Look-Closer-Then-Diagnose: Confidence-Aware Ultrasound VQA via Active Zooming

Fuente: arXiv
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Main Authors: Zhou, Yue, Wu, Erxuan, Sun, Yikang, Lee, Hongjoo, Bi, Yuan, Xu, Huixiong, Navab, Nassir, Jiang, Zhongliang
Format: Preprint
Published: 2026
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author Zhou, Yue
Wu, Erxuan
Sun, Yikang
Lee, Hongjoo
Bi, Yuan
Xu, Huixiong
Navab, Nassir
Jiang, Zhongliang
author_facet Zhou, Yue
Wu, Erxuan
Sun, Yikang
Lee, Hongjoo
Bi, Yuan
Xu, Huixiong
Navab, Nassir
Jiang, Zhongliang
contents Vision-Language Models (VLMs) have significantly advanced medical visual question answering, yet their performance in ultrasound remains suboptimal. In clinical practice, sonographers explicitly focus on lesion regions to formulate reports, though diagnostic interpretations sometimes vary due to inherent subjectivity. However, existing VLMs are not explicitly structured to interactively zoom into lesions prior to diagnosis; moreover, they typically treat annotations as unbiased ground truths, failing to account for their inherent subjectivity and ambiguity. In this paper, we propose a framework specifically designed to consider the sonographer's cognitive workflow. We first introduce a structured Zoom-then-Diagnose paradigm, which replicates the interactive search process to enable lesion-focused reasoning. Furthermore, within the Group Relative Policy Optimization (GRPO) framework, we introduce an uncertainty-aware reward derived from stochastic group-wise rollouts to estimate prediction consistency as a proxy for model confidence. Together, these two components encourage the model to reinforce accurate predictions on clear cases while remaining cautious under ambiguity. Experiments across liver, breast, and thyroid datasets show that our framework improves lesion localization by 39.3\%, demonstrating that our model has learned the ability to actively look closer and diagnose.
format Preprint
id arxiv_https___arxiv_org_abs_2605_21652
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Look-Closer-Then-Diagnose: Confidence-Aware Ultrasound VQA via Active Zooming
Zhou, Yue
Wu, Erxuan
Sun, Yikang
Lee, Hongjoo
Bi, Yuan
Xu, Huixiong
Navab, Nassir
Jiang, Zhongliang
Computer Vision and Pattern Recognition
Artificial Intelligence
Vision-Language Models (VLMs) have significantly advanced medical visual question answering, yet their performance in ultrasound remains suboptimal. In clinical practice, sonographers explicitly focus on lesion regions to formulate reports, though diagnostic interpretations sometimes vary due to inherent subjectivity. However, existing VLMs are not explicitly structured to interactively zoom into lesions prior to diagnosis; moreover, they typically treat annotations as unbiased ground truths, failing to account for their inherent subjectivity and ambiguity. In this paper, we propose a framework specifically designed to consider the sonographer's cognitive workflow. We first introduce a structured Zoom-then-Diagnose paradigm, which replicates the interactive search process to enable lesion-focused reasoning. Furthermore, within the Group Relative Policy Optimization (GRPO) framework, we introduce an uncertainty-aware reward derived from stochastic group-wise rollouts to estimate prediction consistency as a proxy for model confidence. Together, these two components encourage the model to reinforce accurate predictions on clear cases while remaining cautious under ambiguity. Experiments across liver, breast, and thyroid datasets show that our framework improves lesion localization by 39.3\%, demonstrating that our model has learned the ability to actively look closer and diagnose.
title Look-Closer-Then-Diagnose: Confidence-Aware Ultrasound VQA via Active Zooming
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2605.21652