%0 Journal Article
%A Ha, YongHyun
%A Choi, Chang-Hoon
%A Worthoff, Wieland
%A Shymanskaya, Aliaksandra
%A Schöneck, Michael
%A Willuweit, Antje
%A Felder, Jörg
%A Shah, N. J.
%T Design and use of a folded four-ring double-tuned birdcage coil for rat brain sodium imaging at 9.4 T
%J Journal of magnetic resonance
%V 286
%@ 1090-7807
%C Amsterdam [u.a.]
%I Elsevier
%M FZJ-2018-00163
%P 110 - 114
%D 2018
%X A folded four-ring quadrature birdcage coil was designed and constructed with a double-tune configuration of an outer high-pass coil for 1H (400 MHz) and inner low-pass coil for 23Na (105.72 MHz at 9.4 T). The coil was evaluated on the bench and in the scanner, comparing its performance with that of single-tuned coils and a large four-ring coil. All coils were tuned and matched and the isolation between two quadrature ports was found to be better than −13.7 dB for 1H and −27 dB for 23Na. Signal-to-noise ratios (SNRs) were calculated and 23Na flip angle maps were acquired. 23Na SNR of the folded four-ring reached ∼93% of that obtained with the single-tuned coil. A set of in vivo1H and 23Na axial images to cover the whole rat brain were obtained. The performance of the folded four-ring coil and its benefit for 23Na imaging experiments have been demonstrated. This proposed four-ring coil could avoid length restrictions, e.g. the shoulders, by folding the outer rings vertically. This facilitates the construction of double-tuned four-ring birdcage coils just to fit the head, leading to higher filling factors and better SNR.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:29227914
%U <Go to ISI:>//WOS:000424071300015
%R 10.1016/j.jmr.2017.12.003
%U https://juser.fz-juelich.de/record/841866