Reduction of geometric and intensity distortions in echo-planar imaging using a multireference scan
Reduction of geometric and intensity distortions in echo-planar imaging using a multireference scan
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DOI：
10.1002/mrm.1910370619
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发表时间：
1997-06-01
影响因子：
3.3
通讯作者：
Zeng, GL
中科院分区：
文献类型：
--
作者：
Wan, X;Gullberg, GT;Zeng, GL
回波平面成像（EPI）对不同解剖区域之间的磁化率变化引起的患者诱导场不均匀性非常敏感。这导致图像中的几何和强度失真，特别是在组织/空气和组织/骨界面附近。提出了一种新的方法，以减少几何和强度的EPI失真。相位编码多参考扫描用于估计由于场不均匀性引起的测量信号中的幅度和相位误差。利用测量误差的幅度和相位校正EPI数据。该技术已使用采用传统梯度实施的EPI脉冲序列以及采用具有特殊共振梯度和快速模数转换器的成像系统实施的EPI脉冲序列进行了评估。在体模和人体实验中的结果表明，在没有物体运动的情况下，新的校正技术可以有效地减少几何和强度失真。
Echo-planar imaging (EPI) is very sensitive to patient-induced field inhomogeneity caused by susceptibility changes between different anatomical regions. This results in geometric and intensity distortions in the image, especially near tissue/air and tissue/bone interfaces. A new approach is presented to reduce geometric and intensity distortions in EPI. A phase-encoded multireference scan is used to estimate the amplitude and phase errors in the measured signals due to the field inhomogeneity. The EPI data is corrected using both the amplitude and phase of the measured errors. This technique has been evaluated using EPI pulse sequences implemented with conventional gradients and implemented with imaging systems that have special resonating gradients and fast analog to digital converters. The results in both phantom and human studies show that in the absence of object motion the new correction technique can effectively reduce the geometric and intensity distortions.