Radial k-t FOCUSS for High-Resolution Cardiac Cine MRI
Radial k-t FOCUSS for High-Resolution Cardiac Cine MRI
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DOI：
10.1002/mrm.22172
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发表时间：
2010-01-01
影响因子：
3.3
通讯作者：
Ye, Jong Chul
中科院分区：
文献类型：
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作者：
Jung, Hong;Park, Jaeseok;Ye, Jong Chul
最近已经提出了一种称为K-T Pocuss（K-T焦点不确定的系统求解器）的压缩传感动态MR技术。通过利用X-F信号的稀疏性，它优于常规的K-T BLAST/SENSE（广泛使用线性采集技术/灵敏度编码）技术。本文将此想法应用于径向轨迹，以用于高分辨率心脏电影成像。与笛卡尔轨迹相比，径向轨迹更适合于高分辨率动态MRI，因为可以解决空间分辨率和视图数量之间的权衡较小，如果由于视图有限而导致的伪像，可以解决。如笛卡尔轨迹所示，K-t焦点算法有效地去除了伪像，同时保留了高时间分辨率。用于径向轨迹的K-T焦点算法有望提高动态MRI质量。与其使用明确的格栅方法，它在应用K-T Pocuss算法之前将径向K空间采样数据转换为笛卡尔网格，而是在焦点迭代过程中使用隐式网格，以防止K-Space采样错误传播。此外，使用第一次焦点迭代后的运动估计和运动补偿来进一步稀疏残留图像。通过将额外的K-T焦点步骤应用于剩余图像，可以提高分辨率。体内实验结果表明，即使从非常有限的径向数据集中，这种新方法也可以提供高时空分辨率。 Magn Reson Med 63：68-78，2010。（C）2009 Wiley-Liss，Inc。
A compressed sensing dynamic MR technique called k-t FOCUSS (k-t FOCal Underdetermined System Solver) has been recently proposed. It outperforms the conventional k-t BLAST/SENSE (Broad-use Linear Acquisition Speed-up Technique/SENSitivity Encoding) technique by exploiting the sparsity of x-f signals. This paper applies this idea to radial trajectories for high-resolution cardiac cine imaging. Radial trajectories are more suitable for high-resolution dynamic MRI than Cartesian trajectories since there is smaller tradeoff between spatial resolution and number of views if streaking artifacts due to limited views can be resolved. As shown for Cartesian trajectories, k-t FOCUSS algorithm efficiently removes artifacts while preserving high temporal resolution. k-t FOCUSS algorithm applied to radial trajectories is expected to enhance dynamic MRI quality. Rather than using an explicit gridding method, which transforms radial k-space sampling data to Cartesian grid prior to applying k-t FOCUSS algorithms, we use implicit gridding during FOCUSS iterations to prevent k-space sampling errors from being propagated. In addition, motion estimation and motion compensation after the first FOCUSS iteration were used to further sparsify the residual image. By applying an additional k-t FOCUSS step to the residual image, improved resolution was achieved. In vivo experimental results show that this new method can provide high spatiotemporal resolution even from a very limited radial data set. Magn Reson Med 63:68-78, 2010. (C) 2009 Wiley-Liss, Inc.