A Compact Planar Triple-Nuclear Coil for Small Animal 1H, 13C, and 31P Metabolic MR Imaging at 14.1 T

Multi-nuclear radio-frequency (RF) coils at ultrahigh field strengths are challenging to develop due to the high operating frequency, increased electromagnetic interaction among the coil elements, and increased electromagnetic interaction between the coils and the subject. In this work, a triple-nuclear surface coil for 1H, 13C, and 31P for small animal metabolic imaging at 14.1 T is built by nesting three surface coil geometries: a lumped-element L-C loop coil, a butterfly coil, and a microstrip transmission line (MTL) resonator. The loop coil, butterfly coil, and MTL are tuned to 31P, 13C, and 1H, respectively. The successful bench tests and phantom imaging with this novel triple-nuclear coil demonstrates the feasibility of the design for triple-nuclear MR imaging and spectroscopy studies at the ultrahigh field of 14.1 T. In particular, the microstrip transmission line resonator demonstrates excellent coil performance for proton imaging at 600 MHz, where conventional lumped-element design is limited.