Improved Susceptibility Artifact Correction of Echo-Planar MRI using the Alternating Direction Method of Multipliers
Improved Susceptibility Artifact Correction of Echo-Planar MRI using the Alternating Direction Method of Multipliers
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DOI：
10.1007/s10851-017-0757-x
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发表时间：
2018-02-01
影响因子：
2
通讯作者：
Ruthotto, Lars
中科院分区：
文献类型：
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作者：
Macdonald, Jan;Ruthotto, Lars
我们提出了一种用于回波平面成像（EPI）中磁化率伪影校正的改进技术，EPI是一种广泛应用的超快速磁共振成像（MRI）技术。我们的方法能够校正EPI图像中存在的几何变形和强度调制。我们考虑一个量身定制的变分图像配准问题，该问题纳入了物理畸变模型，旨在在可逆性约束条件下，最小化两幅反向畸变图像之间的距离。我们推导出了该变分问题一种新颖的面交错离散化方法，使得离散化的距离函数和约束条件可分离。鉴于平滑正则化项的存在会导致全局耦合，我们应用交替方向乘子法（ADMM）将该问题分解为更简单的子问题。我们证明了ADMM对于这个非凸优化问题的收敛性。对于13个高分辨率三维成像数据集，我们从校正质量和求解时间两方面展示了我们的方案相较于两种最先进方法的优越性。
We present an improved technique for susceptibility artifact correction in echo-planar imaging (EPI), a widely used ultra-fast magnetic resonance imaging (MRI) technique. Our method corrects geometric deformations and intensity modulations present in EPI images. We consider a tailored variational image registration problem incorporating a physical distortion model and aiming at minimizing the distance of two oppositely distorted images subject to invertibility constraints. We derive a novel face-staggered discretization of the variational problem that renders the discretized distance function and constraints separable. Motivated by the presence of a smoothness regularizer, which leads to global coupling, we apply the alternating direction method of multipliers (ADMM) to split the problem into simpler subproblems. We prove the convergence of ADMM for this non-convex optimization problem. We show the superiority of our scheme compared to two state-of-the-art methods both in terms of correction quality and time-to-solution for 13 high-resolution 3D imaging datasets.