Simultaneous 23Na/1H Imaging with Dual Excitation and Double Tuned Birdcage Coil

Introduction The tissue concentration of sodium is sensitive to disease as an indicator of cellular and metabolic integrity [1]. Due to the low 23Na MR signal level, however, relatively long scan times are required. Furthermore, an additional 1H image in needed for an anatomic co-registration. In this context, a truly simultaneous acquisition of the 23Na and 1H signal would be helpful to reduce the scan duration and avoid misregistration between the sodium and proton image. Furthermore, dual-tuned coils eliminate the need for retuning the coils, or replacing coils during examination, which would require some sort of mechanical fixation of the subject [1]. In this study, an MR sequence with dual Nuclei excitation and simultaneous sampling on the 23Na and 1H frequency was implemented, and a dual-tuned transmit/receive coil was used to enable simultaneous 23Na/1H imaging. First in vivo examples were obtained in a human knee to demonstrate the basic feasibility of true simultaneous 1H/23Na imaging.