arXiv:2608.06958eess.IV2026-08中稿 · MICCAI CDMRI Works…

用空间掩码集学习,从稀疏数据高保真合成扩散MRI信号。

Spatial Masked-Set Learning for Sparse Multi-Shell Diffusion MRI Signal Synthesis

论文配图:Spatial Masked-Set Learning for Sparse Multi-Shell Diffusion MRI Signal Synthesis
图 1 · 摘自论文原文
  • 将测量值视为无序集合,结合局部邻域上下文预测球谐系数。
  • 在b=1000、10个梯度输入下,信号NMSE达2.70%,优于现有模型22.4%。
  • 适合需要快速采集且高精度重建的脑白质研究者使用。

密集多壳扩散MRI虽能提供丰富的q空间信息,但采集时间长。本文提出一种基于空间掩码集的学习框架,用于稀疏多壳扩散MRI信号合成。模型将观测数据视为无序集合,利用$3 \times 3 \times 3$局部邻域获取空间上下文,预测中心体素的径向6阶SHORE系数,并可解析解码至任意q空间位置合成信号。训练融合壳级梯度丢弃、密集信号监督与旋转一致的SHORE目标,确保稀疏输入在增强下仍与系数监督对齐。在保留部分参考采集数据的HCP100脑白质体素上评估,本方法在信号NMSE上优于分析型q空间模型及最先进的连续扩散MRI信号合成模型。在b=1000设置下,仅使用10个输入梯度时,达到2.70%的NMSE,相较该连续模型相对降低22.4%。重建的b=1000信号的各向异性分数作为补充张量指标,尽管分析模型在整体信号误差较高,但在FA表现仍具竞争力。代码已开源:https://github.com/xmindflow/SHOREPred。

原文摘要 · Abstract (English)

Dense multi-shell diffusion MRI provides rich q-space information but requires long acquisition times. We propose a spatial masked-set framework for sparse multi-shell diffusion MRI signal synthesis. The model treats observed measurements as an unordered set, uses a local $3 \times 3 \times 3$ neighborhood for spatial context, and predicts radial-order-6 SHORE coefficients for the center voxel. The coefficients can then be decoded analytically to synthesize signals at arbitrary q-space locations. Training combines shell-wise gradient dropping, dense signal supervision, and rotation-consistent SHORE targets so that sparse input signals remain aligned with their coefficient supervision under augmentation. We evaluate on held-out HCP100 white-matter voxels by retaining limited subsets of measured diffusion-weighted signals from the reference acquisition. The proposed method achieves lower signal NMSE than both analytical q-space models and a state-of-the-art continuous dMRI signal synthesis model designed for arbitrary input and output q-space sampling. In the $b=1000$ setting with 10 input gradients, it achieves $2.70\%$ NMSE, a $22.4\%$ relative reduction over this continuous model. Fractional anisotropy on reconstructed $b=1000$ signals provides a complementary tensor-derived endpoint, with analytical models remaining competitive for FA despite higher dense-signal NMSE across the evaluated q-space. The implementation is available on \href{https://github.com/xmindflow/SHOREPred}{https://github.com/xmindflow/SHOREPred}.

扩散MRI信号合成稀疏采集

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