Correcting frequency and phase offsets in MRS data using robust spectral registration.
Correcting frequency and phase offsets in MRS data using robust spectral registration.
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DOI：
10.1002/nbm.4368
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发表时间：
2020-10
影响因子：
2.9
通讯作者：
Edden RAE
中科院分区：
文献类型：
--
作者：
Mikkelsen M;Tapper S;Near J;Mostofsky SH;Puts NAJ;Edden RAE
提出了一种磁振子数据中频率和相位偏移的回溯校正算法。该算法被称为鲁棒谱配准（rSR），包含一组子程序，即使在显著的频率和相位偏移或不稳定的脂质污染和残余水信号的情况下，也可以对给定数据集中的单个瞬态进行鲁棒对齐。通过复杂的多路编辑方法获得的具有不同亚谱剖面的数据也可以精确对齐。当需要时，首先应用自动去除不稳定的脂质污染和残留的水信号。利用非线性最小二乘优化，将每个瞬态信号以统计最优顺序对齐到加权平均参考点，从而在时域内校正频率和相位偏移。在编辑的数据集中，子光谱的对准是使用一种方法来执行的，该方法专门针对频域中的减影伪影。然后使用加权平均进行信号平均，以降低质量较差的瞬态的权重。在1个模拟和67个体内儿童GABA−/ gsh编辑的HERMES数据集上评估算法性能，并与先前开发的用于对齐HERMES数据的多步校正方法的性能进行比较。通过将估计的频率/相位偏移与模拟数据集的已知值进行比较，或通过检查体内数据中减法伪影的存在，对新方法的性能进行了定量评估。光谱质量在鲁棒对准后得到改善，特别是在显著光谱失真的情况下。在64%的GABA差谱和75%的GSH差谱中，rSR比多步法减少了更多的减法伪影。rSR克服了频率和相位校正的主要挑战。
An algorithm for retrospective correction of frequency and phase offsets in MRS data is presented. The algorithm, termed robust spectral registration (rSR), contains a set of subroutines designed to robustly align individual transients in a given dataset even in cases of significant frequency and phase offsets or unstable lipid contamination and residual water signals. Data acquired by complex multiplexed editing approaches with distinct subspectral profiles are also accurately aligned. Automated removal of unstable lipid contamination and residual water signals is applied first, when needed. Frequency and phase offsets are corrected in the time domain by aligning each transient to a weighted average reference in a statistically optimal order using nonlinear least-squares optimization. The alignment of subspectra in edited datasets is performed using an approach that specifically targets subtraction artifacts in the frequency domain. Weighted averaging is then used for signal averaging to down-weight poorer-quality transients. Algorithm performance was assessed on one simulated and 67 in vivo pediatric GABA−/GSH-edited HERMES datasets and compared with the performance of a multistep correction method previously developed for aligning HERMES data. The performance of the novel approach was quantitatively assessed by comparing the estimated frequency/phase offsets against the known values for the simulated dataset or by examining the presence of subtraction artifacts in the in vivo data. Spectral quality was improved following robust alignment, especially in cases of significant spectral distortion. rSR reduced more subtraction artifacts than the multistep method in 64% of the GABA difference spectra and 75% of the GSH difference spectra. rSR overcomes the major challenges of frequency and phase correction.
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影响因子：
2.2
作者：
Carlos Cobas, J.;Bernstein, Michael A.;Garcia Tahoces, Pablo
通讯作者：
Garcia Tahoces, Pablo
影响因子：
2.2
作者：
Cleve, Marianne;Kraemer, Martin;Reichenbach, Juergen R.
通讯作者：
Reichenbach, Juergen R.
影响因子：
6.2
作者：
Martin, Manon;Legat, Benoit;Govaerts, Bernadette
通讯作者：
Govaerts, Bernadette
DOI：
10.1007/s002160000404
发表时间：
2000-07-01
期刊：
FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY
影响因子：
--
作者：
Shao, XG;Pang, CY;Su, QD
通讯作者：
Su, QD
3T 下大分子抑制 GABA 编辑的前瞻性频率校正。
影响因子：
4.4
作者：
Edden, Richard A. E.;Oeltzschner, Georg;Harris, Ashley D.;Puts, Nicolaas A. J.;Chan, Kimberly L.;Boer, Vincent O.;Schar, Michael;Barker, Peter B.
通讯作者：
Barker, Peter B.