To perform multinuclear magnetic resonance spectroscopy and imaging, a coil with a high signal-to-noise ratio and spatially uniform B1 field that covers the same volume of interest at several frequencies is preferred. A radio frequency surface coil probe that produces a homogeneous field within the same volume for both 31P and 1H is described. The probe provides signal to noise characteristics close to those of a single frequency double ring assembly. It acquired excellent proton images and 31P spectra from an image selected voxel in rat liver at 7 T. The probe uses a double ring construction where each ring is tuned by a parallel LC trap to two or more different frequencies. A calculation of the values of the inductance and capacitance allows the double coil arrangement to be tuned to the required frequencies with a peak of the homogeneity at each frequency occurring at the same distance from the coil and with good Q. The probe is powered by a driver coil adjacent to the probe by mutual inductance.
Multiple tunable double ring surface coil with high B1 homogeneity