UAC-Net: a unified multi-task network with aggregated contextual attention and cross-layer fusion for brain tumor segmentation and classification
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Chuanqi Cai1, Jincan Zhang1, Dongyan Zhang1
1College of Information Engineering, Henan University of Science and Technology, Luoyang, China.
Introduction:
Accurate segmentation and classification of brain tumors from magnetic resonance imaging (MRI) are critical for clinical diagnosis and treatment planning. However, existing methods typically treat these two tasks independently, failing to exploit their inherent complementarity, and often struggle to capture multi-scale contextual information essential for identifying small or irregular lesions.
Methods:
To address these limitations, this paper proposes UAC-Net, a unified multi-task learning framework built upon a U-Net backbone that jointly optimizes tumor segmentation and classification through a shared encoder. Two core modules are introduced: (1) the Aggregated Contextual Attention (ACA) module, which enhances dynamic perception of critical lesion regions by combining local sliding-window attention with global downsampling attention across all encoder levels; and (2) the Adjacent Layer Multi-scale Feature Fusion (ALMFF) module, which enables cross-level feature interaction to enrich multi-scale representations. In the segmentation branch, ALMFF-fused features are progressively upsampled to achieve precise lesion localization; in the classification branch, ACA-enhanced deep features are aggregated via global average pooling to yield robust semantic representations for tumor typing.
Results:
Experiments on two publicly available brain tumor MRI datasets demonstrate that UAC-Net achieves competitive and consistent performance compared with several representative methods. Specifically, UAC-Net obtains a classification accuracy of 98.53% and a Dice coefficient of 81.39% on the Figshare dataset, and achieves 99.07% classification accuracy and 86.61% Dice coefficient on the BRISC 2025 dataset.
Discussion:
These findings suggest that integrating contextual attention and cross-layer feature fusion within a unified multi-task framework is a promising approach for joint brain tumor segmentation and classification.