Motion- and field-robust ultra-high-resolution whole-brain imaging enabled by servo navigation

Motivation: Even subtle involuntary motion can degrade image quality in ultra-high-resolution imaging due to long acquisition times. Goal(s): To reduce motion and dynamic field induced artifacts in ultra-high-resolution T2*-weighted imaging (0.25mm³) using servo navigators for prospective correction at 7T. Approach: Servo navigators were integrated into a segmented 3D-EPI sequence to correct motion and field variations. Involuntary motion experiments were conducted, and minimum-intensity projections were used to assess the effect of prospective correction on fine details in brain anatomy. Results: Servo navigators provide motion and field estimates with sufficiently high precision and successfully mitigate artifacts in ultra-high-resolution MRI, enabling the investigation of submillimeter brain structures. Impact: Improvements in visibility of small vessels demonstrate the capability of servo navigators to correct for small motions and field changes during ultra-high-resolution T2*-weighted whole-brain imaging (0.25mm isotropic) using 3D-EPI.