Dual-Tuned Coaxial-Transmission-Line RF Coils for Hyperpolarized <sup>13</sup>C and Deuterium <sup>2</sup>H Metabolic MRS Imaging at Ultrahigh Fields

Payne, Komlan; Zhao, Yunkun; Bhosale, Aditya Ashok; Zhang, Xiaoliang

doi:10.1109/tbme.2023.3341760

Cited by 4 publications

(2 citation statements)

References 73 publications

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“…Traditional high-field MRI systems, typically operating at 1.5 Tesla or higher, are prevalent in clinical settings due to their high signal-to-noise ratio (SNR), which contributes to their ability to produce high-resolution images and increased spectral dispersion [24][25][26][27][28][29][30][31][32][33][34][35][36][37]. However, MRI systems operating at higher field strengths are often associated with high operating costs [38,39], substantial power requirements [40][41][42][43][44], radio frequency (RF) challenges [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] and potential safety concerns, especially for patients with certain medical implants or conditions that contraindicate exposure to strong magnetic fields [62,63]. In recent years, there has been a growing interest in low-field MRI systems, defined as those operating at magnetic field strengths in the range from 0.25 Tesla to 1.0 Tesla [64][65][66].…”

Section: Introductionmentioning

confidence: 99%

Multimodal surface coils for low field MR imaging

Zhao,

Bhosale,

Zhang

2024

Preprint

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Low field MRI is safer and more cost effective than the high field MRI. One of the inherent problems of low field MRI is its low signal-to-noise ratio or sensitivity. In this work, we introduce a multimodal surface coil technique for signal excitation and reception to improve the RF magnetic field (B1) efficiency and potentially improve MR sensitivity. The proposed multimodal surface coil consists of multiple identical resonators that are electromagnetically coupled to form a multimodal resonator. The field distribution of its lowest frequency mode is suitable for MR imaging applications. The prototype multimodal surface coils are built, and the performance is investigated and validated through numerical simulation, standard RF measurements and tests, and comparison with the conventional surface coil at low fields. Our results show that the B1 efficiency of the multimodal surface coil outperforms that of the conventional surface coil which is known to offer the highest B1 efficiency among all coil categories, i.e., volume coil, half-volume coil and surface coil. In addition, in low-field MRI, the required low-frequency coils often use large value capacitance to achieve the low resonant frequency which makes frequency tuning difficult. The proposed multimodal surface coil can be conveniently tuned to the required low frequency for low-field MRI with significantly reduced capacitance value, demonstrating excellent low-frequency operation capability over the conventional surface coil.

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Section: Introductionmentioning

confidence: 99%

Multimodal surface coils for low field MR imaging

Zhao,

Bhosale,

Zhang

2024

Preprint

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“…All of the aforementioned approaches provide excellent inter-element isolation, which improves imaging performance but also increases the complexity of array designs due to the added decoupling circuitry. The high-impedance coil design is another decoupling solution that has been revisited and further investigated recently [ 18 , 28 – 33 ]. This method not only improves inter-element isolation but also simplifies array construction by eliminating the need for additional circuitry, leading to a robust array design method with high efficiency and durability, particularly for flexible multichannel arrays.…”

Section: Introductionmentioning

confidence: 99%

Electric field and SAR reduction in high-impedance RF arrays by using high permittivity materials for 7T MR imaging

Bhosale,

Zhao,

Zhang

2024

PLoS ONE

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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.

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Multimodal surface coils for low field MR imaging

Zhao,

Bhosale,

Zhang

2024

Magnetic Resonance Imaging

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Dual-Tuned Coaxial-Transmission-Line RF Coils for Hyperpolarized ¹³C and Deuterium ²H Metabolic MRS Imaging at Ultrahigh Fields

Cited by 4 publications

References 73 publications

Multimodal surface coils for low field MR imaging

Multimodal surface coils for low field MR imaging

Electric field and SAR reduction in high-impedance RF arrays by using high permittivity materials for 7T MR imaging

Multimodal surface coils for low field MR imaging

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Dual-Tuned Coaxial-Transmission-Line RF Coils for Hyperpolarized 13C and Deuterium 2H Metabolic MRS Imaging at Ultrahigh Fields

Cited by 4 publications

References 73 publications

Multimodal surface coils for low field MR imaging

Multimodal surface coils for low field MR imaging

Electric field and SAR reduction in high-impedance RF arrays by using high permittivity materials for 7T MR imaging

Multimodal surface coils for low field MR imaging

Contact Info

Product

Resources

About

Dual-Tuned Coaxial-Transmission-Line RF Coils for Hyperpolarized ¹³C and Deuterium ²H Metabolic MRS Imaging at Ultrahigh Fields