Use of mutually inductive coupling in probe design

Hoult, D. I.; Tomanek, Bogusław

doi:10.1002/cmr.10047

Cited by 71 publications

(55 citation statements)

References 48 publications

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“…Inductive coupling has been introduced and used very early in NMR and MRI (30)(31)(32)(33)(34)(35). Resonant inductive coupling to a resonator has been introduced by Diodato et al (36) in the context of EPR.…”

Section: Coupling To Rotating Coils By Resonant Inductive Couplingmentioning

confidence: 99%

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NMR signal detection using inductive coupling: Applications to rotating microcoils

Jacquinot

Sakellariou

2011

Concepts Magnetic Resonance

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Sensitivity in solid-state nuclear magnetic resonance can be improved by the use of rotating microcoils (1). The connection to the rest of the electronics is performed through resonant inductive coupling. This mode of detection of nuclear induction has major advantages as it provides a wireless way to obtain extremely high radio-frequency amplitudes per unit current under sample rotation and thus improved sensitivity for size-limited samples. We review the circuit electronics and discuss experimental optimization of the probe and coil parameters. We also present alternative geometries for coupling between rotating coils and we explicitly calculate the signal enhancement. Two practical cases are presented, namely a standard magic angle sample spinning probe and a double sample rotation probe. We conclude with a theoretical discussion about the limits of detection attainable with coil miniaturization.

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Section: Coupling To Rotating Coils By Resonant Inductive Couplingmentioning

confidence: 99%

“…[35] According to Eq. [2] the detected signal is proportional to the (complex) magnetization multiplied by the complex conjugate of the rf field:…”

Section: 7mentioning

confidence: 99%

NMR signal detection using inductive coupling: Applications to rotating microcoils

Jacquinot

Sakellariou

2011

Concepts Magnetic Resonance

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“…e.g. (17,18)] to a nonoptimal value and thus lowers the Signal-to-noise ratio (SNR) of the detected signal. This effect becomes more pronounced as M increases.…”

Section: Theorymentioning

confidence: 99%

Optically detunable, inductively coupled coil for self‐gating in small animal magnetic resonance imaging

Korn

Umathum

Schulz

et al. 2010

Magnetic Resonance in Med

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An inductively coupled coil concept is presented, which improves the compensation of physiological motion by the self-gating (SG) technique. The animal is positioned in a conventional volume coil encompassing the whole animal. A small, resonant surface coil (SG-coil) is placed on the thorax so that its sensitive region includes the heart. Via inductive coupling the SG-coil amplifies selectively the MR signal of the beating heart. With an optical detuning mechanism, this coupling can be switched off during acquisition of the MR image information, whereas it is active during SG data sampling to provide the physiological information. In vivo experiments on a mouse show an amplification of the SG signal by at least 40%. Magn Reson Med 65:882-888,

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“…6 It has also been shown in an earlier paper from our group that depth sensitivity can be reduced (tailored) using a coil structure for MRI that consisted of two loops coupled by strong mutual inductance in anti-parallel mode. 7 Use of inductive coupling in MRI has shown some advantages; [8][9][10] however, the configurations used (single-turn loops, 90…”

Section: Figmentioning

confidence: 99%

MRI surface-coil pair with strong inductive coupling

Mett

Sidabras

Hyde

2016

Review of Scientific Instruments

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A novel inductively coupled coil pair was used to obtain magnetic resonance phantom images. Rationale for using such a structure is described in R. R. Mett et al. [Rev. Sci. Instrum. 87, 084703 (2016)]. The original rationale was to increase the Q-value of a small diameter surface coil in order to achieve dominant loading by the sample. A significant improvement in the vector reception field (VRF) is also seen. The coil assembly consists of a 3-turn 10 mm tall meta-metallic self-resonant spiral (SRS) of inner diameter 10.4 mm and outer diameter 15.1 mm and a single-loop equalization coil of 25 mm diameter and 2 mm tall. The low-frequency parallel mode was used in which the rf currents on each coil produce magnetic fields that add constructively. The SRS coil assembly was fabricated and data were collected using a tissue-equivalent 30% polyacrylamide phantom. The large inductive coupling of the coils produces phase-coherency of the rf currents and magnetic fields. Finite-element simulations indicate that the VRF of the coil pair is about 4.4 times larger than for a single-loop coil of 15 mm diameter. The mutual coupling between coils influences the current ratio between the coils, which in turn influences the VRF and the signal-to-noise ratio (SNR). Data on a tissue-equivalent phantom at 9.4 T show a total SNR increase of 8.8 over the 15 mm loop averaged over a 25 mm depth and diameter. The experimental results are shown to be consistent with the magnetic resonance theory of the emf induced by spins in a coil, the theory of inductively coupled resonant circuits, and the superposition principle. The methods are general for magnetic resonance and other types of signal detection and can be used over a wide range of operating frequencies. Published by AIP Publishing. [http://dx

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Use of mutually inductive coupling in probe design

Cited by 71 publications

References 48 publications

NMR signal detection using inductive coupling: Applications to rotating microcoils

NMR signal detection using inductive coupling: Applications to rotating microcoils

Optically detunable, inductively coupled coil for self‐gating in small animal magnetic resonance imaging

MRI surface-coil pair with strong inductive coupling

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