Curvilinear Structure-preserving Unpaired Cross-domain Medical Image Translation

TL;DR

This paper introduces CST, a framework that preserves fine curvilinear structures during unpaired cross-domain medical image translation, significantly improving fidelity across multiple imaging modalities.

Contribution

CST explicitly maintains curvilinear structures in unpaired translation by integrating a structure consistency module into existing models like CycleGAN and UNSB.

Findings

CST improves translation fidelity across three imaging modalities.

State-of-the-art performance achieved in preserving curvilinear structures.

Framework is seamlessly integrable into existing translation models.

Abstract

Unpaired image-to-image translation has emerged as a crucial technique in medical imaging, enabling cross-modality synthesis, domain adaptation, and data augmentation without costly paired datasets. Yet, existing approaches often distort fine curvilinear structures, such as microvasculature, undermining both diagnostic reliability and quantitative analysis. This limitation is consequential in ophthalmic and vascular imaging, where subtle morphological changes carry significant clinical meaning. We propose Curvilinear Structure-preserving Translation (CST), a general framework that explicitly preserves fine curvilinear structures during unpaired translation by integrating structure consistency into the training. Specifically, CST augments baseline models with a curvilinear extraction module for topological supervision. It can be seamlessly incorporated into existing methods. We integrate it into CycleGAN and UNSB as two representative backbones. Comprehensive evaluation across three imaging modalities: optical coherence tomography angiography, color fundus and X-ray coronary angiography demonstrates that CST improves translation fidelity and achieves state-of-the-art performance. By reinforcing geometric integrity in learned mappings, CST establishes a principled pathway toward curvilinear structure-aware cross-domain translation in medical imaging.