Imaging capabilities of the 1H-X-nucleus metamaterial-inspired multinuclear RF-coil

In this paper, we present the initial experimental investigation of a two-coil receive/transmit design for small animals imaging at 7T MRI. The system uses a butterfly-type coil tuned to 300 MHz for scanning the ¹ H nuclei and a non-resonant loop antenna with a metamaterial-inspired resonator with the ability to tune over a wide frequency range for X-nuclei. ¹ H, ³¹ P, ²³ Na and ¹³ C, which are of particular interest in biomedical MRI, were selected as test nuclei in this work. Coil simulations show the two parts of the radiofrequency (RF) assembly to be decoupled and operating independently due to the orthogonality of the excited RF transverse magnetic fields. Simulations and phantom experimental imaging show sufficiently homogeneous transverse transmit RF fields and tuning capabilities for the pilot multiheteronuclear experiments.