1.5T MR直线加速器上用于MRI引导放射治疗的快速非门控五维心脏MRI
Fast ungated five-dimensional cardiac MRI on a 1.5 T MR-linac for MRI-guided radiotherapy
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中文总结 AI 辅助
研究针对室性心动过速患者立体定向心律失常射频消融受心肺运动限制问题，提出基于CMR-MOTUS框架的快速非门控5D-MRI重建方法，经模型验证和志愿者评估，能快速高质量个性化表征运动，有用于相关治疗的潜力。
中文摘要 AI 辅助
背景：目前，室性心动过速患者的立体定向心律失常射频消融（STAR）受复杂心肺运动限制。当前的5D-MRI运动模型采集和重建时间长，限制临床可行性。目的：开发一种快速、非门控的5D-MRI重建方法用于个性化运动表征，以支持MRI引导的STAR治疗。方法：提出基于CMR-MOTUS框架的快速、非门控5D-MRI重建方法。采用3D笛卡尔采集和联合优化框架重建运动校正参考图像和低秩变形矢量场（DVF），利用低秩结构在优化时明确分离呼吸和心脏运动，再用DVF进行5D-MRI重建，运动状态数量可回顾性调整。使用数字和物理心肺模型验证，并用10名健康志愿者评估，与2D电影MRI比较运动一致性。结果：数字和物理模型验证表明5D CMR-MOTUS能准确重建5D-MRI。物理模型中左心室DICE为0.96±0.01。志愿者队列中，5D-MRI扫描与2D电影MRI运动一致性强，心脏运动误差0.1±0.9mm，呼吸运动误差0.2±2.9mm。关键是，5D-MRI数据1分钟采集、6分钟重建。结论：所提5D-MRI方法能实现快速、高质量和个性化运动表征，有潜力集成到MRI引导的STAR治疗中。
英文摘要
Background: Stereotactic arrhythmia radio-ablation (STAR) for patients with ventricular tachycardia is currently limited by complex cardiorespiratory motion. Current 5D-MRI motion models require long acquisition and reconstruction times, limiting clinical viability. Objective: To develop a fast, ungated 5D-MRI reconstruction method for personalized motion characterization to support MRI-guided STAR treatments. Methods: We propose a fast, ungated 5D-MRI reconstruction method based on the CMR-MOTUS framework. The method uses a 3D Cartesian acquisition with a joint optimization framework to reconstruct a motion-corrected reference image and low-rank deformation vector fields (DVFs). By exploiting the low rank structure, we explicitly disentangle respiratory and cardiac motion during optimization. Then, the DVFs are used for 5D-MRI reconstruction with a retrospectively adjustable number of motion states. Validation was performed using digital and physical cardiorespiratory phantoms. Furthermore, the approach was evaluated using 10 healthy volunteers, comparing motion consistency with 2D cine MRI. Results: Validation of 5D CMR-MOTUS using digital and physical phantoms demonstrated accurate 5D-MRI reconstruction. In the physical phantom, 5D CMR-MOTUS achieved a left-ventricle DICE of 0.96 +/- 0.01. In the volunteer cohort, the 5D-MRI scans showed strong motion to 2D cine MRI, with a cardiac motion error of 0.1 +/- 0.9 mm and a respiratory motion error of 0.2 +/- 2.9 mm. Crucially, 5D-MRI data were acquired in 1 minute and reconstructed in 6 minutes. Conclusions: The proposed 5D-MRI method enables rapid, high-quality, and personalized motion characterization, demonstrating potential for integration into MRI-guided STAR treatments. Data Availability: The 3D k-space data and 5D reconstructions for the ten volunteers are publicly available at https://doi.org/10.5281/zenodo.21278894
