Gradient waveform pre-emphasis based on the gradient system transfer function
Gradient waveform pre-emphasis based on the gradient system transfer function
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DOI：
10.1002/mrm.27147
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发表时间：
2018-10-01
影响因子：
3.3
通讯作者：
Koestler, Herbert
中科院分区：
文献类型：
--
作者：
Stich, Manuel;Wech, Tobias;Koestler, Herbert
目的：采用梯度系统传递函数(GSTF)来描述图像重建中的k-空间轨迹。这项工作的目的是使用GSTF来确定未失真的梯度输出和预期的k空间轨迹的预加重。方法：仅使用标准MR硬件来确定MR系统的GSTF，而不使用现场探头或现场摄像机等特殊设备。GSTF用于图像重建中的轨迹预测和梯度波形预加重。作为测试序列，实现了具有相位编码梯度调制的梯度回波序列和具有螺旋读出轨迹的梯度回波序列，并将其应用于结构体模和活体头部测量。结果：基于GSTF的预加重成功地抑制了图像伪影。对于使用基于GSTF的轨迹后校正作为图像重建的一部分而获得的图像，获得了相同的结果。结论：对两个序列的伪影抑制结果表明，GSTF可以用于新的预加重。基于GSTF信息的预加重可以应用于任何任意序列类型。
Purpose: The gradient system transfer function (GSTF) has been used to describe the distorted k-space trajectory for image reconstruction. The purpose of this work was to use the GSTF to determine the pre-emphasis for an undistorted gradient output and intended k-space trajectory.Methods: The GSTF of the MR system was determined using only standard MR hardware without special equipment such as field probes or a field camera. The GSTF was used for trajectory prediction in image reconstruction and for a gradient waveform pre-emphasis. As test sequences, a gradient-echo sequence with phase-encoding gradient modulation and a gradient-echo sequence with a spiral read-out trajectory were implemented and subsequently applied on a structural phantom and in vivo head measurements.Results: Image artifacts were successfully suppressed by applying the GSTF-based pre-emphasis. Equivalent results are achieved with images acquired using GSTF-based post-correction of the trajectory as a part of image reconstruction. In contrast, the pre-emphasis approach allows reconstruction using the initially intended trajectory.Conclusion: The artifact suppression shown for two sequences demonstrates that the GSTF can serve for a novel pre-emphasis. A pre-emphasis based on the GSTF information can be applied to any arbitrary sequence type.