Journal of Soft Computing and Information Technology

Journal of Soft Computing and Information Technology

Automatic Segmentation of Multiple Sclerosis Lesions on MRI Images Using Adaptive Residual U-Net

Document Type : Persian Original Article

Authors
1 Department of Engineering Sciences, Faculty of Advanced Technologies, University of Mohaghegh Ardabili, Namin, Iran.
2 Department of Bioelectric, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran.
Abstract
Multiple Sclerosis (MS) is a chronic and neurodegenerative disorder of the central nervous system, whose diagnosis, classification, and monitoring are primarily performed through Magnetic Resonance Imaging. Accurate segmentation of MS lesion boundaries plays an essential role in early diagnosis, disease severity assessment, and treatment monitoring. However, despite the reliability of manual segmentation, this process is labor-intensive, time-consuming, and requires substantial expertise. Current automated methods show limited sensitivity to small lesions and poor generalization across different acquisition parameters. A residual U-Net architecture incorporating adaptive patch extraction and hybrid loss optimization was developed. The approach combines probabilistic sampling to address class imbalance, residual connections to enhance gradient flow, and a composite Dice-Focal loss function tailored for small object segmentation. The proposed architecture was evaluated on the MSLesSeg dataset comprising 115 FLAIR sequences from 75 patients across multiple imaging centers. Experimental results demonstrate that the proposed architecture has an LTPR of 79.92%, a precision of 72.77%, a recall of 72.22%, and a Dice score of 72.49%, outperforming the classical U-Net and other compared methods in accurate and sensitive detection of MS lesions. Integration of adaptive sampling with residual U-Net architecture effectively addresses fundamental challenges in MS lesion segmentation.
Keywords

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