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Affiliation(s)
- Martyna Dziadosz
- Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Wolfgang Bogner
- High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Roland Kreis
- Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland
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12
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Avdievich NI, Ruhm L, Dorst J, Scheffler K, Korzowski A, Henning A. Double‐tuned
31
P/
1
H human head array with high performance at both frequencies for spectroscopic imaging at 9.4T. Magn Reson Med 2020; 84:1076-1089. [DOI: 10.1002/mrm.28176] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/30/2019] [Accepted: 12/30/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Nikolai I. Avdievich
- High‐Field MR Center Max Planck Institute for Biological Cybernetics Tübingen Germany
| | - Loreen Ruhm
- High‐Field MR Center Max Planck Institute for Biological Cybernetics Tübingen Germany
| | - Johanna Dorst
- High‐Field MR Center Max Planck Institute for Biological Cybernetics Tübingen Germany
| | - Klaus Scheffler
- High‐Field MR Center Max Planck Institute for Biological Cybernetics Tübingen Germany
- Department for Biomedical Magnetic Resonance University of Tübingen Tübingen Germany
| | - Andreas Korzowski
- Department for Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Anke Henning
- High‐Field MR Center Max Planck Institute for Biological Cybernetics Tübingen Germany
- Advanced Imaging Research Center University of Texas Southwestern Medical Center Dallas Texas
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13
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Pfleger L, Gajdošík M, Wolf P, Smajis S, Fellinger P, Kuehne A, Krumpolec P, Trattnig S, Winhofer Y, Krebs M, Krššák M, Chmelík M. Absolute Quantification of Phosphor-Containing Metabolites in the Liver Using 31 P MRSI and Hepatic Lipid Volume Correction at 7T Suggests No Dependence on Body Mass Index or Age. J Magn Reson Imaging 2018; 49:597-607. [PMID: 30291654 PMCID: PMC6586048 DOI: 10.1002/jmri.26225] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 01/07/2023] Open
Abstract
Background Hepatic disorders are often associated with changes in the concentration of phosphorus‐31 (31P) metabolites. Absolute quantification offers a way to assess those metabolites directly but introduces obstacles, especially at higher field strengths (B0 ≥ 7T). Purpose To introduce a feasible method for in vivo absolute quantification of hepatic 31P metabolites and assess its clinical value by probing differences related to volunteers' age and body mass index (BMI). Study Type Prospective cohort. Subjects/Phantoms Four healthy volunteers included in the reproducibility study and 19 healthy subjects arranged into three subgroups according to BMI and age. Phantoms containing 31P solution for correction and validation. Field Strength/Sequence Phase‐encoded 3D pulse‐acquire chemical shift imaging for 31P and single‐volume 1H spectroscopy to assess the hepatocellular lipid content at 7T. Assessment A phantom replacement method was used. Spectra located in the liver with sufficient signal‐to‐noise ratio and no contamination from muscle tissue, were used to calculate following metabolite concentrations: adenosine triphosphates (γ‐ and α‐ATP); glycerophosphocholine (GPC); glycerophosphoethanolamine (GPE); inorganic phosphate (Pi); phosphocholine (PC); phosphoethanolamine (PE); uridine diphosphate‐glucose (UDPG); nicotinamide adenine dinucleotide‐phosphate (NADH); and phosphatidylcholine (PtdC). Correction for hepatic lipid volume fraction (HLVF) was performed. Statistical Tests Differences assessed by analysis of variance with Bonferroni correction for multiple comparison and with a Student's t‐test when appropriate. Results The concentrations for the young lean group corrected for HLVF were 2.56 ± 0.10 mM for γ‐ATP (mean ± standard deviation), α‐ATP: 2.42 ± 0.15 mM, GPC: 3.31 ± 0.27 mM, GPE: 3.38 ± 0.87 mM, Pi: 1.42 ± 0.20 mM, PC: 1.47 ± 0.24 mM, PE: 1.61 ± 0.20 mM, UDPG: 0.74 ± 0.17 mM, NADH: 1.21 ± 0.38 mM, and PtdC: 0.43 ± 0.10 mM. Differences found in ATP levels between lean and overweight volunteers vanished after HLVF correction. Data Conclusion Exploiting the excellent spectral resolution at 7T and using the phantom replacement method, we were able to quantify up to 10 31P‐containing hepatic metabolites. The combination of 31P magnetic resonance spectroscopy imaging data acquisition and HLVF correction was not able to show a possible dependence of 31P metabolite concentrations on BMI or age, in the small healthy population used in this study. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:597–607.
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Affiliation(s)
- Lorenz Pfleger
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Martin Gajdošík
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
| | - Peter Wolf
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Sabina Smajis
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Paul Fellinger
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Andre Kuehne
- MRI.TOOLS GmbHBerlinGermany
- Medical University of Vienna, Center for Medical Physics and Biomedical EngineeringViennaAustria
| | - Patrik Krumpolec
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
- Slovak Academy of Sciences, Biomedical Research Center, Institute of Experimental EndocrinologyBratislavaSlovakia
| | - Siegfried Trattnig
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
- Medical University of Vienna, Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMAViennaAustria
| | - Yvonne Winhofer
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Michael Krebs
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
| | - Martin Krššák
- Medical University of Vienna, Department of Internal Medicine III, Division of Endocrinology and MetabolismViennaAustria
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
- Medical University of Vienna, Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMAViennaAustria
| | - Marek Chmelík
- Medical University of Vienna, Department of Biomedical Imaging and Image‐guided Therapy, High Field MR CenterViennaAustria
- Medical University of Vienna, Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMAViennaAustria
- Karl Landsteiner Institute for Clinical Molecular MRViennaAustria
- University of PrešovFaculty of HealthcarePrešovSlovakia
- General Hospital of Levoča, Radiology DepartmentLevočaSlovakia
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14
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van der Kemp WJ, Klomp DW, Wijnen JP. 31 P T 2 s of phosphomonoesters, phosphodiesters, and inorganic phosphate in the human brain at 7T. Magn Reson Med 2018; 80:29-35. [PMID: 29215148 PMCID: PMC5900879 DOI: 10.1002/mrm.27026] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/03/2017] [Accepted: 11/03/2017] [Indexed: 01/21/2023]
Abstract
PURPOSE To determine the phosphorus-31 T2 s of phosphomonoesters, phosphodiesters, and inorganic phosphate in the healthy human brain at 7T. METHODS A 3D chemical shift imaging multi-echo sequence with composite block pulses for refocusing was used to measure one free induction decay (FID) and seven full echoes with an echo spacing of 45 ms on the brain of nine healthy volunteers (age range 22-45 years; average age 27 ± 8 years). Spectral fitting was used to determine the change in metabolic signal amplitude with echo time. RESULTS The average apparent T2 s with their standard deviation were 202 ± 6 ms, 129 ± 6 ms, 86 ± 2 ms, 214 ± 10 ms, and 213 ± 11 ms for phosphoethanolamine, phosphocholine, inorganic phosphate, glycerophosphoethanolamine, and glycerophosphocholine, respectively. CONCLUSION The determined apparent T2 for phosphoethanolamine, glycerophosphocholine, and glycerophosphoethanolamine is approximately 200 ms. The lower apparent T2 value for phosphocholine is attributed to the overlap of this resonance with the 3-phosphorous resonance of 2,3-diphosphoglycerate from blood, with an apparent shorter T2 . Omitting the FID signal and the first echo of phosphocholine leads to a T2 of 182 ± 7 ms, whereas a biexponential analysis leads to 203 ± 4 ms. These values are more in line with phosphoethanolamine and the phosphodiesters. The short T2 of inorganic phosphate is subscribed to the fast reversible exchange with γ-adenosine triphosphate, which is mediated by glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase within the glycolytic pathway. Magn Reson Med 80:29-35, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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Affiliation(s)
| | - Dennis W.J. Klomp
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Jannie P. Wijnen
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
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Trattnig S, Springer E, Bogner W, Hangel G, Strasser B, Dymerska B, Cardoso PL, Robinson SD. Key clinical benefits of neuroimaging at 7T. Neuroimage 2018; 168:477-489. [PMID: 27851995 PMCID: PMC5832016 DOI: 10.1016/j.neuroimage.2016.11.031] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/06/2016] [Accepted: 11/12/2016] [Indexed: 01/15/2023] Open
Abstract
The growing interest in ultra-high field MRI, with more than 35.000 MR examinations already performed at 7T, is related to improved clinical results with regard to morphological as well as functional and metabolic capabilities. Since the signal-to-noise ratio increases with the field strength of the MR scanner, the most evident application at 7T is to gain higher spatial resolution in the brain compared to 3T. Of specific clinical interest for neuro applications is the cerebral cortex at 7T, for the detection of changes in cortical structure, like the visualization of cortical microinfarcts and cortical plaques in Multiple Sclerosis. In imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology may be visualized with excellent spatial resolution. Using Susceptibility Weighted Imaging, the plaque-vessel relationship and iron accumulations in Multiple Sclerosis can be visualized, which may provide a prognostic factor of disease. Vascular imaging is a highly promising field for 7T which is dealt with in a separate dedicated article in this special issue. The static and dynamic blood oxygenation level-dependent contrast also increases with the field strength, which significantly improves the accuracy of pre-surgical evaluation of vital brain areas before tumor removal. Improvement in acquisition and hardware technology have also resulted in an increasing number of MR spectroscopic imaging studies in patients at 7T. More recent parallel imaging and short-TR acquisition approaches have overcome the limitations of scan time and spatial resolution, thereby allowing imaging matrix sizes of up to 128×128. The benefits of these acquisition approaches for investigation of brain tumors and Multiple Sclerosis have been shown recently. Together, these possibilities demonstrate the feasibility and advantages of conducting routine diagnostic imaging and clinical research at 7T.
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Affiliation(s)
- Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MRI, Vienna, Austria.
| | - Elisabeth Springer
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MRI, Vienna, Austria.
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Gilbert Hangel
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Bernhard Strasser
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Barbara Dymerska
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Pedro Lima Cardoso
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
| | - Simon Daniel Robinson
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
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Springer E, Dymerska B, Cardoso PL, Robinson SD, Weisstanner C, Wiest R, Schmitt B, Trattnig S. Comparison of Routine Brain Imaging at 3 T and 7 T. Invest Radiol 2017; 51:469-82. [PMID: 26863580 DOI: 10.1097/rli.0000000000000256] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this study was to compare quantitative and semiquantitative parameters (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], image quality, diagnostic confidence) from a standard brain magnetic resonance imaging examination encompassing common neurological disorders such as demyelinating disease, gliomas, cerebrovascular disease, and epilepsy, with comparable sequence protocols and acquisition times at 3 T and at 7 T. MATERIALS AND METHODS Ten healthy volunteers and 4 subgroups of 40 patients in total underwent comparable magnetic resonance protocols with standard diffusion-weighted imaging, 2D and 3D turbo spin echo, 2D and 3D gradient echo and susceptibility-weighted imaging of the brain (10 sequences) at 3 T and 7 T. The subgroups comprised patients with either lesional (n = 5) or nonlesional (n = 4) epilepsy, intracerebral tumors (n = 11), demyelinating disease (n = 11) (relapsing-remitting multiple sclerosis [MS, n = 9], secondary progressive MS [n = 1], demyelinating disease not further specified [n = 1]), or chronic cerebrovascular disorders [n = 9]). For quantitative analysis, SNR and CNR were determined. For a semiquantitative assessment of the diagnostic confidence, a 10-point scale diagnostic confidence score (DCS) was applied. Two experienced radiologists with additional qualification in neuroradiology independently assessed, blinded to the field strength, 3 pathology-specific imaging criteria in each of the 4 disease groups and rated their diagnostic confidence. The overall image quality was semiquantitatively assessed using a 4-point scale taking into account whether diagnostic decision making was hampered by artifacts or not. RESULTS Without correction for spatial resolution, SNR was higher at 3 T except in the T2 SPACE 3D, DWI single shot, and DIR SPACE 3D sequences. The SNR corrected by the ratio of 3 T/7 T voxel sizes was higher at 7 T than at 3 T in 10 of 11 sequences (all except for T1 MP2RAGE 3D).In CNR, there was a wide variation between sequences and patient cohorts, but average CNR values were broadly similar at 3 T and 7 T.DCS values for all 4 pathologic entities were higher at 7 T than at 3 T. The DCS was significantly higher at 7 T for diagnosis and exclusion of cortical lesions in vascular disease. A tendency to higher DCS at 7 T for cortical lesions in MS was observed, and for the depiction of a central vein and iron deposits within MS lesions. Despite motion artifacts, DCS values were higher at 7 T for the diagnosis and exclusion of hippocampal sclerosis in mesial temporal lobe epilepsy (improved detection of the hippocampal subunits). Interrater agreement was 69.7% at 3 T and 93.3% at 7 T. There was no significant difference in the overall image quality score between 3 T and 7 T taking into account whether diagnostic decision making was hampered by artifacts or not. CONCLUSIONS Ultra-high-field magnetic resonance imaging at 7 T compared with 3 T yielded an improved diagnostic confidence in the most frequently encountered neurologic disorders. Higher spatial resolution and contrast were identified as the main contributory factors.
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Affiliation(s)
- Elisabeth Springer
- From the *High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria; †Support Center of Advanced Neuroimaging, University Institute for Diagnostic and Interventional Neuroradiology, University Hospital Bern and Inselspital, University of Bern, Bern, Switzerland; ‡Siemens Healthcare Pty Ltd Australia, Imaging and Therapy Systems, Magnetic Resonance, Macquarie Park, New South Wales, Australia; §Siemens Healthcare, Erlangen, Germany; and ∥CD Laboratory for Molecular Clinical MR Imaging, Vienna, Austria
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Valkovič L, Chmelík M, Krššák M. In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism. Anal Biochem 2017; 529:193-215. [PMID: 28119063 PMCID: PMC5478074 DOI: 10.1016/j.ab.2017.01.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 01/18/2023]
Abstract
In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy (31P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of 31P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry. This paper presents a methodological overview of the 31P-MR techniques that can be used for basic, physiological, or clinical research of human skeletal muscle and liver in vivo. Practical issues of 31P-MRS experiments and examples of potential applications are also provided. As signal localization is essential for liver 31P-MRS and is important for dynamic muscle examinations as well, typical localization strategies for 31P-MR are also described.
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Affiliation(s)
- Ladislav Valkovič
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Oxford, United Kingdom; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Marek Chmelík
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Institute for Clinical Molecular MRI in Musculoskeletal System, Karl Landsteiner Society, Vienna, Austria
| | - Martin Krššák
- High-field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria; Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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18
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Valkovič L, Chmelík M, Meyerspeer M, Gagoski B, Rodgers CT, Krššák M, Andronesi OC, Trattnig S, Bogner W. Dynamic 31 P-MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T. NMR IN BIOMEDICINE 2016; 29:1825-1834. [PMID: 27862510 PMCID: PMC5132121 DOI: 10.1002/nbm.3662] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/19/2016] [Accepted: 09/28/2016] [Indexed: 05/06/2023]
Abstract
Phosphorus MRSI (31 P-MRSI) using a spiral-trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle. The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunteers, who performed a plantar flexion exercise inside a whole-body 7 T MR scanner using an MR-compatible ergometer and a surface coil. In five volunteers the knee was flexed (~60°) to shift the major workload from the gastrocnemii to the soleus muscle. Spiral-encoded MRSI provided 16-25 times faster mapping with a better point spread function than elliptical phase-encoded MRSI with the same matrix size. The inevitable trade-off for the increased temporal resolution was a reduced signal-to-noise ratio, but this was acceptable. The phosphocreatine (PCr) depletion caused by exercise at 0° knee angulation was significantly higher in both gastrocnemii than in the soleus (i.e. 64.8 ± 19.6% and 65.9 ± 23.6% in gastrocnemius lateralis and medialis versus 15.3 ± 8.4% in the soleus). Spiral-encoded 31 P-MRSI is a powerful tool for dynamic mapping of exercising muscle oxidative metabolism, including localized assessment of PCr concentrations, pH and maximal oxidative flux with high temporal and spatial resolution.
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Affiliation(s)
- Ladislav Valkovič
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
- Department of Imaging Methods, Institute of Measurement ScienceSlovak Academy of SciencesBratislavaSlovakia
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUK
| | - Marek Chmelík
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Martin Meyerspeer
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Borjan Gagoski
- Fetal Neonatal Neuroimaging and Developmental Science CenterBoston Children's HospitalBostonMassachusettsUSA
| | - Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR)University of OxfordOxfordUK
| | - Martin Krššák
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Ovidiu C. Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Siegfried Trattnig
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Wolfgang Bogner
- High‐Field MR CentreMedical University of ViennaViennaAustria
- Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
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Trattnig S, Bogner W, Gruber S, Szomolanyi P, Juras V, Robinson S, Zbýň Š, Haneder S. Clinical applications at ultrahigh field (7 T). Where does it make the difference? NMR IN BIOMEDICINE 2016; 29:1316-34. [PMID: 25762432 DOI: 10.1002/nbm.3272] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/20/2015] [Accepted: 01/22/2015] [Indexed: 05/11/2023]
Abstract
Presently, three major MR vendors provide commercial 7-T units for clinical research under ethical permission, with the number of operating 7-T systems having increased to over 50. This rapid increase indicates the growing interest in ultrahigh-field MRI because of improved clinical results with regard to morphological as well as functional and metabolic capabilities. As the signal-to-noise ratio scales linearly with the field strength (B0 ) of the scanner, the most obvious application at 7 T is to obtain higher spatial resolution in the brain, musculoskeletal system and breast. Of specific clinical interest for neuro-applications is the cerebral cortex at 7 T, for the detection of changes in cortical structure as a sign of early dementia, as well as for the visualization of cortical microinfarcts and cortical plaques in multiple sclerosis. In the imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology can be visualized with excellent resolution. The dynamic and static blood oxygenation level-dependent contrast increases linearly with the field strength, which significantly improves the pre-surgical evaluation of eloquent areas before tumor removal. Using susceptibility-weighted imaging, the plaque-vessel relationship and iron accumulation in multiple sclerosis can be visualized for the first time. Multi-nuclear clinical applications, such as sodium imaging for the evaluation of repair tissue quality after cartilage transplantation and (31) P spectroscopy for the differentiation between non-alcoholic benign liver disease and potentially progressive steatohepatitis, are only possible at ultrahigh fields. Although neuro- and musculoskeletal imaging have already demonstrated the clinical superiority of ultrahigh fields, whole-body clinical applications at 7 T are still limited, mainly because of the lack of suitable coils. The purpose of this article was therefore to review the clinical studies that have been performed thus far at 7 T, compared with 3 T, as well as those studies performed at 7 T that cannot be routinely performed at 3 T. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- CD Laboratory for Clinical Molecular MR Imaging
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Stephan Gruber
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Pavol Szomolanyi
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Department of Imaging Methods, Institute of Measurement Sciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Vladimir Juras
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Department of Imaging Methods, Institute of Measurement Sciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Simon Robinson
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Štefan Zbýň
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Stefan Haneder
- Vascular and Abdominal Imaging, Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany
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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.
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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
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Chmelik M, Považan M, Krššák M, Gruber S, Tkačov M, Trattnig S, Bogner W. In vivo (31)P magnetic resonance spectroscopy of the human liver at 7 T: an initial experience. NMR IN BIOMEDICINE 2014; 27:478-85. [PMID: 24615903 DOI: 10.1002/nbm.3084] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 12/11/2013] [Accepted: 01/07/2014] [Indexed: 05/12/2023]
Abstract
Phosphorus ((31) P) MRS is a powerful tool for the non-invasive investigation of human liver metabolism. Four in vivo (31) P localization approaches (single voxel image selected in vivo spectroscopy (3D-ISIS), slab selective 1D-ISIS, 2D chemical shift imaging (CSI), and 3D-CSI) with different voxel volumes and acquisition times were demonstrated in nine healthy volunteers. Localization techniques provided comparable signal-to-noise ratios normalized for voxel volume and acquisition time differences, Cramer-Rao lower bounds (8.7 ± 3.3%1D-ISIS , 7.6 ± 2.5%3D-ISIS , 8.6 ± 4.2%2D-CSI , 10.3 ± 2.7%3D-CSI ), and linewidths (50 ± 24 Hz1D-ISIS , 34 ± 10 Hz3D-ISIS , 33 ± 10 Hz2D-CSI , 34 ± 11 Hz3D-CSI ). Longitudinal (T1 ) relaxation times of human liver metabolites at 7 T were assessed by 1D-ISIS inversion recovery in the same volunteers (n = 9). T1 relaxation times of hepatic (31) P metabolites at 7 T were the following: phosphorylethanolamine - 4.41 ± 1.55 s; phosphorylcholine - 3.74 ± 1.31 s; inorganic phosphate - 0.70 ± 0.33 s; glycerol 3-phosphorylethanolamine - 6.19 ± 0.91 s; glycerol 3-phosphorylcholine - 5.94 ± 0.73 s; γ-adenosine triphosphate (ATP) - 0.50 ± 0.08 s; α-ATP - 0.46 ± 0.07 s; β-ATP - 0.56 ± 0.07 s. The improved spectral resolution at 7 T enabled separation of resonances in the phosphomonoester and phosphodiester spectral region as well as nicotinamide adenine dinucleotide and uridine diphosphoglucose signals. An additional resonance at 2.06 ppm previously assigned to phosphoenolpyruvate or phosphatidylcholine is also detectable. These are the first (31) P metabolite relaxation time measurements at 7 T in human liver, and they will help in the exploration of new, exciting questions in metabolic research with 7 T MR.
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Affiliation(s)
- Marek Chmelik
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
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Valkovič L, Gajdošík M, Traussnigg S, Wolf P, Chmelík M, Kienbacher C, Bogner W, Krebs M, Trauner M, Trattnig S, Krššák M. Application of localized ³¹P MRS saturation transfer at 7 T for measurement of ATP metabolism in the liver: reproducibility and initial clinical application in patients with non-alcoholic fatty liver disease. Eur Radiol 2014; 24:1602-9. [PMID: 24647824 DOI: 10.1007/s00330-014-3141-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 02/10/2014] [Accepted: 02/27/2014] [Indexed: 12/27/2022]
Abstract
OBJECTIVES Saturation transfer (ST) phosphorus MR spectroscopy ((31)P MRS) enables in vivo insight into energy metabolism and thus could identify liver conditions currently diagnosed only by biopsy. This study assesses the reproducibility of the localized (31)P MRS ST in liver at 7 T and tests its potential for noninvasive differentiation of non-alcoholic fatty liver (NAFL) and steatohepatitis (NASH). METHODS After the ethics committee approval, reproducibility of the localized (31)P MRS ST at 7 T and the biological variation of acquired hepato-metabolic parameters were assessed in healthy volunteers. Subsequently, 16 suspected NAFL/NASH patients underwent MRS measurements and diagnostic liver biopsy. The Pi-to-ATP exchange parameters were compared between the groups by a Mann-Whitney U test and related to the liver fat content estimated by a single-voxel proton ((1)H) MRS, measured at 3 T. RESULTS The mean exchange rate constant (k) in healthy volunteers was 0.31 ± 0.03 s(-1) with a coefficient of variation of 9.0 %. Significantly lower exchange rates (p < 0.01) were found in NASH patients (k = 0.17 ± 0.04 s(-1)) when compared to healthy volunteers, and NAFL patients (k = 0.30 ± 0.05 s(-1)). Significant correlation was found between the k value and the liver fat content (r = 0.824, p < 0.01). CONCLUSIONS Our data suggest that the (31)P MRS ST technique provides a tool for gaining insight into hepatic ATP metabolism and could contribute to the differentiation of NAFL and NASH. KEY POINTS • 1D localized (31) P MRS saturation transfer in the liver is reproducible at 7 T • NASH patients have decreased hepatic Pi-to-ATP exchange rate • In this study, hepatic metabolic activity correlates with liver fat content.
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Affiliation(s)
- Ladislav Valkovič
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
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Valkovič L, Bogner W, Gajdošík M, Považan M, Kukurová IJ, Krššák M, Gruber S, Frollo I, Trattnig S, Chmelík M. One-dimensional image-selected in vivo spectroscopy localized phosphorus saturation transfer at 7T. Magn Reson Med 2014; 72:1509-15. [PMID: 24470429 DOI: 10.1002/mrm.25058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 10/30/2013] [Accepted: 11/05/2013] [Indexed: 01/07/2023]
Abstract
PURPOSE To evaluate the feasibility of a one-dimensional image-selected in vivo spectroscopy (1D-ISIS) saturation transfer (ST) sequence at 7T for localized in vivo measurements of energy metabolism in different tissues in clinically reasonable examination times. METHODS The performance of a gradient offset independent adiabacity-based 1D-ISIS localization was tested on phantom and the localized ST sequence was compared with the nonlocalized version in vivo. We performed localized measurements of basal metabolism of human liver and different muscle groups of the calf. Localized ST experiments took 15-25 minutes. RESULTS The selectivity of the 1D-ISIS sequence was 81.63% and the outer volume suppression was 97.57%. The ST parameters acquired with the 1D-ISIS sequence and with the nonlocalized acquisition in the muscle were not statistically different. The forward rate constants for phosphocreatine (PCr)-adenosine triphosphate (ATP) and inorganic phosphate (Pi)-ATP exchange reactions were measured in the soleus (kCK = 0.30 ± 0.06 s(-1) and kATP = 0.11 ± 0.02 s(-1) , respectively) and in the medial gastrocnemius (kCK = 0.27 ± 0.06 s(-1) and kATP = 0.09 ± 0.03s(-1) , respectively) in 15 minutes per muscle group. The corresponding fluxes were FCK = 6.26 ± 1.28 μmol/g/s, FATP = 0.22 ± 0.05 μmol/g/s and FCK = 6.29 ± 1.66 μmol/g/s, FATP = 0.21 ± 0.07 μmol/g/s, for soleus and gastrocnemius, respectively. The hepatic ATP synthesis measurement was feasible in 24 minutes. CONCLUSION The fast assessment of PCr-ATP and Pi-ATP exchange rates at 7T makes the 1D-ISIS ST sequence a promising tool for examining local resting-state metabolism in clinically acceptable measurement times.
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Affiliation(s)
- Ladislav Valkovič
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
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Filippi M, Evangelou N, Kangarlu A, Inglese M, Mainero C, Horsfield MA, Rocca MA. Ultra-high-field MR imaging in multiple sclerosis. J Neurol Neurosurg Psychiatry 2014; 85:60-6. [PMID: 23813636 DOI: 10.1136/jnnp-2013-305246] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In multiple sclerosis (MS), MRI is the most important paraclinical tool used to inform diagnosis and for monitoring disease evolution, either natural or modified by treatment. The increased availability of ultra-high-field magnets (7 Tesla or higher) gives rise to questions about the main benefits of and challenges for their use in patients with MS. The main advantages of ultra-high-field MRI are the improved signal-to-noise ratio, greater chemical shift dispersion, and improved contrast due to magnetic susceptibility variations, which lead to increased sensitivity to the heterogeneous pathological substrates of the disease. At present, ultra-high-field MRI is mainly used to improve our understanding of MS pathogenesis. This review discusses the main achievements that have so far come from the use of these scanners, which are: better visualisation of white matter lesions and their morphological characteristics; an improvement in the ability to visualise grey matter lesions and their exact location; the quantification of 'novel' metabolites which may have a role in axonal degeneration; and greater sensitivity to iron accumulation. The application of ultra-high-field systems in standard clinical practice is still some way off since their role in the diagnostic work-up of patients at presentation with clinically isolated syndromes, or in monitoring disease progression or treatment response in patients with definite MS, needs to be established. Additional challenges remain in the development of morphological, quantitative and functional imaging methods at these field strengths, techniques which may ultimately lead to novel biomarkers for monitoring disease evolution and treatment response.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Division of Neuroscience, Institute of Experimental Neurology, , San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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Chang G, Deniz CM, Honig S, Egol K, Regatte RR, Zhu Y, Sodickson DK, Brown R. MRI of the hip at 7T: feasibility of bone microarchitecture, high-resolution cartilage, and clinical imaging. J Magn Reson Imaging 2013; 39:1384-93. [PMID: 24115554 DOI: 10.1002/jmri.24305] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 06/18/2013] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To demonstrate the feasibility of performing bone microarchitecture, high-resolution cartilage, and clinical imaging of the hip at 7T. MATERIALS AND METHODS This study had Institutional Review Board approval. Using an 8-channel coil constructed in-house, we imaged the hips of 15 subjects on a 7T magnetic resonance imaging (MRI) scanner. We applied: 1) a T1-weighted 3D fast low angle shot (3D FLASH) sequence (0.23 × 0.23 × 1-1.5 mm(3) ) for bone microarchitecture imaging; 2) T1-weighted 3D FLASH (water excitation) and volumetric interpolated breath-hold examination (VIBE) sequences (0.23 × 0.23 × 1.5 mm(3) ) with saturation or inversion recovery-based fat suppression for cartilage imaging; 3) 2D intermediate-weighted fast spin-echo (FSE) sequences without and with fat saturation (0.27 × 0.27 × 2 mm) for clinical imaging. RESULTS Bone microarchitecture images allowed visualization of individual trabeculae within the proximal femur. Cartilage was well visualized and fat was well suppressed on FLASH and VIBE sequences. FSE sequences allowed visualization of cartilage, the labrum (including cartilage and labral pathology), joint capsule, and tendons. CONCLUSION This is the first study to demonstrate the feasibility of performing a clinically comprehensive hip MRI protocol at 7T, including high-resolution imaging of bone microarchitecture and cartilage, as well as clinical imaging.
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Affiliation(s)
- Gregory Chang
- Department of Radiology, NYU Langone Medical Center, Center for Musculoskeletal Care, New York, New York, USA
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Rodgers CT, Clarke WT, Snyder C, Vaughan JT, Neubauer S, Robson MD. Human cardiac 31P magnetic resonance spectroscopy at 7 Tesla. Magn Reson Med 2013; 72:304-15. [PMID: 24006267 PMCID: PMC4106879 DOI: 10.1002/mrm.24922] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 07/22/2013] [Accepted: 07/23/2013] [Indexed: 01/02/2023]
Abstract
Purpose Phosphorus magnetic resonance spectroscopy (31P-MRS) affords unique insight into cardiac energetics but has a low intrinsic signal-to-noise ratio (SNR) in humans. Theory predicts an increased 31P-MRS SNR at 7T, offering exciting possibilities to better investigate cardiac metabolism. We therefore compare the performance of human cardiac 31P-MRS at 7T to 3T, and measure T1s for 31P metabolites at 7T. Methods Matched 31P-MRS data were acquired at 3T and 7T, on nine normal volunteers. A novel Look-Locker CSI acquisition and fitting approach was used to measure T1s on six normal volunteers. Results T1s in the heart at 7T were: phosphocreatine (PCr) 3.05 ± 0.41s, γ-ATP 1.82 ± 0.09s, α-ATP 1.39 ± 0.09s, β-ATP 1.02 ± 0.17s and 2,3-DPG (2,3-diphosphoglycerate) 3.05 ± 0.41s (N = 6). In the field comparison (N = 9), PCr SNR increased 2.8× at 7T relative to 3T, the Cramer-Ráo uncertainty (CRLB) in PCr concentration decreased 2.4×, the mean CRLB in PCr/ATP decreased 2.7× and the PCr/ATP SD decreased 2×. Conclusion Cardiac 31P-MRS at 7T has higher SNR and the spectra can be quantified more precisely than at 3T. Cardiac 31P T1s are shorter at 7T than at 3T. We predict that 7T will become the field strength of choice for cardiac 31P-MRS. Magn Reson Med 72:304–315, 2014. © 2013 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Christopher T Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
- * Correspondence to: Christopher T. Rodgers, D.Phil., Oxford Centre for Clinical Magnetic Resonance Research (OCMR), Level 0, John Radcliffe Hospital, Oxford, OX3 9DU United Kingdom. E-mail:
| | - William T Clarke
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Carl Snyder
- Center for Magnetic Resonance Research, University of Minnesota2021 Sixth Street SE, Minneapolis, Minnesota, USA.
| | - J Thomas Vaughan
- Center for Magnetic Resonance Research, University of Minnesota2021 Sixth Street SE, Minneapolis, Minnesota, USA.
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of OxfordLevel 0, John Radcliffe Hospital, Oxford, United Kingdom
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Noninvasive monitoring of training induced muscle adaptation with 31P-MRS: fibre type shifts correlate with metabolic changes. BIOMED RESEARCH INTERNATIONAL 2013; 2013:417901. [PMID: 23998123 PMCID: PMC3749530 DOI: 10.1155/2013/417901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/02/2013] [Accepted: 06/11/2013] [Indexed: 11/23/2022]
Abstract
Purpose. To evaluate training induced metabolic changes noninvasively with 31P magnetic resonance spectroscopy (31P-MRS) for measuring muscle fibre type adaptation.
Methods. Eleven volunteers underwent a 24-week training, consisting of speed-strength, endurance, and detraining (each 8 weeks). Prior to and following each training period, needle biopsies and 31P-MRS of the resting gastrocnemius muscle were performed. Fibre type distribution was analyzed histologically and tested for correlation with the ratios of high energy phosphates ([PCr]/[Pi], [PCr]/[βATP] and [PCr + Pi]/[βATP]). The correlation between the changes of the 31P-MRS parameters during training and the resulting changes in fibre composition were also analysed. Results. We observed an increased type-II-fibre proportion after speed-strength and detraining. After endurance training the percentage of fast-twitch fibres was reduced. The progression of the [PCr]/[Pi]-ratio was similar to that of the fast-twitch fibres during the training. We found a correlation between the type-II-fibre proportion and [PCr]/[Pi] (r = 0.70, P < 0.01) or [PCr]/[βATP] (r = 0.69, P < 0.01); the correlations between its changes (delta) and the fibre-shift were significant as well (delta[PCr]/[Pi] r = 0.66, delta[PCr]/[βATP] r = 0.55, P < 0.01). Conclusion. Shifts in fibre type composition and high energy phosphate metabolite content covary in human gastrocnemius muscle. Therefore 31P-MRS might be a feasible method for noninvasive monitoring of exercise-induced fibre type transformation.
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Parasoglou P, Xia D, Chang G, Convit A, Regatte RR. Three-dimensional mapping of the creatine kinase enzyme reaction rate in muscles of the lower leg. NMR IN BIOMEDICINE 2013; 26:1142-51. [PMID: 23436474 PMCID: PMC3744626 DOI: 10.1002/nbm.2928] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/06/2012] [Accepted: 01/07/2013] [Indexed: 05/25/2023]
Abstract
Phosphorus ((31) P) magnetization transfer (MT) techniques enable the non-invasive measurement of metabolic turnover rates of important enzyme-catalyzed reactions, such as the creatine kinase reaction (CK), a major transducing reaction involving adenosine triphosphate and phosphocreatine. Alteration in the kinetics of the CK reaction rate appears to play a central role in many disease states. In this study, we developed and implemented at ultra-high field (7T) a novel three-dimensional (31) P-MT imaging sequence that maps the kinetics of CK in the entire volume of the lower leg at relatively high resolution (0.52 mL voxel size), and within acquisition times that can be tolerated by patients (below 60 min). We tested the sequence on five healthy and two clinically diagnosed type 2 diabetic subjects. Overall, we obtained measurements that are in close agreement with measurements reported previously using spectroscopic methods. Importantly, our spatially resolved method allowed us to measure local CK reaction rate constants and metabolic fluxes in individual muscles in a non-invasive manner. Furthermore, it allowed us to detect variations of the CK rates of different muscles, which would not have been possible using unlocalized MRS methods. The results of this work suggest that 3D mapping of the CK reaction rates and metabolic fluxes can be achieved in the skeletal muscle in vivo at relatively high spatial resolution and with acquisition times well tolerated by patients. The ability to measure bioenergetics simultaneously in large areas of muscles will bring new insights into possible heterogeneous patterns of muscle metabolism associated with several diseases and serve as a valuable tool for monitoring the efficacy of interventions.
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Affiliation(s)
- Prodromos Parasoglou
- Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Department of Radiology, Center for Biomedical Imaging, New York University Langone Medical Center, New York, NY 10016, USA.
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Parasoglou P, Xia D, Chang G, Regatte RR. Dynamic three-dimensional imaging of phosphocreatine recovery kinetics in the human lower leg muscles at 3T and 7T: a preliminary study. NMR IN BIOMEDICINE 2013; 26:348-56. [PMID: 23065754 PMCID: PMC3696475 DOI: 10.1002/nbm.2866] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 08/20/2012] [Accepted: 08/22/2012] [Indexed: 05/11/2023]
Abstract
The rate of phosphocreatine (PCr) resynthesis after physical exercise has been extensively studied with phosphorus (³¹P)-MRS. Previous studies have used small surface coils that were limited to measuring one superficial muscle per experiment. This study focuses on the development and implementation of a spectrally selective three-dimensional turbo spin echo (3D-TSE) sequence at 3T and 7T with temporal resolution of 24 s, using two geometrically identical volume coils. We acquired imaging data of PCr recovery from four healthy volunteers and one diabetic patient, who performed plantar flexions using resistance bands. We segmented the anatomical regions of six different muscles from the lower leg, namely the gastrocnemius [lateral (GL) and medial (GM)], the tibialis [anterior (TA) and posterior (TP)], the soleus (S) and the peroneus (P) and measured the local PCr resynthesis rate constants. During the same examination, we also acquired unlocalized (³¹P-MRS data at a temporal resolution of 6 s. At 3T, the PCr resynthesis rate constants were measured at 25.4 ± 3.7 s [n = 4, mean ± standard deviation (SD)] using the MRS method and 25.6 ± 4.4 s using the MRI method. At 7T, the measured rates were 26.4 ± 3.2 s and 26.2 ± 4.7 s for MRS and MRI. Using our imaging method, we measured the local PCr resynthesis rate constants in six individual muscles of the lower leg (min/max 20.2/31.7 ). The recovery rate constants measured for the diabetic patient were 55.5 s (MRS) and 52.7 s (MRI). The successful implementation of our 3D-method suggests that imaging is possible at both fields with a relatively high spatial resolution (voxel size: 4.2 mL at 3T and 1.6 mL at 7T) using volume coils and that local PCr resynthesis rates can be obtained in a single measurement. The advantage of the imaging method is that it can highlight differences in PCr resynthesis rates between different muscles in a single measurement in order to study spatial gradients of metabolic properties of diseased states for which very little is currently known.
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Affiliation(s)
- Prodromos Parasoglou
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY, USA.
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Parasoglou P, Xia D, Chang G, Regatte RR. 3D-mapping of phosphocreatine concentration in the human calf muscle at 7 T: comparison to 3 T. Magn Reson Med 2013; 70:1619-25. [PMID: 23390003 DOI: 10.1002/mrm.24616] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/27/2012] [Accepted: 12/05/2012] [Indexed: 01/09/2023]
Abstract
PURPOSE The development and implementation of a spectrally selective 3D-Turbo Spin Echo sequence for quantitative mapping of phosphocreatine (PCr) concentration in different muscles of the lower leg of healthy volunteers both at 3 T and 7 T. METHODS Nine healthy volunteers were recruited, all of whom where scanned at 3 T and 7 T. Three dimensional PCr concentration maps were obtained after images were corrected for B1 inhomogeneities, T1 relaxation weighting, and partial volume of fatty tissue in the muscles. Two volunteers performed plantar flexions inside the magnet, and the oxidative capacity of their muscles was estimated. RESULTS Three dimensional PCr concentration maps were obtained, with full muscle coverage and nominal voxel size of 0.52 mL at both fields. At 7 T a 2.7-fold increase of signal-to-noise ratio was achieved compared to 3 T. CONCLUSION Imaging (31) P metabolites at 7 T allowed for significant increase in signal to noise ratio compared to imaging at 3 T, while quantification of the PCr concentration remained unaffected. The importance of such an increase in signal-to-noise ratio is 2-fold, first higher resolution images with reduced partial volume effects can be acquired, and second multiple measurements such as dynamic imaging of PCr post-exercise, (31) P magnetization transfer, or other (1) H measurements, can be acquired in a single imaging session.
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Affiliation(s)
- Prodromos Parasoglou
- Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, New York, USA
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31
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Chmelík M, Kukurová IJ, Gruber S, Krššák M, Valkovič L, Trattnig S, Bogner W. Fully adiabatic 31P 2D-CSI with reduced chemical shift displacement error at 7 T--GOIA-1D-ISIS/2D-CSI. Magn Reson Med 2012; 69:1233-44. [PMID: 22714782 DOI: 10.1002/mrm.24363] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 04/24/2012] [Accepted: 05/14/2012] [Indexed: 12/24/2022]
Abstract
A fully adiabatic phosphorus (31P) two-dimensional (2D) chemical shift spectroscopic imaging sequence with reduced chemical shift displacement error for 7 T, based on 1D-image-selected in vivo spectroscopy, combined with 2D-chemical shift spectroscopic imaging selection, was developed. Slice-selective excitation was achieved by a spatially selective broadband GOIA-W(16,4) inversion pulse with an interleaved subtraction scheme before nonselective adiabatic excitation, and followed by 2D phase encoding. The use of GOIA-W(16,4) pulses (bandwidth 4.3-21.6 kHz for 10-50 mm slices) reduced the chemical shift displacement error in the slice direction ∼1.5-7.7 fold, compared to conventional 2D-chemical shift spectroscopic imaging with Sinc3 selective pulses (2.8 kHz). This reduction was experimentally demonstrated with measurements of an MR spectroscopy localization phantom and with experimental evaluation of pulse profiles. In vivo experiments in clinically acceptable measurement times were demonstrated in the calf muscle (nominal voxel volume, 5.65 ml in 6 min 53 s), brain (10 ml, 6 min 32 s), and liver (8.33 ml, 8 min 14 s) of healthy volunteers at 7 T. High reproducibility was found in the calf muscle at 7 T. In combination with adiabatic excitation, this sequence is insensitive to the B1 inhomogeneities associated with surface coils. This sequence, which is termed GOIA-1D-ISIS/2D-CSI (goISICS), has the potential to be applied in both clinical research and in the clinical routine.
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Affiliation(s)
- M Chmelík
- MR Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria
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Advanced MR methods at ultra-high field (7 Tesla) for clinical musculoskeletal applications. Eur Radiol 2012; 22:2338-46. [DOI: 10.1007/s00330-012-2508-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/02/2012] [Accepted: 05/04/2012] [Indexed: 12/16/2022]
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Moser E, Stahlberg F, Ladd ME, Trattnig S. 7-T MR--from research to clinical applications? NMR IN BIOMEDICINE 2012; 25:695-716. [PMID: 22102481 DOI: 10.1002/nbm.1794] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 08/25/2011] [Accepted: 08/31/2011] [Indexed: 05/31/2023]
Abstract
Over 20,000 MR systems are currently installed worldwide and, although the majority operate at magnetic fields of 1.5 T and below (i.e. about 70%), experience with 3-T (in high-field clinical diagnostic imaging and research) and 7-T (research only) human MR scanners points to a future in functional and metabolic MR diagnostics. Complementary to previous studies, this review attempts to provide an overview of ultrahigh-field MR research with special emphasis on emerging clinical applications at 7 T. We provide a short summary of the technical development and the current status of installed MR systems. The advantages and challenges of ultrahigh-field MRI and MRS are discussed with special emphasis on radiofrequency inhomogeneity, relaxation times, signal-to-noise improvements, susceptibility effects, chemical shifts, specific absorption rate and other safety issues. In terms of applications, we focus on the topics most likely to gain significantly from 7-T MR, i.e. brain imaging and spectroscopy and musculoskeletal imaging, but also body imaging, which is particularly challenging. Examples are given to demonstrate the advantages of susceptibility-weighted imaging, time-of-flight MR angiography, high-resolution functional MRI, (1)H and (31)P MRSI in the human brain, sodium and functional imaging of cartilage and the first results (and artefacts) using an eight-channel body array, suggesting future areas of research that should be intensified in order to fully explore the potential of 7-T MR systems for use in clinical diagnosis.
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Affiliation(s)
- Ewald Moser
- Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
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Parasoglou P, Xia D, Regatte RR. Spectrally selective 3D TSE imaging of phosphocreatine in the human calf muscle at 3 T. Magn Reson Med 2012; 69:812-7. [PMID: 22499078 DOI: 10.1002/mrm.24288] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/14/2012] [Accepted: 03/16/2012] [Indexed: 12/29/2022]
Abstract
Quantitative information about concentrations of several metabolites in human skeletal muscle can be obtained through localized (31)P magnetic resonance spectroscopy methods. However, these methods have shortcomings: long acquisition times, limited volume coverage, and coarse resolution. Significantly higher spatial and temporal resolution of imaging of single metabolites can be achieved through spectrally selective three-dimensional imaging methods. This study reports the implementation of a three-dimensional spectrally selective turbo spin-echo sequence, on a 3T clinical system, to map the concentration of phosphocreatine in the human calf muscle with significantly increased spatial resolution and in a clinically feasible scan time. Absolute phosphocreatine quantification was performed with the use of external phantoms after relaxation and flip angle correction of the turbo spin-echo voxel signal. The mean ± standard deviation of the phosphocreatine concentration measured in five healthy volunteers was 29.4 ± 2.5 mM with signal-to-noise ratio of 14:1 and voxel size of 0.52 mL.
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Affiliation(s)
- Prodromos Parasoglou
- Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, New York 10016, USA.
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Valkovič L, Chmelík M, Just Kukurova I, Krššák M, Gruber S, Frollo I, Trattnig S, Bogner W. Time-resolved phosphorous magnetization transfer of the human calf muscle at 3 T and 7 T: a feasibility study. Eur J Radiol 2011; 82:745-51. [PMID: 22154589 DOI: 10.1016/j.ejrad.2011.09.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 09/19/2011] [Indexed: 11/26/2022]
Abstract
Phosphorous ((31)P) magnetization transfer (MT) experiments enable the non-invasive investigation of human muscle metabolism in various physiological and pathological conditions. The purpose of our study was to investigate the feasibility of time-resolved MT, and to compare the results of MT experiments at 3 T and 7 T. Six healthy volunteers were examined on a 3T and a 7 T MR scanner using the same setup and identical measurement protocols. In the calf muscle of all volunteers, four separate MT experiments (each ∼10 min duration) were performed in one session. The forward rate constant of the ATP synthesis reaction (kATP) and creatine kinase reaction (kCK), as well as corresponding metabolic fluxes (FATP, FCK), were estimated. A comparison of these exchange parameters, apparent T₁s, data quality, quantification precision, and reproducibility was performed. The data quality and reproducibility of the same MT experiments at 7 T was significantly higher (i.e., kATP 2.7 times higher and kCK 3.4 times higher) than at 3 T (p<0.05). The values for kATP (p=0.35) and kCK (p=0.09) at both field strengths were indistinguishable. Even a single MT experiment at 7 T provided better data quality than did a 4 times-longer MT experiment at 3T. The minimal time-resolution to reliably quantify both FATP and FCK at 7 T was ∼6 min. Our results show that MT experiments at 7 T can be at least 4 times faster than 3 T MT experiments and still provide significantly better quantification. This enables time-resolved MT experiments for the observation of slow metabolic changes in the human calf muscle at 7 T.
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Affiliation(s)
- Ladislav Valkovič
- MR Center of Excellence, Department of Radiology, Medical University Vienna, A-1090 Wien, Lazarettgasse 14, Austria
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