Ultra-High Field Neuro MRI

1st Edition, Volume 10 - August 21, 2023
Editors: Karin Markenroth Bloch, Maxime Guye, Benedikt A. Poser
Language: English
Paperback ISBN:
9 7 8 - 0 - 3 2 3 - 9 9 8 9 8 - 7
eBook ISBN:
9 7 8 - 0 - 3 2 3 - 9 9 9 5 3 - 3

Ultra-High Field Neuro MRI is a comprehensive reference and educational resource on the current state of neuroimaging at ultra-high field (UHF), with an emphasis on 7T. Sections… Read more

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Ultra-High Field Neuro MRI is a comprehensive reference and educational resource on the current state of neuroimaging at ultra-high field (UHF), with an emphasis on 7T. Sections cover the MR physics aspects of UHF, including the technical challenges and practical solutions that have enabled the rapid growth of 7T MRI. Individual chapters are dedicated to the different techniques that most strongly benefit from UHF, as well as chapters with a focus on different application areas in anatomical, functional and metabolic imaging. Finally, several chapters highlight the neurological and psychiatric applications for which 7T has shown benefits. The book is aimed at scientists who develop MR technologies and support clinical and neuroscience research, as well as users who want to benefit from UHF neuro MR techniques in their work. It also provides a comprehensive introduction to the field.

Cover image
Title page
Table of Contents
Series Page
Copyright
List of contributors
Editor's biographies
Foreword
Part 1: Benefits of ultra-high field
Chapter 1: The way back and ahead: MR physics at ultra-high field
Abstract
1.1: Ultra-high field in the light of the history of magnetism
1.2: SNR gain at ultra-high field
1.3: Relaxation time and contrast changes at ultra-high field
1.4: Susceptibility
1.5: Spectral resolution
1.6: RF at ultra-high field
1.7: Conclusion
References
Chapter 2: Translating UHF advances to lower field strength
Abstract
2.1: Introduction
2.2: Multicoil approaches for B0 shimming
2.3: Corrections for motion, B0-field modulation, and gradient imperfections
2.4: Development of new materials to tailor the electromagnetic field distribution in vivo
2.5: Parallel transmit technology
2.6: Clinical applications
2.7: Discussion
References
Part 2: Acquisition at ultra-high field: Practical considerations
Chapter 3: Practical solutions to practical constraints: Making things work at ultra-high field
Abstract
3.1: Introduction
3.2: Translation of workflows to 7T
3.3: Researcher acceptance of higher field
3.4: Peripheral equipment
3.5: Tailoring the study to the individual
3.6: Conclusions
References
Chapter 4: Practical considerations on ultra-high field safety
Abstract
4.1: Introduction
4.2: System overview
4.3: RF coil safety
4.4: Dielectric pads
4.5: Parallel transmission
4.6: Implant safety
4.7: Implants and parallel transmission
4.8: Conclusion
References
Chapter 5: Biological effects, patient experience, and occupational safety
Abstract
5.1: Biological effects
5.2: Static magnetic field
5.3: The time-varying gradient magnetic field
5.4: Radio-frequency (RF) fields
5.5: Patient care at UHF
5.6: Occupational safety
5.7: Practical guide to avoid or minimize biological effects, to facilitate patient comfort, and increase MR safety at UHF MR
References
Part 3: Ultra-high field challenges and technical solutions
Chapter 6: B0 inhomogeneity: Causes and coping strategies
Abstract
6.1: Scope of this chapter
6.2: Origins of ΔB0 inhomogeneity and implications for UHF MR
6.3: Measuring ΔB0
6.4: Reducing image artifacts without adjusting fields
6.5: Shim devices for controlling magnetic field in vivo
6.6: Simulated and experimental B0 shimming results for different hardware setups
6.7: Optimizing shim coil wire patterns to target brain anatomy
6.8: Shim system performance evaluation
6.9: Emerging applications
Acknowledgments
References
Chapter 7: Parallel transmission: Physics background, pulse design, and applications in neuro MRI at ultra-high field
Abstract
7.1: Introduction
7.2: B1+ inhomogeneity
7.3: Parallel transmission
7.4: Neuroimaging applications of pTx
7.5: Perspectives and conclusion
References
Chapter 8: RF coils for ultra-high field neuroimaging
Abstract
8.1: Introduction
8.2: Behavior of transmit/receive at ultra-high field
8.3: Nonstandard head coils and applications
8.4: Multituned and non-H-coils
8.5: Coil safety considerations
8.6: Outlook
8.7: Summary
References
Chapter 9: Parallel imaging and reconstruction techniques
Abstract
9.1: Introduction
9.2: Undersampled acquisitions and fundamental parallel imaging approaches
9.3: Controlled aliasing in parallel imaging (CAIPI) and non-Cartesian trajectories
9.4: Model-based reconstruction for parallel imaging
9.5: Estimation of coil sensitivities
9.6: Coil sensitivity profiles vary more rapidly across space at UHF, thereby improving g-factor performance
9.7: Exemplar applications enabled by the increased encoding power of UHF systems
Acknowledgments
References
Chapter 10: Motion correction
Abstract
10.1: Introduction
10.2: Prospective or retrospective motion correction?
10.3: Motion-tracking systems
10.4: Motion tracking: MR-based tracking
10.5: Self-navigating sequences
10.6: Motion tracking: Data-driven approaches
10.7: Conclusion
References
Part 4: Ultra-high field structural imaging: Techniques for neuroanatomy
Chapter 11: High-resolution T1-, T2-, and T2*-weighted anatomical imaging
Abstract
11.1: Introduction
11.2: Field dependence of relaxation times
11.3: Commonly used sequence types for UHF structural imaging
11.4: Conclusion
Acknowledgments
Disclosure
References
Chapter 12: Brain segmentation at ultra-high field: Challenges, opportunities, and unmet needs
Abstract
12.1: Introduction
12.2: Differentiating tissues at UHF
12.3: Intensity, contrast, and geometric biases in UHF MRI
12.4: Higher imaging resolutions
12.5: Region-specific segmentation
12.6: Direct segmentation of EPI data
12.7: Machine learning-based segmentation
12.8: Conclusions and outlook
Acknowledgments
References
Chapter 13: Phase imaging: Susceptibility-Weighted Imaging and Quantitative Susceptibility Mapping
Abstract
13.1: Introduction
13.2: The physics of magnetic susceptibility and phase
13.3: Acquisition methods
13.4: Phase processing
13.5: Susceptibility-Weighted Imaging
13.6: Quantitative Susceptibility Mapping
13.7: Clinical applications and outlook
References
Chapter 14: Quantitative MRI and multiparameter mapping
Abstract
14.1: Quantitative MRI at UHF
14.2: Quantitative MRI parameters of the brain at UHF
14.3: Methods for mapping quantitative spin parameters at UHF
14.4: Measurement of quantitative MRI parameters
14.5: Translating qMRI maps to maps of tissue composition
14.6: Neuroscience application of qMRI at UHF
14.7: Outlook and conclusions
References
Part 5: Ultra-high field structural imaging: Zooming in on the brain
Chapter 15: Cerebellar imaging at ultra-high magnetic fields
Abstract
15.1: Functional and structural cerebellar organization
15.2: Benefits, challenges, and optimization of cerebellar imaging at UHF
15.3: MRI sequences for cerebellar imaging
15.4: Processing
15.5: Imaging cerebellar morphology
15.6: Clinical applications
References
Chapter 16: Ultra-high field imaging of the human medial temporal lobe
Abstract
16.1: Introduction
16.2: Ultra-high field structural imaging of the MTL
16.3: Ultra-high field functional imaging of the MTL
16.4: Challenges of structural and functional UHF imaging
16.5: An outlook on future developments
References
Chapter 17: Imaging of subcortical deep brain structures with 7T MRI
Abstract
17.1: Introduction
17.2: Direct visualization of deep subcortical structures
17.3: Generating subject-specific segmentations of deep subcortical structures
17.4: Harnessing 7T MRI benefits to develop machine learning algorithms
17.5: Tractography and parcellation
17.6: Clinical application of 7T: Deep brain stimulation
17.7: Future directions
17.8: Conclusions
References
Chapter 18: Brainstem imaging
Abstract
18.1: Introduction
18.2: Contrast for brainstem visualization
18.3: Signal dropout and distortion
18.4: Physiological factors affecting brainstem imaging
18.5: UHF brainstem imaging applications
18.6: Best practices summary
Acknowledgments
References
Chapter 19: Ultra-high field spinal cord MRI
Abstract
19.1: Introduction
19.2: 7T spinal cord MRI: What has been achieved so far, challenges, and limitations
19.3: Clinical research applications
19.4: What's next? Perspectives, wishes, and dreams
19.5: Conclusion
References
Part 6: Diffusion and perfusion imaging at ultra-high field
Chapter 20: Diffusion MRI at ultra-high field strengths
Abstract
20.1: Introduction
20.2: Diffusion MRI and SNR
20.3: Conclusions and outlook
References
Chapter 21: Ultra-high field brain perfusion MRI
Abstract
21.1: Introduction
21.2: Potentials and challenges for ASL at UHF
21.3: Contrast-enhanced MRI at ultra-high field: Challenges and solutions
21.4: Summary
Acknowledgments
References
Part 7: Ultra-high field functional imaging
Chapter 22: BOLD fMRI: Physiology and acquisition strategies
Abstract
22.1: BOLD physiology and biophysical models
22.2: BOLD contrast contributions
22.3: BOLD sensitivity and specificity at UHF
22.4: Common acquisition sequences
22.5: Specialized acquisition sequences
22.6: Code and data availability
Acknowledgments
References
Chapter 23: Sequences and contrasts for non-BOLD fMRI
Abstract
23.1: Introduction
23.2: Motivation for using non-BOLD fMRI
23.3: Functional CBV
23.4: Functional CBF
23.5: Functional CMRO2
23.6: Discussion
Acknowledgment
References
Chapter 24: Laminar and columnar imaging at UHF: Considerations for mesoscopic-scale imaging with fMRI
Abstract
24.1: Introduction
24.2: Layers and “columns”: A brief historical overview
24.3: fMRI
24.4: Challenges of mesoscale imaging
24.5: Applications of high-resolution fMRI in cognitive neuroscience
24.6: Conclusion
Acknowledgments
References
Further reading
Chapter 25: The power of ultra-high field for cognitive neuroscience: Gray-matter optimized fMRI
Abstract
25.1: Introduction
25.2: What is the optimal spatial resolution from a cognitive neuroscience perspective?
25.3: Moving toward individualized cognitive neuroscience
25.4: Respecting local neural populations: Human systems neuroscience at UHF
25.5: Outlook
References
Part 8: Techniques for ultra-high field metabolic imaging and spectroscopy
Chapter 26: MR spectroscopy and spectroscopic imaging
Abstract
26.1: Introduction
26.2: Single voxel 1H MRS and 1H MRSI
26.3: Single-voxel 31P MRS and 31P MRSI
26.4: Single-voxel 2H MRS and 2H MRSI
26.5: Single-voxel 13C MRS and 13C MRSI
26.6: Conclusions and outlook
References
Chapter 27: Imaging with X-nuclei
Abstract
27.1: Introduction
27.2: Physics and technical aspects of X-nuclei MRI
27.3: Acquisition techniques for X-nuclei MRI
27.4: Brain biomedical applications
27.5: Conclusion
References
Chapter 28: Chemical exchange saturation transfer MRI in the human brain at ultra-high fields
Abstract
28.1: The CEST experiment and imaging sequence
28.2: Understanding the CEST signal by equations
28.3: Field inhomogeneities and limitations
28.4: Unique UHF CEST effects and applications
References
Part 9: Benefits of ultra-high field in clinical applications
Chapter 29: Epilepsy
Abstract
29.1: Background and clinical relevance
29.2: State-of-the-art imaging of patients with epilepsy
29.3: Relevance for neurosurgery
29.4: 7T state-of-the-art neuroimaging
29.5: Advanced epilepsy imaging at 7T
29.6: Summary and conclusions: UHF MRI—Why do we want it?
References
Chapter 30: Multiple sclerosis
Abstract
30.1: Introduction
30.2: Increased lesion detection
30.3: Improved lesion characterization
30.4: The damage beyond visible focal lesions
30.5: Clinical implications
30.6: Technical limitations
30.7: Future directions
References
Chapter 31: Neurovascular disease
Abstract
31.1: Introduction
31.2: Intracranial atherosclerosis
31.3: Intracranial aneurysm
31.4: Cerebral small vessel disease
31.5: Prospects
31.6: Conclusion
References
Chapter 32: Motor neuron diseases and frontotemporal dementia
Abstract
32.1: Introduction
32.2: The role of magnetic resonance imaging at 7T in the search for biomarkers of upper motor neuron impairment
32.3: Magnetic resonance imaging at 7T to investigate the topography of motor system involvement
32.4: Magnetic resonance imaging at 7T in the quest for biomarkers of frontotemporal dementia in amyotrophic lateral sclerosis
32.5: Genetic findings
32.6: Conclusions
References
Chapter 33: Parkinson's disease and atypical parkinsonism
Abstract
33.1: Substantia nigra imaging
33.2: Other deep brain nuclei
33.3: Magnetic resonance spectroscopy
33.4: Application in atypical parkinsonism
33.5: Conclusion and future directions
Acknowledgments
References
Chapter 34: Healthy aging and Alzheimer's disease
Abstract
34.1: Introduction
34.2: Assessment of cortical and subcortical neurodegeneration in AD
34.3: Toward understanding the role of vascular dysfunction in aging and AD
34.4: Iron mapping in aging and AD
34.5: Determining potential of UHF fMRI in aging and AD
34.6: The road ahead for UHF imaging in aging and AD
34.7: Conclusion
References
Chapter 35: Ultra-high field neuro-MRI: Oncological applications
Abstract
35.1: Proton MRI/MRS at ultra-high fields (UHF)
35.2: X-nuclei imaging
35.3: Outlook: Future of oncological neuroimaging at UHF
References
Chapter 36: Psychiatric applications of ultra-high field MR neuroimaging
Abstract
36.1: Introduction
36.2: Psychiatric applications of UHF MRS
36.3: Psychiatric applications of UHF structural MRI
36.4: Psychiatric applications of UHF functional MRI
36.5: Future of psychiatric UHF imaging
Acknowledgments
References
Part 10: New horizons
Chapter 37: New horizons: Human MRI at extremely high field strengths
Abstract
37.1: Introduction
37.2: Magnet design
37.3: Safety considerations
37.4: Radiofrequency fields and coil requirements
37.5: Anatomical neuroimaging
37.6: Functional neuroimaging
37.7: Metabolic and physiological imaging
37.8: Human MRI systems >11.7T
References
Index

Karin Markenroth Bloch

Karin Markenroth Bloch leads the Swedish National 7T facility at Lund University. She obtained a PhD in Nuclear Physics from Chalmers University of Technology, after which she started her career in MRI at DRCMR, Copenhagen, at one of the first Nordic 3T scanners in clinical use. These early experiences stimulated her interest in leveraging the potential of high field strength in clinical applications as much as research and neuroscience. Following a career in Philips as a clinical scientist, Dr. Markenroth Bloch returned to academia to start up and, since 2016, head the Swedish National 7T facility. In this role, her ambition is to make 7T MR broadly accessible to users in a range of applications. Her personal research interests are in methods for velocity-encoded phase-contrast MRI, and their use in studying flow of blood and CSF in the brain. Dr. Markenroth Bloch is engaged in several international and local MRI communities, and in public outreach and popular science initiatives. She has been involved in the ISMRM in a range of capacities, including as a member of the Board of Trustees, the ISMRM High Field Study Group committee and the ISMRM and ESMRMB program committees.

Affiliations and expertise

Swedish National 7T facility, Lund University, Sweden

Maxime Guye

Maxime Guye, M.D., Ph.D., is a Neurologist, Professor of Biophysics at the School of Medicine, Aix-Marseille University (AMU), and in the Medical Imaging Department of the Marseille University Hospital. He is also senior consultant in the Department of Clinical Neuroscience. He is deputy director and head of the clinical site of the Centre for Magnetic Resonance in Biology and Medicine (CRMBM), jointly operated by AMU, the French National Centre for Scientific Research (CNRS) and the University Hospital System. After a fellowship in the UCL Epilepsy Imaging Group (London, UK), he started a research activity on epilepsy imaging using multimodal MRI and electrophysiology in Marseille in 2002. Since 2014 he is leading the 7T MRI facility in Marseille and is particularly involved in clinical research and applications of 7T MRI in neurological diseases. He is actively involved in the MRI community at national and international level. He was elected to the ISMRM High Field Study Group committee and was a member of the ISMRM program committee. He has been elected President of the French Society for Magnetic Resonance in Biology & Medicine and a member of the scientific committee of the French Society of Radiology.

Affiliations and expertise

Deputy Director, Centre for Magnetic Resonance in Biology and Medicine (CRMBM), Aix-Marseille University (AMU); Director of the medical site, CRMBM, University Hospital in Marseille, France

Benedikt A. Poser

Benedikt Poser is Professor of MR Methods for Neuroscience at Maastricht University. He has a background in Physics and Business Management, and obtained a PhD in MR Physics at Radboud University Nijmegen in 2009. He gained early experience with Ultra-High Field MRI and its adaption for functional imaging at the Erwin L Hahn Institute in Essen, on one of the first human 7T systems in Europe. Following a fellowship at the University of Hawaii, he returned to Europe in 2013 for a faculty appointment at Maastricht University, where he leads the MR Methods group, and since 2020 holds a Chair within the Cognitive Neuroscience department. The central focus of his work has been the development of acquisition strategies for functional and structural MRI at UHF, and bringing parallel-transmit technologies to neuroscientific application at 7T and 9.4T. Benedikt Poser is an active member of the MRI community, with engagement in several roles in the European and International societies. Amongst other functions, he served on the ISMRM and ESMRMB program committees, and as President of the ESMRMB. Together with the co-editors of this book he also enjoyed a fruitful and rewarding time on the ISMRM High Field Study Group committee.

Affiliations and expertise

Professor of MR Methods in Neuroscience, Maastricht University, The Netherlands

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Ultra-High Field Neuro MRI

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Karin Markenroth Bloch

Maxime Guye

Benedikt A. Poser