SPA: Leveraging the SAM with Spatial Priors Adapter for Enhanced Medical Image Segmentation

The Segment Anything Model (SAM) has gained renown for its success in image segmentation, benefiting significantly from its pretraining on extensive datasets and its interactive prompt-based segmentation approach. Although highly effective in natural (real-world) image segmentation tasks, the SAM model encounters significant challenges in medical imaging due to the inherent differences between these two domains. To address these challenges, we propose the Spatial Prior Adapter (SPA) scheme, a parameter-efficient fine-tuning strategy that enhances SAM's adaptability to medical imaging tasks. SPA introduces two novel modules: the Spatial Prior Module (SPM), which captures localized spatial features through convolutional layers, and the Feature Communication Module (FCM), which integrates these features into SAM's image encoder via cross-attention mechanisms. Furthermore, we develop a Multiscale Feature Fusion Module (MSFFM) to enhance SAM's end-to-end segmentation capabilities by effectively aggregating multiscale contextual information. These lightweight modules require minimal computational resources while significantly boosting segmentation performance. Our approach demonstrates superior performance in both prompt-based and end-to-end segmentation scenarios through extensive experiments on publicly available medical imaging datasets. Performance highlights the potential of the proposed method to bridge the gap between foundation models and domain-specific medical imaging tasks. This advancement paves the way for more effective AI-assisted medical diagnostic systems.