MADPOT: Medical Anomaly Detection with CLIP Adaptation and Partial Optimal Transport

Medical anomaly detection (AD) is challenging due to diverse imaging modalities, anatomical variations, and limited labeled data. We propose a novel approach combining visual adapters and prompt learning with Partial Optimal Transport (POT) and contrastive learning (CL) to improve CLIP’s adaptability to medical images, particularly for AD. Unlike standard prompt learning, which often yields a single representation, our method employs multiple prompts aligned with local features via POT to capture subtle abnormalities. CL further enforces intraclass cohesion and inter-class separation. Our method achieves state-ofthe-art results in few-shot, zero-shot, and cross-dataset scenarios without synthetic data or memory banks. The code is available at https: //github.com/mahshid1998/MADPOT.