Kellner Elias, Dhital Bibek, Kiselev Valerij G, Reisert Marco
Department of Radiology, Medical Physics, University Medical Center Freiburg, Germany.
German Cancer Consortium (DKTK) & German Cancer Research Center (DKFZ), Heidelberg, Germany.
Magn Reson Med. 2016 Nov;76(5):1574-1581. doi: 10.1002/mrm.26054. Epub 2015 Nov 24.
To develop a fast and stable method for correcting the gibbs-ringing artifact.
Gibbs-ringing is a well-known artifact which manifests itself as spurious oscillations in the vicinity of sharp image gradients at tissue boundaries. The origin can be seen in the truncation of k-space during MRI data-acquisition. Correction techniques like Gegenbauer reconstruction or extrapolation methods aim at recovering these missing data. Here, we present a simple and robust method which exploits a different view on the Gibbs-phenomenon: The truncation in k-space can be interpreted as a convolution of the underlying image with a sinc-function. As the image is reconstructed on a discretized grid, the severity of the ringing artifacts depends on how this grid is located with respect to the edge and the oscillation pattern of the function. We propose to reinterpolate the image based on local, subvoxel-shifts to sample the ringing pattern at the zero-crossings of the oscillating sinc-function.
With the proposed method, the artifact can simply, effectively, and robustly be removed with a minimal amount of image smoothing.
The robustness of the method suggests it as a suitable candidate for an implementation in the standard image processing pipeline in clinical routine. Magn Reson Med 76:1574-1581, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
开发一种快速且稳定的方法来校正吉布斯振铃伪影。
吉布斯振铃是一种众所周知的伪影，在组织边界处的锐利图像梯度附近表现为虚假振荡。其根源可在磁共振成像（MRI）数据采集期间k空间的截断中看到。诸如盖根堡重建或外推法等校正技术旨在恢复这些缺失的数据。在此，我们提出一种简单且稳健的方法，该方法从不同角度看待吉布斯现象：k空间中的截断可解释为基础图像与一个 sinc 函数的卷积。由于图像是在离散化网格上重建的，振铃伪影的严重程度取决于该网格相对于函数边缘和振荡模式的位置。我们建议基于局部亚体素移位对图像进行重新插值，以在振荡的 sinc 函数的零交叉点处对振铃模式进行采样。
使用所提出的方法，只需进行最少的图像平滑处理，就能简单、有效且稳健地去除伪影。
该方法的稳健性表明它适合在临床常规的标准图像处理流程中实施。《磁共振医学》76:1574 - 1581, 2016。© 2015 国际磁共振医学学会。
