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Okada T, Fujimoto K, Fushimi Y, Akasaka T, Thuy DHD, Shima A, Sawamoto N, Oishi N, Zhang Z, Funaki T, Nakamoto Y, Murai T, Miyamoto S, Takahashi R, Isa T. Neuroimaging at 7 Tesla: a pictorial narrative review. Quant Imaging Med Surg 2022; 12:3406-3435. [PMID: 35655840 PMCID: PMC9131333 DOI: 10.21037/qims-21-969] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/05/2022] [Indexed: 01/26/2024]
Abstract
Neuroimaging using the 7-Tesla (7T) human magnetic resonance (MR) system is rapidly gaining popularity after being approved for clinical use in the European Union and the USA. This trend is the same for functional MR imaging (MRI). The primary advantages of 7T over lower magnetic fields are its higher signal-to-noise and contrast-to-noise ratios, which provide high-resolution acquisitions and better contrast, making it easier to detect lesions and structural changes in brain disorders. Another advantage is the capability to measure a greater number of neurochemicals by virtue of the increased spectral resolution. Many structural and functional studies using 7T have been conducted to visualize details in the white matter and layers of the cortex and hippocampus, the subnucleus or regions of the putamen, the globus pallidus, thalamus and substantia nigra, and in small structures, such as the subthalamic nucleus, habenula, perforating arteries, and the perivascular space, that are difficult to observe at lower magnetic field strengths. The target disorders for 7T neuroimaging range from tumoral diseases to vascular, neurodegenerative, and psychiatric disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, major depressive disorder, and schizophrenia. MR spectroscopy has also been used for research because of its increased chemical shift that separates overlapping peaks and resolves neurochemicals more effectively at 7T than a lower magnetic field. This paper presents a narrative review of these topics and an illustrative presentation of images obtained at 7T. We expect 7T neuroimaging to provide a new imaging biomarker of various brain disorders.
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Affiliation(s)
- Tomohisa Okada
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koji Fujimoto
- Department of Real World Data Research and Development, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasutaka Fushimi
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Thai Akasaka
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Dinh H. D. Thuy
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Shima
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobukatsu Sawamoto
- Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Naoya Oishi
- Medial Innovation Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Zhilin Zhang
- Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takeshi Funaki
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yuji Nakamoto
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Toshiya Murai
- Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Susumu Miyamoto
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tadashi Isa
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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2
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Improved 7 Tesla transmit field homogeneity with reduced electromagnetic power deposition using coupled Tic Tac Toe antennas. Sci Rep 2021; 11:3370. [PMID: 33564013 PMCID: PMC7873125 DOI: 10.1038/s41598-020-79807-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/26/2020] [Indexed: 12/28/2022] Open
Abstract
Recently cleared by the FDA, 7 Tesla (7 T) MRI is a rapidly growing technology that can provide higher resolution and enhanced contrast in human MRI images. However, the increased operational frequency (~ 297 MHz) hinders its full potential since it causes inhomogeneities in the images and increases the power deposition in the tissues. This work describes the optimization of an innovative radiofrequency (RF) head coil coupled design, named Tic Tac Toe, currently used in large scale human MRI scanning at 7 T; to date, this device was used in more than 1,300 neuro 7 T MRI scans. Electromagnetic simulations of the coil were performed using the finite-difference time-domain method. Numerical optimizations were used to combine the calculated electromagnetic fields produced by these antennas, based on the superposition principle, resulting in homogeneous magnetic field distributions at low levels of power deposition in the tissues. The simulations were validated in-vivo using the Tic Tac Toe RF head coil system on a 7 T MRI scanner.
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Ultra-high resolution and multi-shell diffusion MRI of intact ex vivo human brains using kT-dSTEAM at 9.4T. Neuroimage 2019; 202:116087. [DOI: 10.1016/j.neuroimage.2019.116087] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/08/2019] [Indexed: 01/07/2023] Open
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Tomi‐Tricot R, Gras V, Thirion B, Mauconduit F, Boulant N, Cherkaoui H, Zerbib P, Vignaud A, Luciani A, Amadon A. SmartPulse, a machine learning approach for calibration‐free dynamic RF shimming: Preliminary study in a clinical environment. Magn Reson Med 2019; 82:2016-2031. [DOI: 10.1002/mrm.27870] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/23/2019] [Accepted: 05/26/2019] [Indexed: 12/16/2022]
Affiliation(s)
| | - Vincent Gras
- NeuroSpin, CEA, Université Paris‐Saclay Gif‐sur‐Yvette France
| | | | | | - Nicolas Boulant
- NeuroSpin, CEA, Université Paris‐Saclay Gif‐sur‐Yvette France
| | - Hamza Cherkaoui
- Parietal, Inria Université Paris‐Saclay Gif‐sur‐Yvette France
| | - Pierre Zerbib
- Department of Radiology AP‐HP, CHU Henri Mondor Créteil France
| | | | - Alain Luciani
- Department of Radiology AP‐HP, CHU Henri Mondor Créteil France
- Université Paris‐Est Créteil Val de Marne Créteil France
- INSERM U955, Team 18, Molecular Virology and Immunology – Physiopathology and Therapeutic of Chronic Viral Hepatitis Créteil France
| | - Alexis Amadon
- NeuroSpin, CEA, Université Paris‐Saclay Gif‐sur‐Yvette France
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Sati P. Diagnosis of multiple sclerosis through the lens of ultra-high-field MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:101-109. [PMID: 29705032 PMCID: PMC6022748 DOI: 10.1016/j.jmr.2018.01.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 06/08/2023]
Abstract
The long-standing relationship between ultra-high-field (7 T) MRI and multiple sclerosis (MS) has brought new insights to our understanding of lesion evolution and its associated pathology. With the recent FDA approval of a commercially available scanner, 7 T MRI is finally entering the clinic with great expectations about its potential added value. By looking through the prism of MS diagnosis, this perspective article discusses current limitations and prospects of 7 T MRI techniques relevant to helping clinicians diagnose patients encountered in daily practice.
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Affiliation(s)
- Pascal Sati
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive MSC 1400, Building 10 Room 5C103, Bethesda, MD 20852, USA.
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6
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How to choose the right MR sequence for your research question at 7 T and above? Neuroimage 2018; 168:119-140. [DOI: 10.1016/j.neuroimage.2017.04.044] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 12/29/2022] Open
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Beqiri A, Hoogduin H, Sbrizzi A, Hajnal JV, Malik SJ. Whole-brain 3D FLAIR at 7T using direct signal control. Magn Reson Med 2018; 80:1533-1545. [PMID: 29476551 PMCID: PMC6120540 DOI: 10.1002/mrm.27149] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/02/2018] [Accepted: 02/02/2018] [Indexed: 11/10/2022]
Abstract
Purpose Image quality obtained for brain imaging at 7T can be hampered by inhomogeneities in the static magnetic field, B0, and the RF electromagnetic field, B1. In imaging sequences such as fluid‐attenuated inversion recovery (FLAIR), which is used to assess neurological disorders, these inhomogeneities cause spatial variations in signal that can reduce clinical efficacy. In this work, we aim to correct for signal inhomogeneities to ensure whole‐brain coverage with 3D FLAIR at 7T. Methods The direct signal control (DSC) framework was used to optimize channel weightings applied to the 8 transmit channels used in this work on a pulse‐by‐pulse basis through the echo train in the FLAIR sequences. 3D FLAIR brain images were acquired on 5 different subjects and compared with imaging using a quadrature‐like mode of the transmit array. Precomputed “universal” DSC solutions calculated from a separate set of 5 subjects were also explored. Results DSC consistently enabled improved imaging across all subjects, with no dropouts in signal seen over the entire brain volume, which contrasted with imaging in quadrature mode. Further, the universal DSC solutions also consistently improved imaging despite not being optimized specifically for the subject being imaged. Conclusion 3D FLAIR brain imaging at 7T is substantially improved using DSC and is able to recover regions of low signal without increasing imaging time or interecho spacing.
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Affiliation(s)
- Arian Beqiri
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom
| | - Hans Hoogduin
- Center for Image Sciences, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Alessandro Sbrizzi
- Center for Image Sciences, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Joseph V Hajnal
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom.,Centre for the Developing Brain, School of Imaging Sciences & Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom
| | - Shaihan J Malik
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom
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Vargas MI, Martelli P, Xin L, Ipek O, Grouiller F, Pittau F, Trampel R, Gruetter R, Vulliemoz S, Lazeyras F. Clinical Neuroimaging Using 7 T MRI: Challenges and Prospects. J Neuroimaging 2017; 28:5-13. [PMID: 29205628 DOI: 10.1111/jon.12481] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/02/2017] [Indexed: 01/19/2023] Open
Abstract
The aim of this article is to illustrate the principal challenges, from the medical and technical point of view, associated with the use of ultrahigh field (UHF) scanners in the clinical setting and to present available solutions to circumvent these limitations. We would like to show the differences between UHF scanners and those used routinely in clinical practice, the principal advantages, and disadvantages, the different UHFs that are ready be applied to routine clinical practice such as susceptibility-weighted imaging, fluid-attenuated inversion recovery, 3-dimensional time of flight, magnetization-prepared rapid acquisition gradient echo, magnetization-prepared 2 rapid acquisition gradient echo, and diffusion-weighted imaging, the technical principles of these sequences, and the particularities of advanced techniques such as diffusion tensor imaging, spectroscopy, and functional imaging at 7TMR. Finally, the main clinical applications in the field of the neuroradiology are discussed and the side effects are reported.
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Affiliation(s)
- Maria Isabel Vargas
- Division of Neuroradiology of Geneva University Hospitals and Geneva University, Geneva, Switzerland
| | - Pascal Martelli
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lijing Xin
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ozlem Ipek
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Frederic Grouiller
- CIBM, Department of Radiology and Medical Informatics, Geneva Hospitals and University of Geneva, Geneva, Switzerland
| | - Francesca Pittau
- Division of Neurology, Epileptology Unit, Geneva University Hospitals, Geneva, Switzerland
| | - Robert Trampel
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Rolf Gruetter
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Serge Vulliemoz
- Division of Neurology, Epileptology Unit, Geneva University Hospitals, Geneva, Switzerland
| | - Francois Lazeyras
- CIBM, Department of Radiology and Medical Informatics, Geneva Hospitals and University of Geneva, Geneva, Switzerland.,Division of Radiology of Geneva University Hospitals and CIBM, Geneva, Switzerland
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Tomi-Tricot R, Gras V, Mauconduit F, Legou F, Boulant N, Gebhardt M, Ritter D, Kiefer B, Zerbib P, Rahmouni A, Vignaud A, Luciani A, Amadon A. B1
artifact reduction in abdominal DCE-MRI using kT
-points: First clinical assessment of dynamic RF shimming at 3T. J Magn Reson Imaging 2017; 47:1562-1571. [DOI: 10.1002/jmri.25908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/09/2017] [Indexed: 11/05/2022] Open
Affiliation(s)
| | - Vincent Gras
- NeuroSpin/UNIRS, CEA, Paris-Saclay; Gif-sur-Yvette Cedex France
| | | | - François Legou
- Department of Radiology; AP-HP, CHU Henri Mondor; Cedex France
| | - Nicolas Boulant
- NeuroSpin/UNIRS, CEA, Paris-Saclay; Gif-sur-Yvette Cedex France
| | | | | | | | - Pierre Zerbib
- Department of Radiology; AP-HP, CHU Henri Mondor; Cedex France
| | - Alain Rahmouni
- Department of Radiology; AP-HP, CHU Henri Mondor; Cedex France
- Université Paris-Est Créteil Val de Marne; Créteil Cedex France
| | | | - Alain Luciani
- Department of Radiology; AP-HP, CHU Henri Mondor; Cedex France
- Université Paris-Est Créteil Val de Marne; Créteil Cedex France
- INSERM Unité U955, Equipe 18, Molecular Virology and Immunology - Physiopathology and Therapeutic of Chronic Viral Hepatitis; Créteil France
| | - Alexis Amadon
- NeuroSpin/UNIRS, CEA, Paris-Saclay; Gif-sur-Yvette Cedex France
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Niendorf T, Barth M, Kober F, Trattnig S. From ultrahigh to extreme field magnetic resonance: where physics, biology and medicine meet. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 29:309-11. [PMID: 27221262 DOI: 10.1007/s10334-016-0564-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Robert Roessle Strasse 10, 13125, Berlin, Germany.
| | - Markus Barth
- Centre for Advanced Imaging, The University of Queensland, Building 57, Research Road, St Lucia, QLD, 4072, Australia
| | - Frank Kober
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), Aix-Marseille Université, CNRS UMR7339, 13385, Marseille Cedex 05, France
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image Guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
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11
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Kraff O, Quick HH. 7T: Physics, safety, and potential clinical applications. J Magn Reson Imaging 2017; 46:1573-1589. [DOI: 10.1002/jmri.25723] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 03/17/2017] [Indexed: 12/19/2022] Open
Affiliation(s)
- Oliver Kraff
- Erwin L. Hahn Institute for MR Imaging; University of Duisburg-Essen; Essen Germany
| | - Harald H. Quick
- Erwin L. Hahn Institute for MR Imaging; University of Duisburg-Essen; Essen Germany
- High Field and Hybrid MR Imaging; University Hospital Essen; Essen Germany
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