Hybridization of Attention UNet with Repeated Atrous Spatial Pyramid Pooling for Improved Brain Tumour Segmentation

Brain tumors are highly heterogeneous in terms of their spatial and scaling characteristics, making tumor segmentation in medical images a difficult task that might result in wrong diagnosis and therapy. Automation of a task like tumor segmentation is expected to enhance objectivity, repeatability and at the same time reducing turn around time. Conventional convolutional neural networks (CNNs) exhibit sub-par performance as a result of their inability to accurately represent the range of tumor sizes and forms. Developing on that, UNets have been a commonly used solution for semantic segmentation, and it uses a downsampling-upsampling approach to segment tumors. This paper proposes a novel architecture that integrates Attention-UNet with repeated Atrous Spatial Pyramid Pooling (ASPP). ASPP effectively captures multi-scale contextual information through parallel atrous convolutions with varying dilation rates. This allows for efficient expansion of the receptive field while maintaining fine details. The attention provides the necessary context by incorporating local characteristics with their corresponding global dependencies. This integration significantly enhances semantic segmentation performance. Our approach demonstrates significant improvements over UNet, Attention UNet and Attention UNet with Spatial Pyramid Pooling allowing to set a new benchmark for tumor segmentation tasks.

Satyaki Roy Chowdhury, Golrokh Mirzaei · 2025