Domain-Adapted CLIP with Anatomy-Aware Synthetic Lesions for Unsupervised Chest X-Ray Anomaly Detection
摘要
To address the challenge of scarce anomalous data and insufficient annotations in medical imaging, this study proposes an Anatomic-Aware Synthetic Lesion CLIP (AASL-CLIP) framework. This method overcomes the limitations of traditional lesion synthesis approaches regarding spatial location and morphology by generating synthetic lesions constrained within lung parenchyma regions of normal chest X-rays using the proposed AnatPaste algorithm; concurrently, an adapter module is designed to accomplish feature space transformation from the natural image domain to the chest X-ray domain. Experiments on the RSNA and CheXpert datasets demonstrate that this method achieves 83.45% and 83.96% AUC on image-level detection tasks, surpassing the best baseline, MediCLIP, by 1.76% and 4.02%, respectively; the generated pixel-level heat maps exhibit high spatial correspondence with lesion regions; the synergistic effect of the AnatPaste algorithm and the adapter module significantly enhances model performance. This framework enables high-precision chest X-ray screening without the need for real anomaly annotations, providing a novel solution for unsupervised anomaly detection in chest X-rays.