B1 inhomogeneity mitigated chemical exchange saturation transfer imaging using tailored saturation pulses

Motivation: The application of CEST imaging is hampered by B1 inhomogeneities, leading to spatially varying image contrast. Goal(s): To mitigate the influence of B1 inhomogeneity on CEST images. Approach: A new CEST saturation module is proposed by introducing an amplitude and a 'Δω' frequency modulation, with coefficients optimized from Bloch simulations. Results: The feasibility of the proposed method was evaluated using phantom and healthy volunteer experiments. The proposed method provides more homogeneous results on both phantom and volunteer images than conventional Gaussian saturation. Impact: A new method to mitigate the influence of B1 inhomogeneity for CEST imaging is provided. The method has the advantage of being easy to implement and not increasing the acquisition duration.