Ghost artifact reduction for echo planar imaging using image phase correction
Ghost artifact reduction for echo planar imaging using image phase correction
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DOI：
10.1002/mrm.1910380114
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发表时间：
1997-07-01
影响因子：
3.3
通讯作者：
Gao, LS
中科院分区：
文献类型：
--
作者：
Buonocore, MH;Gao, LS
描述了一种用于使用从仅使用偶数或奇数k空间线重建的图像导出的相位校正来减少回波平面成像（EPI）中的鬼伪影的算法。该算法在不需要校准扫描的情况下显著减少了主要由交替k空间线的时间反转引起的N/2重影。在接受EPI的8名受试者的听觉功能MRI（fMRI）实验中获得的图像中，N/2重影强度从10.3% +/-2.1%减少到10.3% +/-2.1%。从父图像强度的4.5% +/- 0.2%（范围：7.9-14.1%）到4.5% +/- 0.2%（范围：4.1-4.9%），对应于重影强度的54% +/- 9%（范围：43-65%）的百分比降低，并且算法将该强度恢复到父图像。它提供了一个显着的改善图像的外观，并增加了相关系数的神经激活功能磁共振成像研究。该算法在两个空间方向上提供了来自空间相位误差的所有多项式阶的伪影的减少。该算法没有消除由场不均匀性、磁化率或化学位移贡献的N/2鬼强度。
An algorithm is described for reducing ghost artifacts in echo planar imaging (EPI) using phase corrections derived from images reconstructed using only even or odd k-space lines. The N/2 ghost, that arises principally from time-reversal of alternate k-space lines, was significantly reduced by this algorithm without the need for a calibration scan, In images obtained in eight subjects undergoing EPI for auditory functional MRI (fMRI) experiments, N/2 ghost intensity was reduced from 10.3% +/- 2,1% (range: 7.9-14.1%) to 4.5% +/- 0.2% (range: 4.1-4.9%) of parent image intensity, corresponding to a percent reduction in ghost intensity of 54% +/- 9% (range: 43-65%), and the algorithm restored this intensity to the parent image. It provided a significant improvement in image appearance, and increased the correlation coefficients related to neural activation in functional MRI studies. The algorithm provided reduction of artifacts from all polynomial orders of spatial phase errors in both spatial directions, The algorithm did not eliminate N/2 ghost intensity contributed by field inhomogeneities, susceptibility, or chemical shift.