统一处理脑结构体和表面网格的层次化变换器,提升疾病分析精度。
Hierarchical Mesh Transformers with Topology-Guided Pretraining for Morphometric Analysis of Brain Structures
- 基于单纯形复形构建自适应树分区,支持多尺度注意力机制。
- 在ADNI和MELD数据集上,阿尔茨海默病分类与致病负担预测达领先水平。
- 适用于多种神经影像特征融合,适合跨模态脑结构分析研究者。
大规模非结构化体网格与表面网格的表征学习在神经影像中面临挑战,尤其当模型需整合多种顶点级形态描述符(如皮层厚度、曲率、沟深、髓鞘含量)时,这些指标蕴含细微的疾病信号。现有方法或忽略临床信息,或仅支持单一网格拓扑,限制了其在成像流程中的应用。本文提出一种分层变换器框架,基于任意阶单纯形复形构建空间自适应树分区,统一处理体网格与表面网格,实现无需拓扑特化修改的高效多尺度注意力。特征投影模块将长度可变的顶点级临床描述符映射至空间层次,分离几何结构与特征维度,实现不同神经影像特征集的无缝集成。通过在大规模无标签队列上对坐标与形态通道进行掩码重建的自监督预训练,获得可迁移的编码主干,适用于多种下游任务与网格模态。我们在ADNI的体网格上验证阿尔茨海默病分类与淀粉样蛋白负荷预测,在MELD的皮层表面网格上验证局灶性皮层发育不良检测,所有基准均达到当前最优性能。
原文摘要 · Abstract (English)
Representation learning on large-scale unstructured volumetric and surface meshes poses significant challenges in neuroimaging, especially when models must incorporate diverse vertex-level morphometric descriptors, such as cortical thickness, curvature, sulcal depth, and myelin content, which carry subtle disease-related signals. Current approaches either ignore these clinically informative features or support only a single mesh topology, restricting their use across imaging pipelines. We introduce a hierarchical transformer framework designed for heterogeneous mesh analysis that operates on spatially adaptive tree partitions constructed from simplicial complexes of arbitrary order. This design accommodates both volumetric and surface discretizations within a single architecture, enabling efficient multi-scale attention without topology-specific modifications. A feature projection module maps variable-length per-vertex clinical descriptors into the spatial hierarchy, separating geometric structure from feature dimensionality and allowing seamless integration of different neuroimaging feature sets. Self-supervised pretraining via masked reconstruction of both coordinates and morphometric channels on large unlabeled cohorts yields a transferable encoder backbone applicable to diverse downstream tasks and mesh modalities. We validate our approach on Alzheimer's disease classification and amyloid burden prediction using volumetric brain meshes from ADNI, as well as focal cortical dysplasia detection on cortical surface meshes from the MELD dataset, achieving state-of-the-art results across all benchmarks.
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