High-Tc superconducting rf receiver coils for magnetic resonance imaging of small animals

Wosik, J.; Nesteruk, K.; Xie, Lei; Strikovski, M.; Wang, F.; Miller, John H.; Bilgen, Mehmet; Narayana, Ponnada A.

doi:10.1016/s0921-4534(00)01359-9

Cited by 15 publications

(7 citation statements)

References 9 publications

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“…There are different approaches to develop a dedicated cryostat to cool RF coils. Most cooling systems involve the direct immersion of the coil in liquid nitrogen (LN2) using for example Styrofoam vessels [10][11][12][13][14]. Some publications report the use of cold fingers made of solid materials with high thermal conductivity and low dielectric losses, such as sapphire or alumina [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Versatile cryogen-free cryostat for the electromagnetic characterization of superconducting radiofrequency coils

et al. 2020

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The use of high temperature superconducting (HTS) radio frequency (RF) coils in Magnetic Resonance Imaging (MRI) greatly improves the signal-to-noise ratio (SNR) in many biomedical applications and particularly in micro-MRI. However, a detailed understanding of the electrical behavior of HTS coils is important in order to optimize their performance through MR experiments. This paper presents a simple and versatile cryogen-free cryostat designed to characterize the RF properties of HTS coils prior to their use in MRI. The cryostat can be used at temperatures from 50 K to 300 K, with a control precision of approximately 3 mK at 70 K, and can measure the RF electrical power transmitted to an HTS coil over a range from 1 μW to 10 W. The quality factor and resonance frequency of the tested HTS coil are determined as a function of the temperature and the power it dissipates. This cryostat also permits the dynamic adjustment of the coil resonance frequency via temperature control. Finally, this study demonstrates that the HTS coil takes less than 12 μs to transit from the superconducting to the dissipative state, which is compatible with MRI requirements.

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Section: Introductionmentioning

confidence: 99%

Versatile cryogen-free cryostat for the electromagnetic characterization of superconducting radiofrequency coils

et al. 2020

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“…Improvement of signal-to-noise ratio (SNR) using HTS surface resonators has been reported in various studies performed either on humans [1], [2], [3], small animals [2], [4], [5], or in-vitro samples [6], [7]. HTS thin films and HTS tapes are usually used as receiving coils.…”

Section: Introductionmentioning

confidence: 99%

“…A 1.5-fold signal-to-noise ratio (SNR) gain for kiwi fruit imaging and a 2-fold for a rat brain, both at 77 K, were obtained, compared with images obtained using a conventional copper surface resonator at 77 K. However, most cooling systems dedicated to MRI detection involved direct immersion in a bath of liquid nitrogen (LN 2 ). LN 2 bathes were contained in styrofoam vessels [12], [13], or in non-conductive Dewar vessels made of various non-conducting materials, such as PVC [14] and fiberglass composites (G10) [15], [16], [17]. The duration of such thermal insulation is approximately 1 hour for imaging samples.…”

Section: Introductionmentioning

confidence: 99%

A Temperature-Stable Cryo-System for High-Temperature Superconducting MR In-Vivo Imaging

2013

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To perform a rat experiment using a high-temperature superconducting (HTS) surface resonator, a cryostat is essential to maintain the rat's temperature. In this work, a compact temperature-stable HTS cryo-system, keeping animal rectal temperature at 37.4°C for more than 3 hours, was successfully developed. With this HTS cryo-system, a 40-mm-diameter Bi2Sr2Ca2Cu3Ox (Bi-2223) surface resonator at 77 K was demonstrated in a 3-Tesla MRI system. The proton resonant frequency (PRF) method was employed to monitor the rat's temperature. Moreover, the capacity of MR thermometry in the HTS experiments was evaluated by correlating with data from independent fiber-optic sensor temperature measurements. The PRF thermal coefficient was derived as 0.03 rad/°C and the temperature-monitoring architecture can be implemented to upgrade the quality and safety in HTS experiments. The signal-to-noise ratio (SNR) of the HTS surface resonator at 77 K was higher than that of a professionally made copper surface resonator at 300 K, which has the same geometry, by a 3.79-fold SNR gain. Furthermore, the temperature-stable HTS cryo-system we developed can obtain stable SNR gain in every scan. A temperature-stable HTS cryo-system with an external air-blowing circulation system is demonstrated.

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“…The magnitude of noise added by the passive components increases both with their ohmic losses and with their temperature. Therefore, in addition to using good room-temperature conductors and high-quality lumped reactances, these noise contributions can also be reduced by cryogenic cooling [2][3][4][5][6] and by the use of superconductors [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Noise figure characterization of preamplifiers at NMR frequencies

Nordmeyer-Massner

Zanche

Pruessmann

2011

Journal of Magnetic Resonance

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High-Tc superconducting rf receiver coils for magnetic resonance imaging of small animals

Cited by 15 publications

References 9 publications

Versatile cryogen-free cryostat for the electromagnetic characterization of superconducting radiofrequency coils

Versatile cryogen-free cryostat for the electromagnetic characterization of superconducting radiofrequency coils

A Temperature-Stable Cryo-System for High-Temperature Superconducting MR In-Vivo Imaging

Noise figure characterization of preamplifiers at NMR frequencies

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