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Autonomous cryogenic RF receive coil for 13 C imaging of rodents at 3 T
Author(s) -
SánchezHeredia Juan Diego,
Baron Rafael,
Hansen Esben Søvsø Szocska,
Laustsen Christoffer,
Zhurbenko Vitaliy,
ArdenkjærLarsen Jan Henrik
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28113
Subject(s) - cryostat , electromagnetic coil , liquid nitrogen , radiofrequency coil , preamplifier , nuclear magnetic resonance , materials science , cryogenics , analytical chemistry (journal) , chemistry , physics , optoelectronics , superconductivity , chromatography , quantum mechanics , amplifier , organic chemistry , cmos
Purpose To develop an autonomous, in‐bore, MR‐compatible cryostat cooled with liquid nitrogen that provides full‐day operation, and to demonstrate that the theoretical signal‐to‐noise benefit can be achieved for 13 C imaging at 3 T (32.13 MHz). Methods The cryogenic setup uses a vacuum‐insulated fiberglass cryostat, which indirectly cools a cold finger where the RF coil is attached. The cryostat was evacuated before use and had a reservoir of liquid nitrogen for full‐day operation. A 30 × 40 mm 2 copper coil was mounted inside the cryostat with a 3‐mm distance to the sample. Two examples of in vivo experiments of rat brain metabolism after a hyperpolarized [1‐ 13 C]pyruvate injection are reported. Results A coil Q‐factor ratio of Q 88K /Q 290K = 550/280 was obtained, and the theoretical SNR enhancement was verified with MR measurements. We achieved a coil temperature of 88 K and a preamplifier temperature of 77 K. A 2‐fold overall SNR enhancement was achieved, compared with the best case at room temperature. The thermal performance of the coil was adequate for in vivo experiments, with an autonomy of 5 hours consuming 6 L of LN 2 , extendable to over 12 hours by LN 2 refilling. Conclusion Cryogenic surface coils can be highly beneficial for 13 C imaging, provided that the coil‐to‐sample distance remains short. An autonomous, in‐bore cryostat was developed that achieved the theoretical improvement in SNR.