A g‐factor metric for k‐t‐GRAPPA‐ and PEAK‐GRAPPA‐based parallel imaging
A g‐factor metric for k‐t‐GRAPPA‐ and PEAK‐GRAPPA‐based parallel imaging
复制标题
基于 kâtâGRAPPAâ 和 PEAKâGRAPPAâ 的并行成像的 gâfactor 度量
DOI：
10.1002/mrm.25386
复制
发表时间：
2014
影响因子：
3.3
通讯作者：
B. Jung
中科院分区：
文献类型：
--
作者：
R. Ramb;C. Binter;G. Schultz;J. Assländer;F. Breuer;M. Zaitsev;S. Kozerke;B. Jung
本研究的目的是为时间分辨k -空间并行成像方法的定量噪声和时间保真度分析提供理论框架。理论推导了噪声分布的解析形式，将现有的非时间分辨广义自校准部分并行采集（GRAPPA）的g因子公式扩展到基于时间分辨k -空间的方法。噪声分析考虑时间噪声相关性，并进一步伴随时间滤波分析。方法推导并给出了k - t - GRAPPA和PEAK - GRAPPA的所有方法。以滑动窗口重建和非时间分辨GRAPPA为参考。统计验证是基于一系列的伪副本图像。该分析在短轴心脏CINE数据集上得到了验证。结果分析证实了时间分辨平行成像方法的信噪比优于非时间分辨平行成像方法，但代价是时间频率滤波。此外，还揭示了k‐t‐GRAPPA、PEAK‐GRAPPA和滑动窗的不同时域频率滤波特性。结论本文提出的噪声行为和时间保真度分析为时间分辨重建方法的定量评价奠定了理论基础。因此，提出的理论允许时间分辨平行成像方法和非时间分辨方法之间的比较。中华医学杂志，2015,34(4):557 - 557。©2014 Wiley期刊公司
PurposeThe aim of this work is to derive a theoretical framework for quantitative noise and temporal fidelity analysis of time‐resolved k‐space‐based parallel imaging methods.TheoryAn analytical formalism of noise distribution is derived extending the existing g‐factor formulation for nontime‐resolved generalized autocalibrating partially parallel acquisition (GRAPPA) to time‐resolved k‐space‐based methods. The noise analysis considers temporal noise correlations and is further accompanied by a temporal filtering analysis.MethodsAll methods are derived and presented for k‐t‐GRAPPA and PEAK‐GRAPPA. A sliding window reconstruction and nontime‐resolved GRAPPA are taken as a reference. Statistical validation is based on series of pseudoreplica images. The analysis is demonstrated on a short‐axis cardiac CINE dataset.ResultsThe superior signal‐to‐noise performance of time‐resolved over nontime‐resolved parallel imaging methods at the expense of temporal frequency filtering is analytically confirmed. Further, different temporal frequency filter characteristics of k‐t‐GRAPPA, PEAK‐GRAPPA, and sliding window are revealed.ConclusionThe proposed analysis of noise behavior and temporal fidelity establishes a theoretical basis for a quantitative evaluation of time‐resolved reconstruction methods. Therefore, the presented theory allows for comparison between time‐resolved parallel imaging methods and also nontime‐resolved methods. Magn Reson Med 74:125–135, 2015. © 2014 Wiley Periodicals, Inc.