1
|
Bhosale AA, Zhao Y, Zhang X. Electric field and SAR reduction in high-impedance RF arrays by using high permittivity materials for 7T MR imaging. PLoS One 2024; 19:e0305464. [PMID: 38959266 PMCID: PMC11221758 DOI: 10.1371/journal.pone.0305464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 05/30/2024] [Indexed: 07/05/2024] Open
Abstract
In the field of ultra-high field MR imaging, the challenges associated with higher frequencies and shorter wavelengths necessitate rigorous attention to multichannel array design. While the need for such arrays remains, and efforts to increase channel counts continue, a persistent impediment-inter-element coupling-constantly hinders development. This coupling degrades current and field distribution, introduces noise correlation between channels, and alters the frequency of array elements, affecting image quality and overall performance. The goal of optimizing ultra-high field MRI goes beyond resolving inter-element coupling and includes significant safety considerations related to the design changes required to achieve high-impedance coils. Although these coils provide excellent isolation, the higher impedance needs special design changes. However, such changes pose a significant safety risk in the form of strong electric fields across low-capacitance lumped components. This process may raise Specific Absorption Rate (SAR) values in the imaging subject, increasing power deposition and, as a result, the risk of tissue heating-related injury. To balance the requirement of inter-element decoupling with the critical need for safety, we suggest a new solution. Our method uses high-dielectric materials to efficiently reduce electric fields and SAR values in the imaging sample. This intervention tries to maintain B1 efficiency and inter-element decoupling within the existing array design, which includes high-impedance coils. Our method aims to promote the full potential of ultra-high field MRI by alleviating this critical safety concern with minimal changes to the existing array setup.
Collapse
Affiliation(s)
- Aditya A. Bhosale
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States of America
| | - Yunkun Zhao
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States of America
| | - Xiaoliang Zhang
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States of America
- Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY, United States of America
| |
Collapse
|
2
|
Heij J, Raimondo L, Siero JCW, Dumoulin SO, van der Zwaag W, Knapen T. A selection and targeting framework of cortical locations for line-scanning fMRI. Hum Brain Mapp 2023; 44:5471-5484. [PMID: 37608563 PMCID: PMC10543358 DOI: 10.1002/hbm.26459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/15/2023] [Accepted: 08/02/2023] [Indexed: 08/24/2023] Open
Abstract
Depth-resolved functional magnetic resonance imaging (fMRI) is an emerging field growing in popularity given the potential of separating signals from different computational processes in cerebral cortex. Conventional acquisition schemes suffer from low spatial and temporal resolutions. Line-scanning methods allow depth-resolved fMRI by sacrificing spatial coverage to sample blood oxygenated level-dependent (BOLD) responses at ultra-high temporal and spatial resolution. For neuroscience applications, it is critical to be able to place the line accurately to (1) sample the right neural population and (2) target that neural population with tailored stimuli or tasks. To this end, we devised a multi-session framework where a target cortical location is selected based on anatomical and functional properties. The line is then positioned according to this information in a separate second session, and we tailor the experiment to focus on the target location. Anatomically, the precision of the line placement was confirmed by projecting a nominal representation of the acquired line back onto the surface. Functional estimates of neural selectivities in the line, as quantified by a visual population-receptive field model, resembled the target selectivities well for most subjects. This functional precision was quantified in detail by estimating the distance between the visual field location of the targeted vertex and the location in visual cortex (V1) that most closely resembled the line-scanning estimates; this distance was on average ~5.5 mm. Given the dimensions of the line, differences in acquisition, session, and stimulus design, this validates that line-scanning can be used to probe local neural sensitivities across sessions. In summary, we present an accurate framework for line-scanning MRI; we believe such a framework is required to harness the full potential of line-scanning and maximize its utility. Furthermore, this approach bridges canonical fMRI experiments with electrophysiological experiments, which in turn allows novel avenues for studying human physiology non-invasively.
Collapse
Affiliation(s)
- Jurjen Heij
- Spinoza Centre for NeuroimagingAmsterdamNetherlands
- Department of Computational Cognitive Neuroscience and NeuroimagingNetherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Experimental and Applied PsychologyVU UniversityAmsterdamNetherlands
| | - Luisa Raimondo
- Spinoza Centre for NeuroimagingAmsterdamNetherlands
- Department of Computational Cognitive Neuroscience and NeuroimagingNetherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Experimental and Applied PsychologyVU UniversityAmsterdamNetherlands
| | - Jeroen C. W. Siero
- Spinoza Centre for NeuroimagingAmsterdamNetherlands
- Department of Computational Cognitive Neuroscience and NeuroimagingNetherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of RadiologyUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Serge O. Dumoulin
- Spinoza Centre for NeuroimagingAmsterdamNetherlands
- Department of Computational Cognitive Neuroscience and NeuroimagingNetherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Experimental and Applied PsychologyVU UniversityAmsterdamNetherlands
- Department of Experimental PsychologyUtrecht UniversityUtrechtNetherlands
| | - Wietske van der Zwaag
- Spinoza Centre for NeuroimagingAmsterdamNetherlands
- Department of Computational Cognitive Neuroscience and NeuroimagingNetherlands Institute for NeuroscienceAmsterdamNetherlands
| | - Tomas Knapen
- Spinoza Centre for NeuroimagingAmsterdamNetherlands
- Department of Computational Cognitive Neuroscience and NeuroimagingNetherlands Institute for NeuroscienceAmsterdamNetherlands
- Department of Experimental and Applied PsychologyVU UniversityAmsterdamNetherlands
| |
Collapse
|
3
|
Priovoulos N, de Oliveira IAF, Poser BA, Norris DG, van der Zwaag W. Combining arterial blood contrast with BOLD increases fMRI intracortical contrast. Hum Brain Mapp 2023; 44:2509-2522. [PMID: 36763562 PMCID: PMC10028680 DOI: 10.1002/hbm.26227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/20/2023] [Accepted: 01/26/2023] [Indexed: 02/11/2023] Open
Abstract
BOLD fMRI is widely applied in human neuroscience but is limited in its spatial specificity due to a cortical-depth-dependent venous bias. This reduces its localization specificity with respect to neuronal responses, a disadvantage for neuroscientific research. Here, we modified a submillimeter BOLD protocol to selectively reduce venous and tissue signal and increase cerebral blood volume weighting through a pulsed saturation scheme (dubbed Arterial Blood Contrast) at 7 T. Adding Arterial Blood Contrast on top of the existing BOLD contrast modulated the intracortical contrast. Isolating the Arterial Blood Contrast showed a response free of pial-surface bias. The results suggest that Arterial Blood Contrast can modulate the typical fMRI spatial specificity, with important applications in in-vivo neuroscience.
Collapse
Affiliation(s)
- Nikos Priovoulos
- Spinoza Center for Neuroimaging, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
- Computational Cognitive Neuroscience and Neuroimaging, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Icaro Agenor Ferreira de Oliveira
- Spinoza Center for Neuroimaging, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
- Computational Cognitive Neuroscience and Neuroimaging, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
- Experimental and Applied Psychology, VU University, Amsterdam, The Netherlands
| | - Benedikt A Poser
- MR-Methods Group, Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany
| | - Wietske van der Zwaag
- Spinoza Center for Neuroimaging, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
- Computational Cognitive Neuroscience and Neuroimaging, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| |
Collapse
|
4
|
Wolfs EML, van Lutterveld R, Varkevisser T, Klaus J, Geuze E, Schutter DJLG. Lower cerebello-cortical functional connectivity in veterans with reactive aggression symptoms: A pilot study. J Psychiatr Res 2023; 159:42-49. [PMID: 36657313 DOI: 10.1016/j.jpsychires.2023.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/05/2022] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
A significant number of veterans experience irritability and aggression symptoms as a result of being exposed to extremely stressful and life-threatening situations. In addition to the well-established involvement of the brain's cortico-subcortical circuit in aggression-related behaviours, a role of the deep cerebellar nuclei (DCN) in reactive aggression has been suggested. In the present study, seed-based resting-state functional connectivity between the DCN and cortico-subcortical areas was explored in veterans with and without reactive aggression symptoms. Nineteen male veterans with reactive aggression symptoms and twenty-two control veterans without reactive aggression symptoms underwent 3T resting-state functional MRI scans. Region-of-interest (ROI) analyses that included the amygdala, hypothalamus and periaqueductal grey as ROIs did not yield significant group-related differences in resting-state functional connectivity with the DCN. However, exploratory whole-brain analysis showed that veterans with reactive aggression symptoms exhibited lower functional connectivity between the DCN and the orbitofrontal cortex compared to control veterans. Our findings provide preliminary evidence for the possible involvement of a cerebello-prefrontal pathway in reactive aggression in male veterans.
Collapse
Affiliation(s)
- E M L Wolfs
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Heidelberglaan 1, 3584 CS, Utrecht, the Netherlands.
| | - R van Lutterveld
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands; Brain Research & Innovation Centre, Ministry of Defence, Lundlaan 1, 3584 EZ, Utrecht, the Netherlands
| | - T Varkevisser
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands; Brain Research & Innovation Centre, Ministry of Defence, Lundlaan 1, 3584 EZ, Utrecht, the Netherlands; Research and Documentation Centre, Ministry of Justice and Security, Koningskade 4, 2596 AA, The Hague, the Netherlands
| | - J Klaus
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Heidelberglaan 1, 3584 CS, Utrecht, the Netherlands
| | - E Geuze
- Department of Psychiatry, UMC Utrecht Brain Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands; Brain Research & Innovation Centre, Ministry of Defence, Lundlaan 1, 3584 EZ, Utrecht, the Netherlands
| | - D J L G Schutter
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Heidelberglaan 1, 3584 CS, Utrecht, the Netherlands
| |
Collapse
|