Dedicated receiver array coil for 1H lung imaging with same‐breath acquisition of hyperpolarized 3He and 129Xe gas

Rao, Madhwesha; Robb, Fraser; Wild, Jim M.

doi:10.1002/mrm.25384

Cited by 12 publications

(16 citation statements)

References 27 publications

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“…Trap circuits are commonly used to tune the coil resonance to multiple frequencies using inductive and capacitive elements in parallel. However, for 19 F (60.06 MHz at 1.5 T) and 1 H (63.8 MHz at 1.5 T) the bandwidth of passive traps with the typical Q‐factors of commercially available components is comparable to the frequency separation, limiting their use, as discussed previously . Another approach is to actively switch‐in capacitors in parallel to the existing tuning capacitors using PIN diodes, and more recently the use of field effect transistors and micro‐electromechanical systems (MEMS) have also been reported.…”

Section: Introductionmentioning

confidence: 99%

“…However, for 19 F (60.06 MHz at 1.5 T) and 1 H (63.8 MHz at 1.5 T) the bandwidth of passive traps with the typical Q-factors of commercially available components is comparable to the frequency separation, limiting their use, as discussed previously. 5 Another approach is to actively switch-in capacitors in parallel to the existing tuning capacitors using PIN diodes, and more recently the use of field effect transistors 6 and micro-electromechanical systems (MEMS) [7][8][9] have also been reported. The equivalent series resistance (ESR) of these three devices are reported to be insignificant when compared with the quality factor (Q) of trap circuit inductors (eg.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Maunder

Rao

Robb

et al. 2018

Magnetic Resonance in Med

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PurposeTo evaluate the performance of micro‐electromechanical systems (MEMS) switches against PIN diodes for switching a dual‐tuned RF coil between 19F and 1H resonant frequencies for multi‐nuclear lung imaging.MethodsA four‐element fixed‐phase and amplitude transmit–receive RF coil was constructed to provide homogeneous excitation across the lungs, and to serve as a test system for various switching methods. The MR imaging and RF performance of the coil when switched between the 19F and 1H frequencies using MEMS switches, PIN diodes and hardwired configurations were compared.ResultsThe performance of the coil with MEMS or PIN diode switching was comparable in terms of RF measurements, transmit efficiency and image SNR on both 19F and 1H nuclei. When the coil was not switched to the resonance frequency of the respective nucleus being imaged, reductions in the transmit efficiency were observed of 32% at the 19F frequency and 12% at the 1H frequency. The coil provides transmit field homogeneity of ±12.9% at the 1H frequency and ±14.4% at the 19F frequency in phantoms representing the thorax with the air space of the lungs filled with perfluoropropane gas.ConclusionMEMS and PIN diodes were found to provide comparable performance in on‐state configuration, while MEMS were more robust in off‐state high‐powered operation (>1 kW), providing higher isolation and requiring a lower DC switching voltage than is needed for reverse biasing of PIN diodes. In addition, clear benefits of switching between the 19F and 1H resonances were demonstrated, despite the proximity of their Larmor frequencies.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Maunder

Rao

Robb

et al. 2018

Magnetic Resonance in Med

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“…The reliance on the 1 H MR system's birdcage body coil for signal reception constrains the signal-tonoise ratio (SNR) in 1 H images of the lung, which is already limited by the low proton density of lung parenchyma. In a recent study (23), we showed that the 1 H lung SNR in same-breath imaging can be improved with a nested 1 H receive array, which is compatible with operation with either a 3 He or a 129 Xe T-R coil.…”

Section: Introductionmentioning

confidence: 94%

“…Both the elements of the dual Helmholtz were fitted with two traps; one trap at the 1 H frequency to enable 1 H imaging with this coil in situ and the other trap to dual-tune the coil to the 129 Xe and 3 He Larmor frequencies. The trap design was based on the formalism established in our earlier study for multituned resonators (23), the frequency of the trap for dual-tuning was 47.81 MHz. A high-pass matching circuit was used to match the coil at both resonant frequencies of 3 He (48.62 MHz) and 129 Xe (17.65 MHz) at 1.5T.…”

Section: He and 129 Xe Dual-tuned Coil Designmentioning

confidence: 99%

“…To achieve this, we developed a new dual-tuned flexible T-R RF coil to operate in quadrature for both 3 He and 129 Xe at 1.5T. For 1 H imaging, we incorporated the 1 H array developed in our previous study designed to nest within either 3 He or 129 Xe T-R RF coils (23). With the developed RF instrumentation, we demonstrated triple nuclear same-breath lung imaging with hyperpolarized 3 He and 129 Xe ventilation images and 1 H anatomical images.…”

Section: Introductionmentioning

confidence: 99%

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RF instrumentation for same‐breath triple nuclear lung MR imaging of ¹H and hyperpolarized ³He and ¹²⁹Xe at 1.5T

Rao

Wild

2015

Magnetic Resonance in Med

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PurposeThe hyperpolarized gases 3He and 129Xe have distinct properties and provide unique and complementary functional information from the lungs. A triple‐nuclear, same‐breath imaging examination of the lungs with 1H, 3He, and 129Xe can therefore provide exclusive functional information from the gas images. In addition, the 1H images provide complementary co‐registered structural information in the same physiological time frame. The goal of this study was to design an RF system for triple nuclear lung MRI at 1.5T, consisting of a dual‐tuned transceiver coil for 3He and 129Xe, RF switches and a nested 1H receiver array.MethodsA dual‐tuned transmit‐receive dual‐Helmholtz RF coil for 3He and 129Xe was designed and constructed to work in unison with a nested 1H receiver array.ResultsTriple‐nuclear imaging (structural and ventilation) and apparent diffusion coefficient mapping of the human lungs was performed in the same breath‐hold using the integrated RF system. B1 maps and volumetric ventilation imaging using a three‐dimensional, balanced steady‐state free precession pulse sequence performed with both hyperpolarized 3He and 129Xe indicate good stand‐alone performance of the coil for the respective nucleus.ConclusionTriple‐nuclear same‐breath lung imaging with a dual‐tuned coil (3He and 129Xe) and a nested 1H array has been demonstrated with a custom RF system. Magn Reson Med 75:1841–1848, 2016. © © The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

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Multi‐ and dual‐tuned microstripline‐based transmit/receive switch for 7‐Tesla magnetic resonance imaging

Abuelhaija

Saleh

Nashwan

et al. 2021

Int J Imaging Syst Tech

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This article introduces two new designs of transmit/receive switches for 7‐Tesla magnetic resonance imaging. Both designs based on a microstripline coupler technology. In the first design, a different single frequency signals can be handled to/from a radio frequency coil using smart tuning network. In the second design, a dual‐tuned 1H/23Na transmit/receive switch is designed to handle a dual resonant signal to a dual resonant 1H/23Na coil, simultaneously and without tuning. In transmit and receive, the first design achieved good matching (‐20 dB), and low insertion loss (0.78 dB) for the 1H, 19F, 31P, 13C, and 23Na magnetic resonance signals with high isolation (61 dB). Similarly, the dual‐tuned 1H/23Na switch achieved good matching (<−11.5 dB) and low insertion loss (1.0 dB) with high isolation (67 dB), whereas for 1H/31P switch, good matching has been achieved (<−12 dB) and low insertion loss (0.96 dB) with high isolation (62 dB). The first proposed switch enables the use of the same switch with different coils resonating at Larmor frequencies of different atomic nuclei. The second switch can handle a dual resonant signal to a single dual resonant coil. The first design is promising in reducing the costs by using the same switch with different coils. The second design is promising in the integration with multichannel dual resonant coil.

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Dedicated receiver array coil for ¹H lung imaging with same‐breath acquisition of hyperpolarized ³He and ¹²⁹Xe gas

Abstract: An array coil to improve H SNR of the lung in same-breath acquisition with hyperpolarized gases has been demonstrated. Magn Reson Med 74:291-299, 2015. © 2014 Wiley Periodicals, Inc.

Cited by 12 publications

References 27 publications

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

RF instrumentation for same‐breath triple nuclear lung MR imaging of ¹H and hyperpolarized ³He and ¹²⁹Xe at 1.5T

Multi‐ and dual‐tuned microstripline‐based transmit/receive switch for 7‐Tesla magnetic resonance imaging

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Dedicated receiver array coil for 1H lung imaging with same‐breath acquisition of hyperpolarized 3He and 129Xe gas

Abstract: An array coil to improve H SNR of the lung in same-breath acquisition with hyperpolarized gases has been demonstrated. Magn Reson Med 74:291-299, 2015. © 2014 Wiley Periodicals, Inc.

Cited by 12 publications

References 27 publications

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

RF instrumentation for same‐breath triple nuclear lung MR imaging of 1H and hyperpolarized 3He and 129Xe at 1.5T

Multi‐ and dual‐tuned microstripline‐based transmit/receive switch for 7‐Tesla magnetic resonance imaging

Contact Info

Product

Resources

About

Dedicated receiver array coil for ¹H lung imaging with same‐breath acquisition of hyperpolarized ³He and ¹²⁹Xe gas

RF instrumentation for same‐breath triple nuclear lung MR imaging of ¹H and hyperpolarized ³He and ¹²⁹Xe at 1.5T