Reduction of eddy-current-induced distortion in diffusion MRI using a twice-refocused spin echo
Reduction of eddy-current-induced distortion in diffusion MRI using a twice-refocused spin echo
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DOI：
10.1002/mrm.10308
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发表时间：
2003-01-01
影响因子：
3.3
通讯作者：
Wedeen, VJ
中科院分区：
文献类型：
--
作者：
Reese, TG;Heid, O;Wedeen, VJ
场梯度涡流引起的图像失真会在扩散加权MR图像中产生图像伪影。这些图像，通过测量由于方向依赖性扩散的NMR信号的衰减，最近已被证明是有用的急性中风的诊断和评估，并在映射的组织结构。这项工作提出了一种改进的自旋回波（SE）扩散序列，显示较少的失真，从而提高图像质量。添加第二重聚焦脉冲提供了更好的图像质量，失真更少，而扫描效率或有效性不受影响，并允许更灵活的扩散梯度定时。通过调整扩散梯度的定时，具有单个指数衰减常数的涡流可以被置零，并且具有相似衰减常数的涡流可以被大大减少。这个新的序列证明在幻影测量和扩散各向异性图像正常人脑。(C)2003 Wiley-Liss，Inc.
Image distortion due to field gradient eddy currents can create image artifacts in diffusion-weighted MR images. These images, acquired by measuring the attenuation of NMR signal due to directionally dependent diffusion, have recently been shown to be useful in the diagnosis and assessment of acute stroke and in mapping of tissue structure. This work presents an improvement on the spin-echo (SE) diffusion sequence that displays less distortion and consequently improves image quality. Adding a second refocusing pulse provides better image quality with less distortion at no cost in scanning efficiency or effectiveness, and allows more flexible diffusion gradient timing. By adjusting the timing of the diffusion gradients, eddy currents with a single exponential decay constant can be nulled, and eddy currents with similar decay constants can be greatly reduced. This new sequence is demonstrated in phantom measurements and in diffusion anisotropy images of normal human brain. (C) 2003 Wiley-Liss, Inc.