Brain Tumor Segmentation in MRI Images with 3D U-Net and Contextual Transformer
Thien-Qua T. Nguyen, Hieu-Nghia Nguyen, Thanh-Hieu Bui, Thien B. Nguyen-Tat, Vuong M. Ngo
TL;DR
This work addresses accurate brain tumor segmentation in multi-modal MRI by integrating a 3D Contextual Transformer (CoT) into a 3D-UNet backbone to capture long-range dependencies across modalities. The 3D CoT module computes static and dynamic contextual keys to enhance self-attention, while a Dice plus cross-entropy loss jointly optimizes segmentation. On BraTS2019, the proposed 3D-UNet+CoT achieves ET $82.0\%$, TC $81.5\%$, and WT $89.0\%$ Dice scores, with a mean Dice improvement of $2.2\%$ and $HD_{95}$ reduction of $1.1$ mm, outperforming several state-of-the-art methods. The study also analyzes modality contributions and confirms that each MRI modality adds distinct information for accurate delineation, particularly emphasizing the role of T1c and FLAIR. Overall, the approach demonstrates strong accuracy and suggests future work in preprocessing optimization, computational efficiency, and broader medical-imaging applications.
Abstract
This research presents an enhanced approach for precise segmentation of brain tumor masses in magnetic resonance imaging (MRI) using an advanced 3D-UNet model combined with a Context Transformer (CoT). By architectural expansion CoT, the proposed model extends its architecture to a 3D format, integrates it smoothly with the base model to utilize the complex contextual information found in MRI scans, emphasizing how elements rely on each other across an extended spatial range. The proposed model synchronizes tumor mass characteristics from CoT, mutually reinforcing feature extraction, facilitating the precise capture of detailed tumor mass structures, including location, size, and boundaries. Several experimental results present the outstanding segmentation performance of the proposed method in comparison to current state-of-the-art approaches, achieving Dice score of 82.0%, 81.5%, 89.0% for Enhancing Tumor, Tumor Core and Whole Tumor, respectively, on BraTS2019.
