Quantitative and Qualitative Evaluation of Geometric Distortion Correction in Submillimetre fMRI for Accurate Functional Mapping at 7T

Motivation: Distortion correction in EPI has been utilised in numerous fMRI studies. However, the impact of the distortion correction on submillimetre fMRI analysis remains largely unexplored. Goal(s): This work performs quantitative and qualitative evaluation of geometric distortion correction with various criteria in submillimetre fMRI at 7T. Approach: Submillimetre EPI (0.73 × 0.73 mm2) was employed for visual fMRI, and the distortion-corrected data were evaluated in terms of spatial resolution, functional mapping accuracy, and histogram distribution. Results: This work demonstrates the effectiveness of distortion correction in submillimetre fMRI, revealing substantially enhanced mapping accuracy without significant deterioration in spatial resolution or functional activation distribution. Impact: The quantitative and qualitative evaluation of EPI distortion correction presented in our work demonstrates the effectiveness of distortion correction in submillimetre fMRI at 7T, revealing substantially enhanced mapping accuracy without a significant deterioration in spatial resolution or functional activation distribution.