Iterative Method for Predistortion of MRI Gradient Waveforms
Iterative Method for Predistortion of MRI Gradient Waveforms
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DOI：
10.1109/tmi.2014.2320987
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发表时间：
2014-08-01
影响因子：
10.6
通讯作者：
Grissom, William A.
中科院分区：
文献类型：
--
作者：
Harkins, Kevin D.;Does, Mark D.;Grissom, William A.
这项工作的目的是纠正磁共振成像（MRI）中的瞬态梯度波形误差，无论是涡流，群延迟，或梯度放大器的非线性，这是众所周知的影响图像质量。提出了一种迭代方法来最小化期望的梯度波形和测量的梯度波形之间的误差，其成功不依赖于梯度系统脉冲响应的准确知识。该方法被施加到半脉冲激励的2-D超短回波时间（UTE）成像的小动物MRI系统和螺旋2-D激励的人7 T MRI系统。预失真的梯度波形减少了由激励梯度轨迹误差引起的2-D UTE中的时间信号变化，并且改善了由螺旋激励脉冲产生的激励图案的质量。迭代梯度预失真对于最小化瞬时梯度误差是有用的，而不需要梯度系统脉冲响应的精确表征。
The purpose of this work is to correct for transient gradient waveform errors in magnetic resonance imaging (MRI), whether from eddy currents, group delay, or gradient amplifier nonlinearities, which are known to affect image quality. An iterative method is proposed to minimize error between desired and measured gradient waveforms, whose success does not depend on accurate knowledge of the gradient system impulse response. The method was applied to half-pulse excitation for 2-D ultra-short echo time (UTE) imaging on a small animal MRI system and to spiral 2-D excitation on a human 7T MRI system. Predistorted gradient waveforms reduced temporal signal variation caused by excitation gradient trajectory errors in 2-D UTE, and improved the quality of excitation patterns produced by spiral excitation pulses. Iterative gradient predistortion is useful for minimizing transient gradient errors without requiring accurate characterization of the gradient system impulse response.