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Development and evaluation of a multichannel endorectal RF coil for prostate MRI at 7T in combination with an external surface array
Author(s) -
Ertürk M. Arcan,
Tian Jinfeng,
Moortele PierreFrançois,
Adriany Gregor,
Metzger Gregory J.
Publication year - 2016
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.25099
Subject(s) - imaging phantom , specific absorption rate , electromagnetic coil , magnetic resonance imaging , signal to noise ratio (imaging) , nuclear medicine , prostate , radiofrequency coil , biomedical engineering , physics , materials science , medicine , radiology , computer science , optics , antenna (radio) , cancer , telecommunications , quantum mechanics
Purpose To develop and evaluate a sterilizable multichannel endorectal coil (ERC) for use in combination with an external surface array (ESA) for high‐resolution anatomical and functional studies of the prostate at 7T. Materials and Methods A two‐loop ERC (ERC‐2L) and a microstrip‐loop ERC (ERC‐ML) were compared at 7T in terms of transmit and receive performance. The best‐performing ERC was evaluated alone and in combination with the ESA through 1) simulations on both phantom and an anatomically correct numerical human model to assessB 1 +transmit and specific absorption rate (SAR) efficiencies, and 2) phantom experiments to calculateB 1 +transmit efficiency and signal‐to‐noise ratio (SNR). Phantom studies were also performed to look at heating when using the ERC as a transmitter and for comparing the new coil against a single‐channel balloon‐type ERC (ERC‐b). High‐resolution magnetic resonance imaging (MRI) acquisitions were performed on a single healthy subject using the two‐channel ERC combined with the ESA. Results Compared to the ERC‐ML, the ERC‐2L demonstrated 20% higher SAR efficiency and higher SNR 3 cm from the coil. The presence of a tuned and detuned ERC‐2L did not alter the peak local SAR of the ESA alone; however, the detuned ERC‐2L had 45% less peak local SAR around the rectum compared to the tuned ERC‐2L. The receive‐only version of the ERC‐2L improved the SNR 4.7‐fold and 1.3‐fold compared to the ESA and ERC‐b, respectively. In combination with the ESA, the ERC‐2L supported in‐plane voxel‐size of 0.36 × 0.36 mm 2 in T 2 ‐weighted anatomic imaging. Conclusion The reusable ERC‐2L combined with an ESA offers a high SNR imaging platform for translational studies of the prostate at 7T. J. Magn. Reson. Imaging 2016;43:1279–1287.