Double Tuned 31P/1H Elliptical Transceiver Phased Array for the Human Brain Studies at 7 T

Introduction: The improved SNR at 7T provides significant advantages for both H and lower gyromagnetic nuclei such as P, Na and C (X nuclei). Double resonant volume head coils, based on both birdcage (1-3) and TEM (4) designs have been previously used at lower magnetic fields. However at 7T, transceiver phased arrays provide significant advantages for both B1 homogeneity and transmit efficiency over volume coils. Similarly, phased arrays for reception provide additional SNR gains for peripheral locations for studies of X nuclei. Therefore, double tuned transceiver arrays may provide substantial advantages over conventional double tuned volume head coils. However, double tuned transceiver arrays are substantially more complicated than single tuned arrays since all individual coils must be decoupled at both resonance frequencies. We have developed a 16-element (8 elements at each frequency) split elliptical P/H (120.7/298 MHz) 7T transceiver phased array. This design improved both coil’s efficiency and homogeneity.