Keller Center for Imaging Innovation, Barrow Neurological Institute, 350 West Thomas Rd., Phoenix, Arizona 85013, USA.
Magn Reson Med. 2010 Jun;63(6):1683-90. doi: 10.1002/mrm.22327.
Timing delays between data acquisition and gradient transmission result in image degradation. This is especially true in spiral MRI, where delays can alter data in a nonuniform manner, generating significant artifact in the reconstructed data. The many methods that exist to mitigate these delays or measure the k-space coordinates require long measurement times, complicated analysis, specialized phantoms or hardware, or significant changes to the sequence of interest. A fast and simple method is proposed to measure delays on each gradient channel. It requires only minimal modification to an existing spiral sequence and can be used to measure independent delays on three gradient channels and any scan subject within six sequence repetition times. The effectiveness and accuracy of this method are analyzed.
数据采集和梯度传输之间的定时延迟会导致图像质量下降。在螺旋 MRI 中尤其如此，延迟会以不均匀的方式改变数据，从而在重建数据中产生明显的伪影。现有的许多方法可以减轻这些延迟或测量 k 空间坐标，但是这些方法需要长时间的测量、复杂的分析、专门的伪影或硬件，或者对感兴趣的序列进行重大更改。本文提出了一种快速简单的方法来测量每个梯度通道的延迟。它只需要对现有螺旋序列进行最小的修改，就可以用于测量三个梯度通道上的独立延迟，以及六个序列重复时间内的任何扫描对象。分析了该方法的有效性和准确性。
