使用三维圆锥叶序轨迹进行全心冠状动脉磁共振血管造影。
Whole-heart coronary MR angiography using a 3D cones phyllotaxis trajectory.
机构信息
Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California.
Department of Radiology, Stanford University, Palo Alto, California.
出版信息
Magn Reson Med. 2019 Feb;81(2):1092-1103. doi: 10.1002/mrm.27475. Epub 2018 Oct 29.
PURPOSE
To develop a 3D cones steady-state free precession sequence with improved robustness to respiratory motion while mitigating eddy current artifacts for free-breathing whole-heart coronary magnetic resonance angiography.
METHOD
The proposed sequence collects cone interleaves using a phyllotaxis pattern, which allows for more distributed k-space sampling for each heartbeat compared to a typical sequential collection pattern. A Fibonacci number of segments is chosen to minimize eddy current effects with the trade-off of an increased number of acquisition heartbeats. For verification, phyllotaxis-cones is compared to sequential-cones through simulations, phantom studies, and in vivo coronary scans with 8 subjects using 2D image-based navigators for retrospective motion correction.
RESULTS
Simulated point spread functions and moving phantom results show less coherent motion artifacts for phyllotaxis-cones compared to sequential-cones. Assessment of the right and left coronary arteries using reader scores and the image edge profile acutance vessel sharpness metric indicate superior image quality and sharpness for phyllotaxis-cones.
CONCLUSION
Phyllotaxis 3D cones results in improved qualitative image scores and coronary vessel sharpness for free-breathing whole-heart coronary magnetic resonance angiography compared to standard sequential ordering when using a steady-state free precession sequence.
目的
开发一种 3D 锥形稳态自由进动序列，在减轻自由呼吸全心脏冠状动脉磁共振血管造影中涡流伪影的同时，提高对呼吸运动的鲁棒性。
方法
所提出的序列使用叶序模式收集锥形层，与典型的顺序采集模式相比，每个心跳的 k 空间采样更加分布。选择斐波那契数列的段数以最小化涡流效应，但其代价是增加采集心跳的数量。为了验证，通过模拟、体模研究和 8 名受试者的体内冠状动脉扫描，使用基于 2D 图像的导航仪进行回顾性运动校正，将叶序锥形与顺序锥形进行比较。
结果
与顺序锥形相比，模拟点扩散函数和移动体模结果显示叶序锥形的相干运动伪影更少。使用读者评分和图像边缘轮廓锐利度血管锐利度指标评估右冠状动脉和左冠状动脉表明，叶序锥形的图像质量和锐利度更好。
结论
与标准顺序排序相比，在使用稳态自由进动序列时，叶序 3D 锥形在自由呼吸全心脏冠状动脉磁共振血管造影中可获得改善的定性图像评分和冠状动脉血管锐利度。
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