Multi-center comparison of whole-brain high-resolution CEST mapping at ultra-high field using PUSHUP saturation

Motivation: CEST suffers from saturation inhomogeneities, especially at ultra-high fields. Universal pulses enable calibration-free mitigation of these inhomogeneities. However, it is not obvious how well PUSHUP translates to different scanners. Goal(s): The goal of this work is to evaluate the feasibility of PUSHUP-CEST to obtain homogeneous whole-brain, high-resolution CEST maps in multi-center studies. Approach: PUSHUP was calculated using a joined database of three sites. Multiple CEST measurements were performed at each site. The mean CEST amplitudes were compared in four brain segments. Results: The resulting CEST maps were homogeneous and without major image artifacts. No significant bias could be found between sites. Impact: PUSHUP allows for high-resolution, whole-brain CEST mapping at 7T. The feasibility of PUSHUP saturation for multi-center CEST studies and the use of joined databases for pulse calculation are demonstrated. No site-bias is found. This fosters CEST mapping in large-scale studies.