He Wei, Zhang Yu, Ding Junling, Zhao Linman
Department of Computer Science and Technology, Xinyang Normal University, Xinyang 464000, China.
Henan University of Chinese Medicine, Zhengzhou 450046, China.
Int J Biomed Imaging. 2020 Nov 18;2020:8846220. doi: 10.1155/2020/8846220. eCollection 2020.
The phase cycling method is a state-of-the-art method to reconstruct complex-valued MR image. However, when it follows practical two-dimensional (2D) subsampling Cartesian acquisition which is only enforcing random sampling in the phase-encoding direction, a number of artifacts in magnitude appear. A modified approach is proposed to remove these artifacts under practical MRI subsampling, by adding one-dimensional total variation (TV) regularization into the phase cycling method to "pre-process" the magnitude component before its update. Furthermore, an operation used in SFISTA is employed to update the magnitude and phase images for better solutions. The results of the experiments show the ability of the proposed method to eliminate the ring artifacts and improve the magnitude reconstruction.
相位循环方法是一种用于重建复值磁共振图像的先进方法。然而,当它遵循实际的二维(2D)子采样笛卡尔采集方式(仅在相位编码方向上强制随机采样)时,会出现一些幅度伪影。提出了一种改进方法,通过在相位循环方法中添加一维全变差(TV)正则化,在实际磁共振成像子采样情况下对幅度分量进行“预处理”,以去除这些伪影。此外,采用了一种在SFISTA中使用的操作来更新幅度和相位图像,以获得更好的解决方案。实验结果表明,该方法能够消除环形伪影并改善幅度重建。