P-LORAKS: Low-rank modeling of local k-space neighborhoods with parallel imaging data.
P-LORAKS: Low-rank modeling of local k-space neighborhoods with parallel imaging data.
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DOI：
10.1002/mrm.25717
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发表时间：
2016-04
影响因子：
3.3
通讯作者：
Zhuo J
中科院分区：
文献类型：
--
作者：
Haldar JP;Zhuo J
提出并评价一种新的无标定并行成像重建框架P-LORAKS。LORAKS是一个灵活而强大的框架，最近提出的约束MRI重建。LORAKS基于这样的观察，即当图像具有有限的支持或平滑相位时，由完全采样的k空间数据构造的某些矩阵应该具有低秩，并且可以使用低秩正则化从欠采样或噪声数据准确地重建图像。本文介绍了P-LORAKS，它扩展了LORAKS的上下文中的并行成像。这是通过将来自不同通道的LORAKS矩阵组合以产生并行成像数据的更大但更简约的低秩矩阵模型来实现的。这种新的模型可以用来正则化欠采样的并行成像数据的重建，并隐含地施加相位，支持和并行成像的约束，而不需要校准相位，支持，或灵敏度配置文件。P-LORAKS的能力进行了评估，回顾性欠采样数据，并与现有的并行MRI重建方法进行比较。结果表明，P-LORAKS可以提高并行成像重建质量，并且可以使用与现有重建方法不兼容的新的k空间轨迹。P-LORAKS框架为并行图像重建的正则化提供了一种新的有效途径。
To propose and evaluate P-LORAKS, a new calibrationless parallel imaging reconstruction framework. LORAKS is a flexible and powerful framework that was recently proposed for constrained MRI reconstruction. LORAKS was based on the observation that certain matrices constructed from fully-sampled k-space data should have low rank whenever the image has limited support or smooth phase, and made it possible to accurately reconstruct images from undersampled or noisy data using low-rank regularization. This paper introduces P-LORAKS, which extends LORAKS to the context of parallel imaging. This is achieved by combining the LORAKS matrices from different channels to yield a larger but more parsimonious low-rank matrix model of parallel imaging data. This new model can be used to regularize the reconstruction of undersampled parallel imaging data, and implicitly imposes phase, support, and parallel imaging constraints without needing to calibrate phase, support, or sensitivity profiles. The capabilities of P-LORAKS are evaluated with retrospectively undersampled data and compared against existing parallel MRI reconstruction methods. Results show that P-LORAKS can improve parallel imaging reconstruction quality, and can enable the use of new k-space trajectories that are not compatible with existing reconstruction methods. The P-LORAKS framewok provides a new and effective way to regularize parallel imaging reconstruction.