Double-crossed radiofrequency coil with improved uniformity for rodent MRI at 7 T

A transceiver volume coil for High Field Magnetic Resonance Imaging was developed based on Temnikov’s NMR probe coil. The critical advantage of this design is that requires only one trimmer capacitor for both tuning and matching. Electromagnetic simulations of our coil were compared to a four-rung birdcage coil to evaluate their performances. A transceiver coil prototype, called the double-cross coil and a birdcage coil were built to compare and contrast their feasibility. Both coil prototypes were operated in the linear mode. Experimental quality factors were $Q_u/Q_l=101/45$ for the double-cross coil and $Q_u/Q_l=105/43$ for the birdcage coil. Phantom images were acquired to test the viability of each coil for high field magnetic resonance imaging applications. The signal-to-noise ratios, noise factors and uniformity values were also calculated: $85.26/0.74/44.48$ for the double-cross coil and $76.54/1.9/65.65$ for the birdcage coil. These volume coils showed similar performance, but the double-cross coil has better uniformity and a slightly lower noise figure than the birdcage coil. A remarkable agreement of experimental and simulated $B_1$ was obtained for the double-cross coil. These experimental and numerical results demonstrate the feasibility of the double-cross volume coil with better uniformity for rodent magnetic resonance imaging at 7 T.