Comparison between static and dynamic B0-mapping methods for accurate frequency correction of CEST in the presence of temporarily fluctuating B0 inhomogeneities at 7T

Chemical Exchange Saturation Transfer is prone to inhomogeneities of the static magnetic field (B0). Hence, accurate frequency correction is mandatory for reliable quantification. Currently established B0 correction approaches assume B0 inhomogeneities to be static during CEST experiments, but this is questionable in the presence of subject motion and scanner instabilities. Thus, we propose three different dynamic B0 correction methods for CEST that can compensate for B0 instability for each Z-spectral point separately and compare them to three established static B0 correction approaches that apply the same frequency shift to all Z-spectral points in phantom and in vivo experiments.