Efficient spiral in-out and EPI balanced steady-state free precession cine imaging using a high-performance 0.55T MRI
Efficient spiral in-out and EPI balanced steady-state free precession cine imaging using a high-performance 0.55T MRI
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DOI：
10.1002/mrm.28278
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发表时间：
2020-04-14
影响因子：
3.3
通讯作者：
Campbell-Washburn, Adrienne E.
中科院分区：
文献类型：
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作者：
Restivo, Matthew C.;Ramasawmy, Rajiv;Campbell-Washburn, Adrienne E.
目的低场MRI为螺旋和EPI等信噪比高效的长读数采集提供了良好的物理特性。我们使用配备高性能硬件的0.55Tesla(T)MRI系统来增加平衡稳态自由进动(BSSFP)心脏电影采集的采样占空比和延长tR，这通常受到带状伪影的限制。方法我们利用现代MRI系统改进为0.55T，开发了用于心脏成像的高效螺旋输入输出bSSFP采集系统和用于心脏成像的EPI bSSFP采集系统。螺旋输入-输出和EPI bSSFP电影协议，在tr=8ms时，被设计为既保持时空分辨率又保持屏气长度。使用这些高采样占空比的bSSFP序列进行仿真、体模成像和健康志愿者成像研究(n=12)以评估信噪比和图像质量。结果螺旋输入输出bSSFP序列在0.55T时表现良好，图像质量良好，而EPI bSSFP序列存在运动和流动伪影。与标准笛卡尔成像相比，螺旋输入输出的射血分数无差异。此外，人体图像显示，与参考笛卡尔采集相比，使用螺旋输入输出bSSFP的心肌信噪比提高了79%+/-21%，使用EPI bSSFP的心肌信噪比提高了50%+/-14%。0.55T时螺旋输入输出可恢复1.5T时69%+/-14%的心肌信噪比。结论高效的bSSFP螺旋输入输出可在高性能的0.55T磁共振成像系统上提供高质量的心脏电影成像和信噪比恢复。
Purpose Low-field MRI offers favorable physical properties for SNR-efficient long readout acquisitions such as spiral and EPI. We used a 0.55 tesla (T) MRI system equipped with high-performance hardware to increase the sampling duty cycle and extend the TR of balanced steady-state free precession (bSSFP) cardiac cine acquisitions, which typically are limited by banding artifacts.Methods We developed a high-efficiency spiral in-out bSSFP acquisition, with zeroth- and first-gradient moment nulling, and an EPI bSSFP acquisition for cardiac cine imaging using a contemporary MRI system modified to operate at 0.55T. Spiral in-out and EPI bSSFP cine protocols, with TR = 8 ms, were designed to maintain both spatiotemporal resolution and breath-hold length. Simulations, phantom imaging, and healthy volunteer imaging studies (n = 12) were performed to assess SNR and image quality using these high sampling duty-cycle bSSFP sequences.Results Spiral in-out bSSFP performed favorably at 0.55T and generated good image quality, whereas EPI bSSFP suffered motion and flow artifacts. There was no difference in ejection fraction comparing spiral in-out with standard Cartesian imaging. Moreover, human images demonstrated a 79% +/- 21% increase in myocardial SNR using spiral in-out bSSFP and 50% +/- 14% increase in SNR using EPI bSSFP as compared with the reference Cartesian acquisition. Spiral in-out acquisitions at 0.55T recovered 69% +/- 14% of the myocardial SNR at 1.5T.Conclusion Efficient bSSFP spiral in-out provided high-quality cardiac cine imaging and SNR recovery on a high-performance 0.55T MRI system.