小規模・大規模情報協調型Unetによる多重モーダル頭頸部癌MRI画像における転移性リンパ節のセグメンテーション
Haoyang Zhou1,2,3, Hui Xie4, Shuchao Chen1
1School of Life & Environmental Science, Guilin University of Electronic Technology, Guilin, Guangxi, China.
Background:
An accurate assessment of metastatic lymph nodes (MLNs) in head and neck magnetic resonance imaging (MRIs) is crucial in nasopharyngeal carcinoma (NPC) staging and treatment planning. As a fundamental step in computer-aided diagnosis systems, automated MLNs segmentation remains challenging due to three key issues: the small size, blurred margins and large localization variations among patients, which often lead to over- and under-segmentation.
Purpose:
To address these challenges, the Small- and Large-scale Information Collaborative Unet (SLSIC-Unet) has been proposed. This network is specifically designed to aggregate small-scale information, modality-specific features (MSFs) and the spatial relationships across MRI slices.
Method:
The proposed SLSIC-Unet incorporates three dedicated strategies corresponding to the aforementioned challenges. First, to prevent small MLNs from being obscured by background information, a small- and large-scale information collaborative framework (SLSICF) is proposed. This framework utilizes dual interactive pathways: magnified image patches are processed to aggregate small-scale information, preventing the loss of small-area MLN representations, while raw images are simultaneously analyzed to extract large-scale contextual information, ensuring performance for general MLNs. Second, to delineate the fuzzy margins of MLNs, the SLSIC-Unet leverages complementary information across modalities by extracting both modality-specific features (MSFs) and multi-modality-fusion features. Finally, the spatial feature context module (SFCM) is designed to aggregate the spatial relationships of MRI slices, utilizing the spatial distribution tendency of MLNs which mostly exhibit proximity to blood vessels.
Results:
Evaluated on a cohort of 663 NPC cases, the proposed model achieved valuable segmentation performance, with mean values of 0.801 ± 0.098 for normalized surface distance (NSD), 0.823 ± 0.082 for dice similarity coefficient (DSC), and 0.706 ± 0.107 for intersection over union (IoU) on the test set. Comparative analysis revealed that the SLSIC-Unet significantly outperformed (p < 0.05) existing state-of-the-art methods in MLNs segmentation.
Conclusion:
The SLSIC-Unet is capable of accurately segmenting MLNs, and can provide technical support for assisting in Nstaging of nasopharyngeal carcinoma.
