A Nested Dual Frequency Birdcage/Stripline Coil for Sodium/Proton Brain Imaging at 7T

Graham C. Wiggins¹, Ryan Brown¹, Lazar Fleysher¹, Bei Zhang¹, Bernd Stoeckel², Matilde Inglese^1,3, Daniel K. Sodickson¹

The design of a novel dual frequency coil for 7T sodium/proton brain imaging is discussed. The nested coil utilized a high-pass birdcage for sodium detection and an eight-channel stripline array for proton detection. This design showed minimal interaction between the sodium and proton coils, allowing independent tuning at both frequencies. The proton striplines partially shielded the sodium birdcage, resulting in only an 8% SNR loss compared to that of the isolated birdcage, while transmit efficiency was reduced by 20%. The proton stripline coil provided adequate sensitivity for anatomical imaging and B0 shimming.