基于图像域的Ghost伪影自动相位校正

回波平面成像过程中会产生Ghost伪影.抑制Ghost伪影的常用方法是利用参考扫描对实际扫描图像进行校正.本研究提出了一种无须参考扫描且基于图像域的自动相位校正方法.这种方法是对含伪影的图像作二维傅里叶变换,利用变换后的奇偶行数据分别重建图像以求取成像过程中奇偶回波之间的相位偏移.利用线性拟合或Marquardt-Levenber非线性拟合得到的无卷褶相位值对伪影图像进行校正,能有效抑制Ghost伪影.

Image-Based Method for Automated Phase Correction of Ghost

One of the most common artifacts for echo planar imaging is the ghost artifact, typically overcome with the aid of a reference scan preceding the actual image acquisition. In this work, we described an automated non-scanreference method for reducing ghost artifact using image-based correction. The two dimensional Fourier transformation of an entire data of image matrix was used to reconstruct two new images, one was reconstructed only by even rows, the other was only by odd rows, with the remaining ones zero-filled. Phase shift between even scans and odd scans can be computed by using the two images. Unwrapped phase shift gained by linear fitting or Marquardt-Levenber non-linear fitting can be used to suppress the ghost effectively.