Robust Self-Carlibrating nCPMG Acquisition: Application to Body Diffusion-Weighted Imaging
Robust Self-Carlibrating nCPMG Acquisition: Application to Body Diffusion-Weighted Imaging
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DOI：
10.1109/tmi.2017.2741421
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发表时间：
2018-01-01
影响因子：
10.6
通讯作者：
Kerr, Adam B.
中科院分区：
文献类型：
--
作者：
Gibbons, Eric K.;Le Roux, Patrick;Kerr, Adam B.
本文展示了一个强大的扩散加权单次激发快速自旋回波（SS-FSE）序列中存在显着的非共振，其中包括一个可变密度采集和自校准重建的改进。非Carr-Purcell-Meiboom-Giii（nCPMG）SS-FSE采集可稳定每个回波的主回波族和寄生回波族。这在整个回波链中保留了磁化的同相和正交分量。然而，nCPMG SS-FSE还促进正交分量的混叠，这使重构复杂化。本文提出了一种新的采集和重建方法，有效地将视场加倍，但使用部分k空间和变密度采样来提高扫描效率。该技术在体模扫描中提出，以验证SNR和对快速变化的对象相位的鲁棒性。在体内健康志愿者的例子和临床病例中显示腹部成像。这种新方法提供了与之前的nCPMG采集技术相当的SNR，并在体模扫描中提供了更均匀的表观扩散系数图。在体内扫描表明，这种方法是更强大的运动比以前的方法。所提出的重建是对nCPMG序列的改进，因为它是自动校准的，并且被证明可以准确地处理nCPMG SS-FSE序列的信号模型。
This paper demonstrates a robust diffusion-weighted single-shot fast spin echo (SS-FSE) sequence in the presence of significant off-resonance, which includes a variable-density acquisition and a self-calibrated reconstruction as improvements. A non-Carr-Purcell-Meiboom-Giii (nCPMG) SS-FSE acquisition stabilizes both the main and parasitic echo families for each echo. This preserves both the in-phase and quadrature components of the magnetization throughout the echo train. However, nCPMG SS-FSE also promotes aliasing of the quadrature component, which complicates reconstruction. A new acquisition and reconstruction approach is presented here, where the field-of-view is effectively doubled, but a partial k-space and variable density sampling is used to improve scan efficiency. The technique is presented in phantom scans to validate SNR and robustness against rapidly varying object phase. In vivo healthy volunteer examples and the clinical cases are demonstrated in abdominal imaging. This new approach provides comparable SNR to previous nCPMG acquisition techniques as well as providing more uniform apparent diffusion coefficient maps in phantom scans. In vivo scans suggest that this method is more robust against motion than previous approaches. The proposed reconstruction is an improvement to the nCPMG sequence as it is auto-calibrating and is justified to accurately treat the signal model for the nCPMG SS-FSE sequence.