arXiv:2502.20333eess.IVcs.CV2025-02

通过融合心脏T1弛豫模型优化采样轨迹,实现更快更准的心肌T1映射。

T1-PILOT: Optimized Trajectories for T1 Mapping Acceleration

  • 将T1信号弛豫模型嵌入采样与重建流程,联合学习非笛卡尔轨迹。
  • 在CMRxRecon数据集上,加速比提升至4倍时仍保持高保真度,PSNR和VIF显著优于基线。
  • 适合需要高精度心肌组织定量分析的临床研究与影像算法开发者。

心脏T1映射可提供心肌组织成分的定量信息,有助于评估纤维化、炎症和水肿等病理。然而,心脏固有的动态特性对扫描时间有严格限制,高分辨率T1映射仍是长期挑战。压缩感知(CS)通过欠采样k-space并从部分数据中重建图像,缩短了扫描时间;近期研究表明,联合优化欠采样模式与重建网络能显著提升性能。但当前多数T1映射流程仍依赖静态的手工设计掩码,未能充分挖掘加速与精度潜力。本文提出T1-PILOT:一种端到端方法,将T1信号弛豫模型显式引入采样-重建框架,指导非笛卡尔轨迹学习、跨帧对齐及T1衰减估计。在CMRxRecon数据集上的大量实验表明,T1-PILOT显著优于多个基线策略(包括学习型单掩码及固定径向或黄金角采样),在更高加速因子下实现更高的T1图保真度。尤其在峰值信噪比(PSNR)和视觉信息保真度(VIF)方面持续领先,且在分辨细微心肌结构方面表现突出。结果表明,结合物理弛豫模型优化采样轨迹,可同时提升定量精度并减少采集时间。

原文摘要 · Abstract (English)

Cardiac T1 mapping provides critical quantitative insights into myocardial tissue composition, enabling the assessment of pathologies such as fibrosis, inflammation, and edema. However, the inherently dynamic nature of the heart imposes strict limits on acquisition times, making high-resolution T1 mapping a persistent challenge. Compressed sensing (CS) approaches have reduced scan durations by undersampling k-space and reconstructing images from partial data, and recent studies show that jointly optimizing the undersampling patterns with the reconstruction network can substantially improve performance. Still, most current T1 mapping pipelines rely on static, hand-crafted masks that do not exploit the full acceleration and accuracy potential. In this work, we introduce T1-PILOT: an end-to-end method that explicitly incorporates the T1 signal relaxation model into the sampling-reconstruction framework to guide the learning of non-Cartesian trajectories, crossframe alignment, and T1 decay estimation. Through extensive experiments on the CMRxRecon dataset, T1-PILOT significantly outperforms several baseline strategies (including learned single-mask and fixed radial or golden-angle sampling schemes), achieving higher T1 map fidelity at greater acceleration factors. In particular, we observe consistent gains in PSNR and VIF relative to existing methods, along with marked improvements in delineating finer myocardial structures. Our results highlight that optimizing sampling trajectories in tandem with the physical relaxation model leads to both enhanced quantitative accuracy and reduced acquisition times.

医学影像T1映射压缩感知轨迹优化

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