Opencage radio frequency coil for magnetic resonance imaging

Nikulin, A. V.; Rosny, Julien de; Haliot, Kylian; Larrat, Benoît; Ourir, Abdelwaheb

doi:10.1063/1.5082245

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…Therefore, the interlayer coupling effect of planar optical metacavity (including zero-index metacavity and hyperbolic metacavity) and its novel functions will also provide ways for the design of nextgeneration optical cavity devices. In general, the metacavity can flexibly control the near field of EM wave, and it is expected to be applied in wireless power transfer [358][359][360][361][362], wireless sensing [363][364][365][366][367], magnetic resonance imaging [368][369][370][371][372][373], etc. In particular, although the current researches on ZIMs, HMMs, and the related metacavities are mainly focused on EM wave system, the related research results are expected to be well extended to acoustic [374][375][376][377] and thermal [378][379][380][381][382][383][384] systems.…”

Section: Discussionmentioning

confidence: 99%

Zero-index and hyperbolic metacavities: fundamentals and applications

Guo

Jiang

Chen

2021

J. Phys. D: Appl. Phys.

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As a basic building block, optical resonant cavities (ORCs) are widely used in light manipulation. They can confine electromagnetic waves and improve the interaction between light and matter, which also plays an important role in cavity quantum electrodynamics, nonlinear optics and quantum optics. In recent years, the rise of metamaterials, artificial materials composed of subwavelength unit cells, has greatly enriched the design and functionality of ORCs. Here, we review zero-index hyperbolic metamaterials for constructing novel ORCs. First, this paper introduces the classification and implementation of zero-index hyperbolic metamaterials. Second, the distinctive properties of zero-index and hyperbolic cavities are summarized, including geometric invariance, homogeneous/inhomogeneous field distribution, topological protection (anomalous scaling law, size independence, continuum of higher-order modes, and dispersionless modes) for zero-index (hyperbolic) metacavities. Finally, the paper introduces some typical applications of zero-index and hyperbolic metacavities, and advances the research of metacavities.

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Section: Discussionmentioning

confidence: 99%

Zero-index and hyperbolic metacavities: fundamentals and applications

Guo

Jiang

Chen

2021

J. Phys. D: Appl. Phys.

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“…A fast low-angle shot (FLASH) localizer sequence was run after wobble, iterative shimming, frequency and power adjustment. B1 + maps in coronal and sagittal orientations were obtained using the actual flip angle imaging (AFI) [15][16][17] The 1 H images were obtained using a 2D FLASH (TE / TR = 2.54 / 500 ms, α = 60°, slice thickness = 0.9 mm, in-plane spatial resolution = 0.7x0.7 mm 2 , FOV = 9x9 cm 2 ). The obtained signal was processed with MATLAB to calculate the SNR maps as the ratio of each pixel over the noise standard deviation of the image.…”

Section: Mri Experimentsmentioning

confidence: 99%

RF Coils for Preclinical Multinuclear Imaging Based on Coupled-wire Structures Working in Resonant and Non-resonant Regime

Gomez¹,

Kober²,

Dubois³

et al. 2019

2019 PhotonIcs &Amp; Electromagnetics Research Symposium - Spring (PIERS-Spring)

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Passive inductive metamaterials have been explored as alternative radio frequency (RF) coils for magnetic resonance imaging (MRI) with the aim to control and optimize the imaged volume and the sensitivity independently. Nevertheless, such structures result in a low signal-to-noise ratio (SNR) since the contribution of the loop in the global performance of the coil is reduced. Therefore, the purpose of this work is to explore a new strategy by combining off-resonance metamaterials with a resonant surface coil and observe the advantages that can be obtained. An elementary structure consisting of two parallel off-resonance wires coupled with a resonant surface coil was numerically analyzed. For experimental characterization, a prototype was built and tested in a 7 T MRI scanner for proton ( 1 H) and fluorine ( 19 F) using a phantom. In addition, other coil setups were tested for reference and comparison in terms of B1 + magnetic field homogeneity, signal and noise. The resultsshow that with this new strategy a conventional surface coil can be optimized in terms of sensitive volume while maintaining its high SNR. Metamaterials permit a customized adjustment of volume and sensitivity in addition to the simple adaptation to other nuclei, making them beneficial elements in the design of RF coils.

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“…For example, to improve the localized receive sensitivity of individual elements [20]- [24]. Transmit structures have also been developed [25], [26], but comparison to established RF resonators or ''coils'' is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Metamaterial Liner for MRI Excitation—Part 1: Theory, Modeling and Design

et al. 2022

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This work details the practical and theoretical concepts underlying the design of a metamaterial (MM) liner for magnetic resonance imaging (MRI) radio frequency (RF) excitation. The Part 2 companion to this paper details the practical design and performance comparison to a conventional birdcage coil. The operation of the MM liner relies on specifically engineered effective permittivity and permeability of a thin liner on the inner surface of the MRI bore, to enable the propagation of electromagnetic (EM) waves at frequencies below the natural-cutoff of the bore itself. Here, the effective anisotropic EM properties of the MM liner structure are calculated by a combined circuit-and effective-medium model, and the analytical dispersion characteristics are compared to full-wave eigenmode simulations. The results of the effective medium model representation of the MM liner agree fundamentally with simulation. The model may thus assist the design and tuning of the liner to achieve a standing-wave resonance with field distribution and mode spacing suitable for MRI RF excitation. The transmission properties and EM fields of a full-scale MM lined bore for B 0 = 4.7 T MRI are simulated including realistic losses. These methods enable robust design of thin MM liners for arbitrary bore sizes and B 0 field strengths.

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Opencage radio frequency coil for magnetic resonance imaging

Abstract: Wideband electromagnetic dynamic acoustic transducers (WEMDATs) for air-coupled ultrasonic applications Applied Physics Letters 114, 053505 (2019);

Cited by 11 publications

References 15 publications

Zero-index and hyperbolic metacavities: fundamentals and applications

Zero-index and hyperbolic metacavities: fundamentals and applications

RF Coils for Preclinical Multinuclear Imaging Based on Coupled-wire Structures Working in Resonant and Non-resonant Regime

Metamaterial Liner for MRI Excitation—Part 1: Theory, Modeling and Design

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