Demonstration of multi-pool quantitative CEST MRI with quasi-steady-state reconstruction – Insight into T1-independent CEST quantification

CEST quantification is challenging because the measurement depends on the scan protocols. Also, T1 normalization is not straightforward under non-equilibrium conditions. Using multi-pool simulations and phantom experiments, our study evaluated quasi-steady-state(QUASS) algorithm-boosted CEST quantification. The 3-pool CEST simulation showed significant T1 dependencies due to complex interactions among Ts, TR, and T1. Such dependencies were corrected with QUASS reconstruction. In addition, a multi-T1 phantom was used to evaluate the quantification. Whereas the apparent CEST MRI showed significant dependence on Ts, TR, and T1, accurate CEST quantification was demonstrated with the spinlock-model-based fitting of QUASS CEST MRI.