AI 中文总结
该研究提出一种基于~50 mT永磁体的开源便携式低场MRI参考系统，集成云原生平台与Pulseq序列，经双站点验证可实现高可重复性与定量对比，支持跨站点研究及技术协作开发。
AI 中文摘要
尽管便携式低场MRI系统重新受到关注，但实现床旁应用的路径仍具挑战性，限制了其在各研究团队中的应用。不完整的文档阻碍了可重复性，导致重复设计并使跨系统比较复杂化。此外，非标准化的测试与表征给临床研究的伦理审批带来了困难。我们提出一种用于便携式低场MRI的开源参考系统，旨在支持复制、可重复性、基准测试和定量比较。该系统完全开源，基于~50 mT永磁体，集成了云原生采集平台。基于Pulseq的校准、表征和成像序列对噪声水平、涡流、基于图像的信噪比（SNR）及几何精度进行了评估。开发了定量T1、T2和B0映射序列并与参考值进行了评估。比较了两个独立复制站点的初步结果。该系统的噪声水平为热噪声基底的1.4倍，所有梯度通道的涡流衰减常数为27-32微秒。视场内的几何偏差低于2毫米。独立复制间的基于图像的SNR一致。测得的T1值与指定值匹配度高，平均绝对误差为3.1(1.8)%，而T2值被高估了10.4(5.8)%。模拟显示两种量的误差均极小，表明T2映射存在实验误差来源。该参考系统将公开文档的硬件、软件、校准程序、体模、定量MRI和模拟工具整合为一个可重复的生态系统，旨在支持跨站点可比性、可重复研究以及未来便携式低场MRI技术的协作开发。
英文摘要
Despite its renewed attention, the pathway to point-of-care portable low-field MRI systems remains challenging, limiting adoption across research groups. Incomplete documentation limits reproducibility, causing redesign and complicating cross-system comparison. Moreover, non-standardized testing and characterization complicates ethical approval for clinical studies. We present an open-source reference system for portable low-field MRI designed to support replication, reproducibility, benchmarking, and quantitative comparison. The system is fully open source, based on a ~50 mT permanent magnet, and integrated with a cloud-native acquisition platform. Pulseq-based calibration, characterization, and imaging sequences assessed noise level, eddy currents, image-based SNR, and geometric accuracy. Quantitative T1, T2, and B0 mapping sequences were developed and evaluated against reference values. Initial results from independent replications at two sites were compared. The system reached a noise level of 1.4 relative to the thermal noise floor and short eddy-current decay constants of 27-32 us across all gradient channels. Geometric deviations were below 2 mm over the field of view. Image-based SNR were consistent between the independent replications. Measured T1 values closely matched specified values, with an average absolute error of 3.1(1.8)%, while T2 values were overestimated by 10.4(5.8)%. Simulations showed only marginal errors for both quantities, suggesting experimental error sources for T2 mapping. The reference system combines openly documented hardware, software, calibration procedures, phantoms, quantitative MRI, and simulation tools in a reproducible ecosystem, aiming to support cross-site comparability, reproducible research, and collaborative development of future portable low-field MRI technologies.
Comments23 pages, 11 figures
