Multi-scale conv-attention U-Net for medical image segmentation.

U-Net-based network structures are widely used in medical image segmentation. However, effectively capturing multi-scale features and spatial context information of complex organizational structures remains a challenge. To address this, we propose a novel network structure based on the U-Net backbone. This model integrates the Adaptive Convolution (AC) module, Multi-Scale Learning (MSL) module, and Conv-Attention module to enhance feature expression ability and segmentation performance. The AC module dynamically adjusts the convolutional kernel through an adaptive convolutional layer. This enables the model to extract features of different shapes and scales adaptively, further improving its performance in complex scenarios. The MSL module is designed for multi-scale information fusion. It effectively aggregates fine-grained and high-level semantic features from different resolutions, creating rich multi-scale connections between the encoding and decoding processes. On the other hand, the Conv-Attention module incorporates an efficient attention mechanism into the skip connections. It captures global context information using a low-dimensional proxy for high-dimensional data. This approach reduces computational complexity while maintaining effective spatial and channel information extraction. Experimental validation on the CVC-ClinicDB, MICCAI 2023 Tooth, and ISIC2017 datasets demonstrates that our proposed MSCA-UNet significantly improves segmentation accuracy and model robustness. At the same time, it remains lightweight and outperforms existing segmentation methods.