Quasi-steady-state (QUASS) CEST solution improves the accuracy of CEST quantification – QUASS CEST MRI-based omega plot analysis

CEST MRI omega plot quantifies the labile proton fraction ratio (fr) and exchange rate (ksw), yet it assumes long RF saturation time (Ts) and relaxation delay (Td). Our study aimed to test if a quasi-steady-state (QUASS) CEST analysis that accounts for the effect of finite Ts and Td could improve the accuracy of CEST MRI quantification. Both simulation and CEST MRI experiments confirmed that the QUASS solution enabled robust quantification of ksw and fr, superior over the omega plot analysis based on the conventional apparent CEST MRI measurements.