Correction of breathing-induced dynamic field changes in the cervical cord using FID navigators at 3T

Motivation: To correct breathing-induced field fluctuations and ensuing artifacts on T2*-weighted MRI of the cervical cord to improve T2* mapping. Goal(s): To characterize B0 field changes caused by respiration within the cervical cord and to retrospectively compensate for those spatiotemporal fluctuations using a FID navigator-based correction technique. Approach: B0 field coefficients up to second order were measured using FID navigators and a multi-channel low-resolution reference image. Retrospective correction was performed using measured field coefficients during an iterative image reconstruction. Results: The FIDnav framework characterized the B0 field changes and improved the quality of T2*-weighted MRI and T2* maps by correcting respiratory-induced artifacts. Impact: Improved quality of T2*-weighted images, obtained after correction of respiration-induced field changes, holds promise for improving MRI techniques relying on T2* contrast (BOLD fMRI, QSM) and clinical applications in neurological diseases of the cervical cord.