TY  - JOUR
A1  - Elabyad, Ibrahim A.
A1  - Terekhov, Maxim
A1  - Lohr, David
A1  - Stefanescu, Maria R.
A1  - Baltes, Steffen
A1  - Schreiber, Laura M.
T1  - A Novel Mono-surface Antisymmetric 8Tx/16Rx Coil Array for Parallel Transmit Cardiac MRI in Pigs at 7T
JF  - Scientific Reports
N2  - A novel mono-surface antisymmetric 16-element transmit/receive (Tx/Rx) coil array was designed, simulated, constructed, and tested for cardiac magnetic resonance imaging (cMRI) in pigs at 7T. The cardiac array comprised of a mono-surface 16-loops with two central elements arranged antisymmetrically and flanked by seven elements on either side. The array was configured for parallel transmit (pTx) mode to have an eight channel transmit and 16-channel receive (8Tx/16Rx) coil array. Electromagnetic (EM) simulations, bench-top measurements, phantom, and MRI experiments with two pig cadavers (68 and 46 kg) were performed. Finally, the coil was used in pilot in-vivo measurements with a 60 kg pig. Flip angle (FA), geometry factor (g-factor), signal-to-noise ratio (SNR) maps, and high-resolution cardiac images were acquired with an in-plane resolution of 0.6 mm x 0.6 mm (in-vivo) and 0.3 mm x 0.3 mm (ex-vivo). The mean g-factor over the heart was 1.26 (R = 6). Static phase B-1(+) shimming in a pig body phantom with the optimal phase vectors makes possible to improve the B-1(+) homogeneity by factor > 2 and transmit efficiency by factor > 3 compared to zero phases (before RF shimming). Parallel imaging performed in the in-vivo measurements demonstrated well preserved diagnostic quality of the resulting images at acceleration factors up to R = 6. The described hardware design can be adapted for arrays optimized for animals and humans with a larger number of elements (32-64) while maintaining good decoupling for various MRI applications at UHF (e.g., cardiac, head, and spine).
KW  - high-field MRI
KW  - stepped impedance resonators
KW  - magnetic resoncance
KW  - transceiver array
KW  - SAR safety
KW  - design
KW  - body
KW  - element
KW  - antenna
KW  - images
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229436
VL  - 10
IS  - 1
ER  -