基于集成学习的神经母细胞瘤语义分割及半透明可视化

Semantic Segmentation and Semi-Transparent Visualization of Neuroblastoma Based on Ensemble Learning

  • 摘要: 神经母细胞瘤是一种形态复杂多变的肿瘤,肿瘤的位置、形状和大小差异显著,且常伴随重要解剖结构的包绕,肿瘤与周围组织的边界模糊,导致术前评估与手术规划面临巨大挑战。为提升术前诊疗的智能化与可视化水平,本文提出了一种基于集成学习的神经母细胞瘤语义分割及半透明三维可视化方法。在语义分割部分,本文基于预训练的nnU-Net架构构建了能够使用多模态医学图像作为输入的分割框架,并在推理阶段引入了一种基于验证集Dice分数的加权投票集成策略。与nnU-Net默认的等权平均集成不同,该策略根据模型性能分配融合权重,使表现更优的模型在最终预测中占据更大权重,从而在保持整体稳定性的同时提升了分割精度。本方法在SPPIN 2023挑战赛提供的儿童神经母细胞瘤数据集上开展了对比实验,该方法在Dice系数、Hausdorff距离与体积相似性等指标上均优于主流方法。此外,为进一步验证投票集成策略的有效性,我们在BraTS2021给出的脑肿瘤数据集上进行了消融实验,证明了投票策略的确实有效。在肿瘤可视化部分,本文使用了一种基于随机点采样的半透明三维可视化方法,通过将分割后的结果进行点云化,并进行多子集点云的统计融合,在无需深度排序的条件下实现快速渲染,实现了肿瘤和周围器官的半透明可视化。本文提出的可视化方案可以提升术前空间理解效率,为复杂病例的术前辅助决策提供直观、精准的视觉支持,具备良好的临床应用前景。

     

    Abstract: Neuroblastoma is a cancer originating from immature nerve cells, most commonly occurring in infants and young children. The morphology of neuroblastoma tumors is highly complex, exhibiting variations in location, shape, and size. Additionally, tumors are often located near critical anatomical structures, making it difficult to differentiate between the tumor and surrounding tissue. This complexity presents significant challenges in preoperative evaluation and surgical planning. To better assist clinicians in preoperative diagnosis and treatment, this paper proposes a neuroblastoma diagnostic and treatment support method based on semantic segmentation and 3D transparent visualization. For semantic segmentation, we develop an ensemble learning framework that leverages multiple pre-trained nnUNet architectures. Unlike the default nnU-Net configuration, which averages the outputs of multiple models equally during inference, our method introduces a Dice-weighted voting mechanism, where each model’s contribution to the final prediction is proportional to its Dice score on the validation set. This non-uniform ensemble strategy allows better-performing models to contribute more significantly to the final result, thereby improving segmentation accuracy and boundary consistency while maintaining robustness. The proposed framework is designed to support small-sample scenarios and effectively utilize multi-modal medical imaging data (e.g., T1, T2, B0, B100). To validate the method, we perform comparison experiments on the pediatric neuroblastoma dataset provided by SPPIN 2023. The results demonstrate that our method outperforms conventional baselines in terms of Dice coefficient, Hausdorff distance, and volumetric similarity. Furthermore, to evaluate the effectiveness of the proposed voting-based ensemble strategy, we applied the same weighted scheme to the BraTS 2021 brain tumor dataset, where comparable performance improvements were observed. By incorporating the semantic segmentation results, we propose a transparent visualization approach that enables clear and intuitive observation of the segmented tumor and its surrounding anatomical structures, based on a method known as stochastic point-based rendering. This rendering technique provides realistic, rapid, and semi-transparent 3D visualization of point sets by utilizing statistical algorithms to represent spatial information. Unlike conventional 3D rendering methods, which often require computationally intensive depth sorting to preserve spatial relationships, our method maintains an accurate sense of depth without relying on such processes, thereby improving efficiency while ensuring visual fidelity. In our study, we generated the point sets by sequentially reconstructing the 2D semantic segmentation outputs across image slices, effectively transforming planar segmentation data into a coherent 3D point cloud. The color of each point in the cloud is derived from semantic labels assigned to the tumor region, combined with the intrinsic coloration of the surrounding tissues, resulting in a composite visual output that preserves both anatomical realism and semantic interpretability. Through stochastic point-based rendering, both the color-coded tumor areas and adjacent anatomical structures are simultaneously visualized within a single perspective image. This unified view allows clinicians to efficiently assess the patient’s condition from just one fixed angle, without the need to manipulate the model or switch perspectives. As a result, the proposed method significantly enhances preoperative spatial understanding and the perception of anatomical relationships, supporting clinicians in fully comprehending complex pathological scenarios. Overall, this visualization strategy serves as a valuable auxiliary tool in the context of preoperative planning and decision-making, offering considerable potential for clinical application in precision diagnostics and surgical guidance.

     

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