Gelman Neil, Silavi Ally, Anazodo Udunna
Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada; Department of Medical Imaging, University of Western Ontario, London, Ontario, Canada; Department of Lawson Health Research Institute, London, Ontario, Canada.
Department of Lawson Health Research Institute, London, Ontario, Canada.
Magn Reson Imaging. 2014 Jun;32(5):590-3. doi: 10.1016/j.mri.2014.02.011. Epub 2014 Feb 14.
A hybrid strategy for geometric distortion correction of echo-planar images is demonstrated. This procedure utilizes standard field mapping for signal displacement correction and the so-called reverse gradient acquisition for signal intensity correction. (The term reverse gradient refers to an acquisition of two sets of echo-planar images with phase encoding gradients of opposite polarity.) The hybrid strategy is applied to human brain echo-planar images acquired with and without diffusion-weighting. A comparison of the hybrid distortion corrected images to those corrected with standard field mapping only demonstrates much better performance of the hybrid method. A variant of the hybrid method is also demonstrated which requires the acquisition of only one pair of opposite polarity images within a set of images.
本文展示了一种用于回波平面图像几何失真校正的混合策略。该过程利用标准场映射进行信号位移校正，并使用所谓的反向梯度采集进行信号强度校正。（术语“反向梯度”是指采集两组具有相反极性相位编码梯度的回波平面图像。）该混合策略应用于在有和没有扩散加权的情况下采集的人脑回波平面图像。将混合失真校正图像与仅用标准场映射校正的图像进行比较，结果表明混合方法具有更好的性能。还展示了混合方法的一种变体，该变体在一组图像中仅需要采集一对相反极性的图像。
