# SuCor: Susceptibility Distortion Correction via Parameter-Free and Self-Regularized Optimal Transport

arXiv: https://arxiv.org/abs/2603.16758 · HTML: https://mlsanity.com/paper/2603.16758/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
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- First posted on arXiv 17 Mar 2026.

## Abstract (arXiv)

We present SuCor, a method for correcting susceptibility induced geometric distortions in echo planar imaging (EPI) using optimal transport (OT) along the phase encoding direction. Given a pair of reversed phase encoding EPI volumes, we model each column of the distortion field as a Wasserstein-2 barycentric displacement between the opposing-polarity intensity profiles. Regularization is performed in the spectral domain using a bending-energy penalty whose strength is selected automatically via the Morozov discrepancy principle, requiring no manual tuning. On a human connectome project (HCP) dataset with left-right/right-left b0 EPI pairs and a co-registered T1 structural reference, SuCor achieves a mean volumetric mutual information of 0.341 with the T1 image, compared to 0.317 for FSL TOPUP, while running in approximately 12 seconds on a single CPU core.