arXiv:2501.09305eess.IVcs.CV2025-01

用时空引导扩散模型,加速动态MRI重建并提升细节恢复。

Domain-conditioned and Temporal-guided Diffusion Modeling for Accelerated Dynamic MRI Reconstruction

  • 引入时空与频率-时间先验,同步捕捉图像空间特征与时间动态。
  • 在不同采样率下,重建质量优于现有方法,尤其提升时间对齐与结构保真度。
  • 适合心脏和肺部动态MRI重建,支持笛卡尔与非笛卡尔采集数据。

目的:提出一种领域条件化与时间引导的扩散建模方法——动态扩散建模(dDiMo),用于加速动态MRI重建,使扩散过程能够表征时空信息,适用于时变多线圈笛卡尔与非笛卡尔数据。方法:dDiMo框架整合了时间分辨维度中的时序信息,实现扩散建模中帧内空间特征与帧间时间动态的同步捕捉。引入额外的时空(x-t)与自洽频域-时间(k-t)先验以引导扩散过程,确保精确的时间对齐并增强细微图像细节的恢复。为保证反向扩散过程平滑,采用非线性共轭梯度算法。该模型在两类MRI数据上测试:多线圈心脏MRI(笛卡尔采集)与自由呼吸肺部MRI(黄金角径向采集),覆盖多种欠采样率。结果:dDiMo在不同加速因子下均实现高质量重建,定性与定量评估均优于其他竞争方法,表现出更优的时间对齐与结构恢复能力。该扩散框架在处理笛卡尔与非笛卡尔采集数据方面均表现稳健,有效重建了心脏与肺部动态数据集。结论:本研究提出一种新型扩散建模方法,适用于动态MRI重建。

原文摘要 · Abstract (English)

Purpose: To propose a domain-conditioned and temporal-guided diffusion modeling method, termed dynamic Diffusion Modeling (dDiMo), for accelerated dynamic MRI reconstruction, enabling diffusion process to characterize spatiotemporal information for time-resolved multi-coil Cartesian and non-Cartesian data. Methods: The dDiMo framework integrates temporal information from time-resolved dimensions, allowing for the concurrent capture of intra-frame spatial features and inter-frame temporal dynamics in diffusion modeling. It employs additional spatiotemporal ($x$-$t$) and self-consistent frequency-temporal ($k$-$t$) priors to guide the diffusion process. This approach ensures precise temporal alignment and enhances the recovery of fine image details. To facilitate a smooth diffusion process, the nonlinear conjugate gradient algorithm is utilized during the reverse diffusion steps. The proposed model was tested on two types of MRI data: Cartesian-acquired multi-coil cardiac MRI and Golden-Angle-Radial-acquired multi-coil free-breathing lung MRI, across various undersampling rates. Results: dDiMo achieved high-quality reconstructions at various acceleration factors, demonstrating improved temporal alignment and structural recovery compared to other competitive reconstruction methods, both qualitatively and quantitatively. This proposed diffusion framework exhibited robust performance in handling both Cartesian and non-Cartesian acquisitions, effectively reconstructing dynamic datasets in cardiac and lung MRI under different imaging conditions. Conclusion: This study introduces a novel diffusion modeling method for dynamic MRI reconstruction.

动态MRI扩散模型加速成像多线圈数据

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