Three‐frequency RF coil designed for optimized imaging of hyperpolarized, 13 C‐labeled compounds

Imaging exams involving hyperpolarized, 13 C‐labeled compounds require novel RF coils for efficient signal utilization. While 13 C coils are required for mapping the spatial distribution of the hyperpolarized compounds, imaging/pulsing at different frequencies is also needed for scan setup steps prior to the image acquisition. Imaging/pulsing at the 1 H frequency is typically used for anatomical localization and shimming. Flip angle (FA) calibration, which is difficult or impossible to achieve at the 13 C frequency, can be accurately performed at the 23 Na frequency using the natural abundance signal that exists in any living tissue. We demonstrate here a single RF resonant structure that is capable of operating linearly at the 1 H and 23 Na frequencies for scan setup steps, and in quadrature at the 13 C frequency for imaging. Images at the three resonant frequencies of this coil are presented from an exam involving hyperpolarized 13 C compounds in vivo. Magn Reson Med 60:928–933, 2008. © 2008 Wiley‐Liss, Inc.