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Main Authors: Ahmed, Salma J., Mohammed, Emad A., Bidgoli, Azam Asilian
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.10508
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author Ahmed, Salma J.
Mohammed, Emad A.
Bidgoli, Azam Asilian
author_facet Ahmed, Salma J.
Mohammed, Emad A.
Bidgoli, Azam Asilian
contents Modern segmentation models achieve strong predictive performance but remain largely opaque, limiting our ability to diagnose failures, understand dataset shift, or intervene in a principled manner. We introduce Med-SegLens, a model-diffing framework that decomposes segmentation model activations into interpretable latent features using sparse autoencoders trained on SegFormer and U-Net. Through cross-architecture and cross-dataset latent alignment across healthy, adult, pediatric, and sub-Saharan African glioma cohorts, we identify a stable backbone of shared representations, while dataset shift is driven by differential reliance on population-specific latents. We show that these latents act as causal bottlenecks for segmentation failures, and that targeted latent-level interventions can correct errors and improve cross-dataset adaption without retraining, recovering performance in 70% of failure cases and improving Dice score from 39.4% to 74.2%. Our results demonstrate that latent-level model diffing provides a practical and mechanistic tool for diagnosing failures and mitigating dataset shift in segmentation models.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10508
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Med-SegLens: Latent-Level Model Diffing for Interpretable Medical Image Segmentation
Ahmed, Salma J.
Mohammed, Emad A.
Bidgoli, Azam Asilian
Computer Vision and Pattern Recognition
Modern segmentation models achieve strong predictive performance but remain largely opaque, limiting our ability to diagnose failures, understand dataset shift, or intervene in a principled manner. We introduce Med-SegLens, a model-diffing framework that decomposes segmentation model activations into interpretable latent features using sparse autoencoders trained on SegFormer and U-Net. Through cross-architecture and cross-dataset latent alignment across healthy, adult, pediatric, and sub-Saharan African glioma cohorts, we identify a stable backbone of shared representations, while dataset shift is driven by differential reliance on population-specific latents. We show that these latents act as causal bottlenecks for segmentation failures, and that targeted latent-level interventions can correct errors and improve cross-dataset adaption without retraining, recovering performance in 70% of failure cases and improving Dice score from 39.4% to 74.2%. Our results demonstrate that latent-level model diffing provides a practical and mechanistic tool for diagnosing failures and mitigating dataset shift in segmentation models.
title Med-SegLens: Latent-Level Model Diffing for Interpretable Medical Image Segmentation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2602.10508