Parallel imaging reconstruction using automatic regularization
Parallel imaging reconstruction using automatic regularization
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DOI：
10.1002/mrm.10718
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发表时间：
2004-03-01
影响因子：
3.3
通讯作者：
Wald, LL
中科院分区：
文献类型：
--
作者：
Lin, FH;Kwong, KK;Wald, LL
MRI中增加的时空分辨率可以通过使用并行采集策略来实现，该并行采集策略使用来自多个接收器的信息来同时采样减少的k空间数据以重建全FOV图像。并行MRI时空分辨率提高的代价是最终重建图像的信噪比（SNR）下降。当来自多个接收器的信息的空间相关性质使在全FOV图像的重建中使用的矩阵求逆不稳定时，部分SNR降低。在这项工作中，提出了一种基于吉洪诺夫正则化的重建算法，该算法减少了由于阵列线圈元件的空间信息中的几何相关性而导致的SNR损失。参考扫描被用作关于最终重建图像的先验信息，以使用L曲线技术为重建提供正则化估计。该自动正则化方法在双重灵敏度编码（SENSE）加速中将来自双通道阵列的体模图像中的平均g因子从1.47降低到0.80。八通道系统的体内解剖图像显示，在2.67倍加速下，平均g因子降低1.22至0.84。(C)2004 Wiley-Liss，Inc.
Increased spatiotemporal resolution in MRI can be achieved by the use of parallel acquisition strategies, which simultaneously sample reduced k-space data using the information from multiple receivers to reconstruct full-FOV images. The price for the increased spatiotemporal resolution in parallel MRI is the degradation of the signal-to-noise ratio (SNR) in the final reconstructed images. Part of the SNR reduction results when the spatially correlated nature of the information from the multiple receivers destabilizes the matrix inversion used in the reconstruction of the full-FOV image. In this work, a reconstruction algorithm based on Tikhonov regularization is presented that reduces the SNR loss due to geometric correlations in the spatial information from the array coil elements. Reference scans are utilized as a priori information about the final reconstructed image to provide regularized estimates for the reconstruction using the L-curve technique. This automatic regularization method reduces the average g-factors in phantom images from a two-channel array from 1.47 to 0.80 in twofold sensitivity encoding (SENSE) acceleration. In vivo anatomical images from an eight-channel system show an averaged g-factor reduction of 1.22 to 0.84 in 2.67-fold acceleration. (C) 2004 Wiley-Liss, Inc.