Han Paul Kyu, Park HyunWook, Park Sung-Hong
Magnetic Resonance Imaging Laboratory, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.
Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.
Magn Reson Imaging. 2017 May;38:21-26. doi: 10.1016/j.mri.2016.12.015. Epub 2016 Dec 18.
In magnetic resonance imaging (MRI), a non-zero offset in the receiver baseline signal during acquisition results in a bright spot or a line artifact in the center of the image known as a direct current (DC) artifact. Several methods have been suggested in the past for the removal or correction of DC artifacts in MR images, however, these methods cannot be applied directly when a specific phase-cycling technique is used in the imaging sequence. In this work, we proposed a new, simple technique that enables correction of DC artifacts for any arbitrary phase-cycling imaging sequences. The technique is composed of phase unification, DC offset estimation and correction, and phase restoration. The feasibility of the proposed method was demonstrated via phantom and in vivo experiments with a multiple phase-cycling balanced steady-state free precession (bSSFP) imaging sequence. Results showed successful removal of the DC artifacts in images acquired using bSSFP with phase-cycling angles of 0°, 90°, 180°, and 270°, indicating potential feasibility of the proposed method to any imaging sequence with arbitrary phase-cycling angles.
在磁共振成像（MRI）中，采集过程中接收基线信号的非零偏移会在图像中心产生一个亮点或线状伪影，称为直流（DC）伪影。过去已经提出了几种去除或校正MR图像中DC伪影的方法，然而，当成像序列中使用特定的相位循环技术时，这些方法不能直接应用。在这项工作中，我们提出了一种新的、简单的技术，该技术能够校正任何任意相位循环成像序列中的DC伪影。该技术由相位统一、DC偏移估计与校正以及相位恢复组成。通过使用多相位循环平衡稳态自由进动（bSSFP）成像序列的体模实验和体内实验，证明了所提出方法的可行性。结果表明，在使用相位循环角度为0°、90°、180°和270°的bSSFP采集的图像中成功去除了DC伪影，表明所提出的方法对任何具有任意相位循环角度的成像序列具有潜在的可行性。
