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Bibliographic Details
Main Authors: Xia, Tian, Sinclair, Matthew, Schuh, Andreas, Ribeiro, Fabio De Sousa, Mehta, Raghav, Rasal, Rajat, Puyol-Antón, Esther, Gerber, Samuel, Petersen, Kersten, Schaap, Michiel, Glocker, Ben
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.21213
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Table of Contents:
  • Counterfactual image generation enables controlled data augmentation, bias mitigation, and disease modeling. However, existing methods guided by external classifiers or regressors are limited to subject-level factors (e.g., age) and fail to produce localized structural changes, often resulting in global artifacts. Pixel-level guidance using segmentation masks has been explored, but requires user-defined counterfactual masks, which are tedious and impractical. Segmentor-guided Counterfactual Fine-Tuning (Seg-CFT) addressed this by using segmentation-derived measurements to supervise structure-specific variables, yet it remains restricted to global interventions. We propose Positional Seg-CFT, which subdivides each structure into regional segments and derives independent measurements per region, enabling spatially localized and anatomically coherent counterfactuals. Experiments on coronary CT angiography show that Pos-Seg-CFT generates realistic, region-specific modifications, providing finer spatial control for modeling disease progression.