A method for the dynamic correction of B₀-related distortions in single-echo EPI at 7T.

ABSTRACT: We propose a method to calculate field maps from the phase of each EPI in an fMRI time series. These field maps can be used to correct the corresponding magnitude images for distortion caused by inhomogeneity in the static magnetic field. In contrast to conventional static distortion correction, in which one 'snapshot' field map is applied to all subsequent fMRI time points, our method also captures dynamic changes to B₀ which arise due to motion and respiration. The approach is based on the assumption that the non-B₀-related contribution to the phase measured by each radio-frequency coil, which is dominated by the coil sensitivity, is stable over time and can therefore be removed to yield a field map from EPI. Our solution addresses imaging with multi-channel coils a

SUBMITTER: Dymerska B 

PROVIDER: S-EPMC5832018 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature