Dynamic off-resonance correction in 3D-EPI using dual FID navigators

Motivation: 3D-EPI imaging is sensitive to magnetic field (B0) fluctuations, particularly from breathing, which can cause artifacts in brain imaging. Goal(s): Our goal is to implement a straightforward technique for correcting B0 fluctuations during 3D-EPI scans. The approach targets artifacts caused by respiratory motion, aiming to improve image quality without complex post-processing. Approach: We incorporated dual FID signals into the 3D-EPI sequence, estimating and correcting frequency shifts from B0 fluctuations. Data were collected during intentional deep breathing. Results: Applying the dual FID correction significantly reduced artifacts related to breathing. The estimated B0 fluctuations correlated well with respiratory movement measurements. Impact: This correction method enables artifact reduction in 3D-EPI imaging, improving image quality for studies affected by breathing-induced B0 fluctuations. It offers potential for application in functional and structural MRI, advancing the reliability of 3D-EPI sequences for clinical and research use.