UltraAD: Fine-Grained Ultrasound Anomaly Classification via Few-Shot CLIP Adaptation

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Main Authors: Zhou, Yue, Bi, Yuan, Tong, Wenjuan, Wang, Wei, Navab, Nassir, Jiang, Zhongliang
Format: Preprint
Published: 2025
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author Zhou, Yue
Bi, Yuan
Tong, Wenjuan
Wang, Wei
Navab, Nassir
Jiang, Zhongliang
author_facet Zhou, Yue
Bi, Yuan
Tong, Wenjuan
Wang, Wei
Navab, Nassir
Jiang, Zhongliang
contents Precise anomaly detection in medical images is critical for clinical decision-making. While recent unsupervised or semi-supervised anomaly detection methods trained on large-scale normal data show promising results, they lack fine-grained differentiation, such as benign vs. malignant tumors. Additionally, ultrasound (US) imaging is highly sensitive to devices and acquisition parameter variations, creating significant domain gaps in the resulting US images. To address these challenges, we propose UltraAD, a vision-language model (VLM)-based approach that leverages few-shot US examples for generalized anomaly localization and fine-grained classification. To enhance localization performance, the image-level token of query visual prototypes is first fused with learnable text embeddings. This image-informed prompt feature is then further integrated with patch-level tokens, refining local representations for improved accuracy. For fine-grained classification, a memory bank is constructed from few-shot image samples and corresponding text descriptions that capture anatomical and abnormality-specific features. During training, the stored text embeddings remain frozen, while image features are adapted to better align with medical data. UltraAD has been extensively evaluated on three breast US datasets, outperforming state-of-the-art methods in both lesion localization and fine-grained medical classification. The code will be released upon acceptance.
format Preprint
id arxiv_https___arxiv_org_abs_2506_19694
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle UltraAD: Fine-Grained Ultrasound Anomaly Classification via Few-Shot CLIP Adaptation
Zhou, Yue
Bi, Yuan
Tong, Wenjuan
Wang, Wei
Navab, Nassir
Jiang, Zhongliang
Computer Vision and Pattern Recognition
Precise anomaly detection in medical images is critical for clinical decision-making. While recent unsupervised or semi-supervised anomaly detection methods trained on large-scale normal data show promising results, they lack fine-grained differentiation, such as benign vs. malignant tumors. Additionally, ultrasound (US) imaging is highly sensitive to devices and acquisition parameter variations, creating significant domain gaps in the resulting US images. To address these challenges, we propose UltraAD, a vision-language model (VLM)-based approach that leverages few-shot US examples for generalized anomaly localization and fine-grained classification. To enhance localization performance, the image-level token of query visual prototypes is first fused with learnable text embeddings. This image-informed prompt feature is then further integrated with patch-level tokens, refining local representations for improved accuracy. For fine-grained classification, a memory bank is constructed from few-shot image samples and corresponding text descriptions that capture anatomical and abnormality-specific features. During training, the stored text embeddings remain frozen, while image features are adapted to better align with medical data. UltraAD has been extensively evaluated on three breast US datasets, outperforming state-of-the-art methods in both lesion localization and fine-grained medical classification. The code will be released upon acceptance.
title UltraAD: Fine-Grained Ultrasound Anomaly Classification via Few-Shot CLIP Adaptation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2506.19694