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引用次数: 0
摘要
目的构建并评估一种轻质、高性能、高性价比的 3.0 T MRI 系统，该系统具有增强的时空磁场特性，可用于先进的成像应用：方法：开发了重量为 1100 千克的轻型 3.0 T 无低温磁体。主要优化措施包括传导冷却通路、振动隔离、机械阻尼和结构稳定性，以确保磁场的长期稳定性。为解决残余振动问题，还开发了包含导航回波校正的定制成像序列。设计的梯度线圈具有 200 mT/m 的峰值振幅和先进的屏蔽技术，以最大限度地减少磁铁与线圈之间的相互作用。集成了被动垫片和主动垫片线圈，以提高空间磁场的均匀性：时间磁场波动降低了 99.81%，从 2.168 T 降至 0.004 T。在球形体积（DSV）直径为 180 毫米的范围内，无源垫片实现了空间峰峰值和均方根误差（RMSE）均匀性，分别为百万分之 22.41 和百万分之 3.69，通过有源垫片线圈进一步提高到百万分之 4.18 和百万分之 1.02。梯度屏蔽线圈将杂散场限制在 1.2 高斯，并减少了残余涡流场。利用自制的控制台和射频线圈构建了一套完整的磁共振成像系统。通过加速算法大大缩短了扫描时间，实现了小鼠大脑的高分辨率成像以及塑料部件和多孔介质的详细分析：结论：新开发的 3.0 T 磁共振成像系统具有卓越的时空磁场稳定性和成像能力。结论：新开发的 3.0 T 磁共振成像系统展示了卓越的时空磁场稳定性和成像能力，大大提高了图像质量和分辨率，适用于各种应用，包括小型动物研究和材料表征：意义：该无低温磁共振成像系统性能的增强代表了脑科学、塑料和多孔介质成像技术的重大进步。
Design, Fabrication and Test of a Lightweight 3.0 T Cryogen-Free MRI System with GM refrigerator for Imaging Small Animals and Materials.
Objective: To construct and evaluate a lightweight, high-performance and cost-effective 3.0 T MRI system with enhanced spatiotemporal magnetic field characteristics for advanced imaging applications.
Methods: A lightweight 3.0 T cryogen-free magnet weighing $\sim$1100 kg was developed. Key optimizations included conduction-cooled pathway, vibration isolation, mechanical damping, and structural stability to ensure long-term magnetic field stability. Customized imaging sequences incorporated navigator echo corrections were developed to address residual vibrations. A gradient coil was designed with 200 mT/m peak amplitude and advanced shielding to minimize magnet-coil interactions. Passive shimming and active shim coils were integrated to improve spatial magnetic field homogeneity.
Results: The 5 Gauss line of the superconducting magnet was constrained to 1.80 m × 1.20 m. Temporal magnetic field fluctuations were reduced by 99.81%, decreasing from 2.168 $µ$ T to 0.004 $µ$ T. Passive shimming achieved spatial peak-to-peak and root mean square error (RMSE) homogeneity of 22.41 parts per million (ppm) and 3.69 ppm over a 180 mm diameter of spherical volume (DSV), with further improvements to 4.18 ppm and 1.02 ppm through active shim coils. Gradient shield coils confined stray fields to 1.2 Gauss and reduced residual eddy fields. A complete MRI system was constructed with a home-built console and a radio frequency (RF) coil. High-resolution imaging of the mouse brain and detailed analysis of plastic parts and porous media were achieved, with accelerated algorithms reducing scan times significantly.
Conclusion: The newly developed 3.0 T MRI system demonstrates superior spatiotemporal magnetic field stability and imaging capabilities. It offers significant improvements in image quality and resolution for various applications, including small animal studies and material characterization.
Significance: The enhanced performance of this cryogen-free MR system represents a significant advancement in brain science, plastics, and porous media imaging technology.
期刊介绍：
IEEE Transactions on Biomedical Engineering contains basic and applied papers dealing with biomedical engineering. Papers range from engineering development in methods and techniques with biomedical applications to experimental and clinical investigations with engineering contributions.
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