Design of a logarithmic k-space spiral trajectory
Design of a logarithmic k-space spiral trajectory
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DOI：
10.1002/mrm.1309
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发表时间：
2001-12-01
影响因子：
3.3
通讯作者：
Gai, N
中科院分区：
文献类型：
--
作者：
Cline, HE;Zong, XL;Gai, N
螺旋采集用于快速心脏成像，因为它们有效地遍历k空间并最大限度地减少流动伪影。设计了一种变螺距对数螺旋轨迹，对k空间的低频区域进行临界采样，对高频区域逐渐欠采样。轨迹的近似解析表达式提供了一种快速计算梯度波形和采样数据点的方法。针对阿基米德-对数复合弹道，提出了一种基于弹道曲率和梯度幅值随时间变化率的数值计算方法。实现了脉冲序列，并在体模和人体心脏上采集了图像。由于k空间范围的增加和混叠伪影的减少，图像分别显示出图像分辨率的提高和图像质量的一些改善。(C)2001 Wiley-Liss，Inc.
Spiral acquisitions are used in fast cardiac imaging because they traverse k-space efficiently and minimize flow artifacts. A variable pitch logarithmic spiral trajectory is designed to critically sample the low-frequency region in k-space and gradually undersample the high-frequency region. An approximate analytical expression for the trajectory provides a fast means to calculate the gradient waveforms and the sampled data points. A numerical method is introduced based on the trajectory curvature and the rate of change in the gradient magnitude with time for the composite Archimedean-logarithmic trajectory. The pulse sequence is implemented and images are acquired on phantoms and human hearts. The images show improved image resolution and some improvement in image quality as a result of increased extent in k-space and reduction in aliasing artifacts, respectively. (C) 2001 Wiley-Liss, Inc.