Gradient preemphasis calibration in diffusion-weighted echo-planar imaging
Gradient preemphasis calibration in diffusion-weighted echo-planar imaging
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DOI：
10.1002/1522-2594(200010)44:4
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发表时间：
2000-10-01
影响因子：
3.3
通讯作者：
Huang, CLH
中科院分区：
文献类型：
--
作者：
Papadakis, NG;Martin, KM;Huang, CLH
本文介绍了一种方法，使快速和客观的脉冲序列特定的预加重校准，使用标准脉冲序列和系统硬件。该方法是基于k-空间测量技术，并已被应用于单次激发，扩散加权，自旋回波，回波平面成像（DW-SE-EPI），这是特别敏感的涡流引起的图像失真。该技术的效率不仅证明了涡流场的减少到可以忽略不计的水平，使用全预加重补偿，但也由这样一个事实，即调整的慢时基单独足以实际消除图像失真的DW-SE-EPI图像和随后的扩散张量地图（在一个幻影和人脑）。通过寻求直接消除EPI数据收集过程中涡流引起的相移的影响，该方法没有与DW-SE-EPI的其他涡流校正技术相关的复杂性和限制（例如采集额外的校准扫描，强烈的后处理，广泛的脉冲序列修改），使其使用冗余。(C)2000 Wiley-Liss，Inc.
This article describes a method which enables fast and objective pulse-sequence-specific preemphasis calibration, using standard pulse sequences and system hardware. The method is based on a k-space measurement technique, and has been applied to single-shot, diffusion-weighted, spin-echo, echo-planar imaging (DW-SE-EPI), which is particularly sensitive to eddy-current-induced image distortions. The efficiency of the technique was demonstrated not only by the reduction of eddy-current fields to a negligible level using full preemphasis compensation, but also by the fact that adjustment of the slow time-base alone sufficed for the practical elimination of image distortions in the DW-SE-EPI images and the subsequent diffusion tensor maps (in a phantom and a human brain). By seeking to eliminate directly the effect of eddy-current-induced phase shifts during the EPI data collection, the method is free of the complications and restrictions associated with other eddy-current correction techniques for DW-SE-EPI (such as acquisition of additional calibration scans, intense postprocessing, extensive pulse-sequence modifications), making their use redundant. (C) 2000 Wiley-Liss, Inc.