Evaluating the effectiveness of distortion self-correction for CEST-EPI

Motivation: EPI-based CEST (CEST-EPI) is fast but suffers from image distortion caused by field susceptibility. Goal(s): We aimed to evaluate the effectiveness of using the field map generated by the Z-spectra to achieve the distortion self-correction (DISC) for single-shot CEST-EPI without additional acquisition of a field map. Approach: The effectiveness of DISC strategy was demonstrated in CEST-EPI experiments of a creatine phantom and in vivo mice. CEST-RARE was used as a reference. Results: Without acquiring an additional field map, DISC retrospectively and effectively corrected geometric distortion in CEST-EPI, leading to improved SSIM and spatial CEST contrasts. Impact: We evaluated the effectiveness of using the field map generated by the Z-spectra to achieve the distortion self-correction for single-shot CEST-EPI. Results showed that DISC retrospectively and effectively corrected geometric distortion in CEST-EPI without acquiring an additional field map.