A dual resonator system for whole-body sodium-MRI at 3T

23Na-MRI (Na-MRI) can provide unique and direct information about the tissue viability after stroke [1], and the integrity of tumor tissue [2]. Nevertheless, clinical routine use of Na-MRI techniques is mostly hindered by the required specialized resonator systems. Especially the lack of available homogeneous B1-field excitation at the 23Na frequency limits the day to day use of these novel techniques. The helmholtz design has been normally used to homogenize the 23Na B1-field for human Na-MRI in recent years [3-5], although the B1-field homogeneity and reproducibility can be further improved through volume resonator designs. The benefits for 129Xe [6], and 3He MRI of the human lungs [7,8] at 1.5T had been demonstrated by others. Furthermore, high SNR and maximum B1-homogeneity can be achieved with dual resonator system [9]. The aim of this study was to test and integrate the first 23Na whole body resonator on a clinical 3T system and show its advantages over common resonator approaches as a stand-alone transceiver coil and as a transmit-only resonator in conjunction with a 23Na receive-only surface coil.