Guo Lin, Kang Lili, Wang Dandan
Department of Medical Engineering, Southern Medical University, Guangzhou, China. guolin1030@ yahoo.com.cn
Nan Fang Yi Ke Da Xue Xue Bao. 2013 Feb;33(2):239-42.
The phase information of magnetic resonance (MR) phase image can be used in many MR imaging techniques, but phase wrapping of the images often results in inaccurate phase information and phase unwrapping is essential for MR imaging techniques. In this paper we analyze the causes of errors in phase unwrapping with the commonly used Goldstein Brunch-cut algorithm and propose an improved algorithm. During the unwrapping process, masking, filtering, dipole- remover preprocessor, and the Prim algorithm of the minimum spanning tree were introduced to optimize the residues essential for the Goldstein Brunch-cut algorithm. Experimental results showed that the residues, branch-cuts and continuous unwrapped phase surface were efficiently reduced and the quality of MR phase images was obviously improved with the proposed method.
磁共振（MR）相位图像的相位信息可用于多种MR成像技术，但图像的相位包裹常常导致相位信息不准确，因此相位解包裹对于MR成像技术至关重要。本文分析了常用的Goldstein分支切割算法在相位解包裹中产生误差的原因，并提出了一种改进算法。在解包裹过程中，引入了掩蔽、滤波、偶极去除预处理器以及最小生成树的Prim算法，以优化Goldstein分支切割算法所需的残差。实验结果表明，该方法有效地减少了残差、分支切割和连续的解包裹相位表面，显著提高了MR相位图像的质量。
