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Construction and evaluation of a switch‐tuned 13 C ‐ 1 H birdcage radiofrequency coil for imaging the metabolism of hyperpolarized 13 C‐enriched compounds
Author(s) -
Lim Heeseung,
Thind Kundan,
MartinezSantiesteban Francisco M.,
Scholl Timothy James
Publication year - 2014
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.24458
Subject(s) - electromagnetic coil , radiofrequency coil , nuclear magnetic resonance , physics , radio frequency , diode , materials science , optics , optoelectronics , telecommunications , computer science , quantum mechanics
Purpose To construct a switch‐tuned 13 C ‐ 1 H birdcage radiofrequency (RF) coil system capable of metabolic imaging of hyperpolarized 13 C‐enriched metabolic probes for co‐registration with MRI morphology using protons. Materials and Methods The switch‐tuned coil was constructed using PIN diodes for rapid switching of the resonant frequency of the coil. Identical, single‐tuned, 1 H and 13 C birdcage RF coils have also been constructed for comparison of imaging performance. A 13 C receive‐only surface RF coil has been integrated with the switch‐tuned coil for transmit‐only, receive‐only operation (TORO) to increase local 13 C signal for improved signal‐to‐noise ratio (SNR). Results The SNR achieved with the switch‐tuned coil in transmit/receive mode was 87% that of the single‐tuned 1 H coil. For 13 C imaging, the SNR for the switch‐tuned coil was 55% that of the single‐tuned 13 C coil. TORO operation of the switch‐tuned coil with the surface coil increased SNR for by a factor of 4.2 over transmit/receive operation of the switch‐tuned coil alone. Conclusion A surface coil can be integrated with a switch‐tuned 13 C ‐ 1 H coil for 13 C TORO operation producing improved SNR. In vivo metabolic imaging of [1‐ 13 C]pyruvate in a rat model of glioma is demonstrated using TORO operation, which is co‐registered with 1 H‐imaged anatomy. J. Magn. Reson. Imaging 2014;40:1082–1090 . © 2014 Wiley Periodicals, Inc.