A patient-friendly 16-channel transmit/64-channel receive coil array for combined head–neck MRI at 7 Tesla
Markus W. May, Sam-Luca J. D. Hansen, Mirsad Mahmutovic, Alina Scholz, Nicolas Kutscha, Bastien Guerin, Jason P. Stockmann, Robert L. Barry, Ehsan Kazemivalipour, Rene Gumbrecht, Ralph Kimmlingen, Markus Adriany, Yulin Chang, Christina Triantafyllou, Susanne Knake, Lawrence L. Wald, Boris Keil
Abstract
Purpose
To extend the coverage of brain coil arrays to the neck and cervical–spine region to enable combined head and neck imaging at 7 Tesla (T) ultra-high field MRI.
Methods
The coil array structures of a 64-channel receive coil and a 16-channel transmit coil were merged into one anatomically shaped close-fitting housing. Transmit characteristics were evaluated in a B 1±field mapping study and an electromagnetic model. Receive SNR and the encoding capability for accelerated imaging were evaluated and compared with a commercially available 7 T brain array coil. The performance of the head–neck array coil was demonstrated in human volunteers using high-resolution accelerated imaging.
Results
In the brain, the SNR matches the commercially available 32-channel brain array and showed improvements in accelerated imaging capabilities. More importantly, the constructed coil array improved the SNR in the face area, neck area, and cervical spine by a factor of 1.5, 3.4, and 5.2, respectively, in regions not covered by 32-channel brain arrays at 7 T. The interelement coupling of the 16-channel transmit coil ranged from −14 to −44 dB (mean = −19 dB, adjacent elements <−18 dB). The parallel 16-channel transmit coil greatly facilitates B 1+ field shaping required for large FOV neuroimaging at 7 T.
Conclusion
This new head–neck array coil is the first demonstration of a device of this nature used for combined full-brain, head–neck, and cervical-spine imaging at 7 T. The array coil is well suited to provide large FOV images, which potentially improves ultrahigh field neuroimaging applications for clinical settings.