Spillover Correction for Quantification of Pulsed-CEST Experiments

Moritz Zaiss¹, Olga Ivchenko¹, Peter Bachert¹

Chemical exchange saturation transfer (CEST) effect of endogenous CEST agents with small frequency offset from water resonance like amide protons (APT) are always diluted by direct saturation of water protons (spillover effect). An analytical spillover correction is presented which allows reconstructing the unperturbed pulsed-proton transfer rate for different flip angles and B₁ using only label and reference scan. Additionally, the artificial pulsed-proton transfer rate is shown to be correlated with the analytical cw proton transfer rate. Therefore, the spillover correction provides analytic quantification of pulsed saturation transfer experiments which are feasible in clinical scanners.