A Novel Distortion-Matched Anatomical Imaging Technique for High-Fidelity Functional Mapping onto a True-Brain Atlas

Motivation: To address geometric distortion in EPI, a distortion-matched anatomical sequence (namely, MP2EPI) can be used in fMRI for effortless co-registration with functional scans. However, MP2EPI also introduces geometric distortion, limiting its applicability for atlas-based analysis. Goal(s): This work proposes a novel MP2EPI scheme that simultaneously acquires reversed phase-encoding EPI, enabling effective distortion correction without increasing scan time. Approach: Visual fMRI was performed using submillimetre EPI at 7T. Functional mapping accuracy was assessed using both the original and distortion-corrected MP2EPI. Results: The distortion-corrected MP2EPI demonstrates functional mapping with a high degree of similarity to MP2RAGE, suggesting its potential use for brain atlas-based analysis. Impact: The proposed MP2EPI scheme simultaneously acquires both original and reverse phase-encoding EPI, enabling effective distortion correction in distortion-matched anatomical scans. Distortion-corrected MP2EPI enhances functional mapping for submillimetre fMRI, exhibiting greater alignment with the true-brain atlas, as measured by MP2RAGE.