Distortion-Free Diffusion Imaging Using Self-Navigated Cartesian Echo-Planar Time Resolved Acquisition and Joint Magnitude and Phase Constrained Reconstruction.
Distortion-Free Diffusion Imaging Using Self-Navigated Cartesian Echo-Planar Time Resolved Acquisition and Joint Magnitude and Phase Constrained Reconstruction.
复制标题
使用自由的笛卡尔回声平面时间解决采集和关节幅度以及相位约束重建的无变形扩散成像。
DOI：
10.1109/tmi.2021.3104291
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发表时间：
2022-01
影响因子：
10.6
通讯作者：
McNab JA
中科院分区：
文献类型：
--
作者：
Dai E;Lee PK;Dong Z;Fu F;Setsompop K;McNab JA
回波平面时间分辨成像（EPTI）是一种利用多激发EPI（ms-EPI）读出获得高质量无失真图像的有效方法。与传统的ms-EPI采集一样，当将EPTI合并到扩散准备脉冲序列中时，激发间相位变化是一个主要挑战。本研究的目的是开发一种自导航的笛卡尔EPTI（scEPTI）采集以及幅度和相位约束重建的无失真扩散成像。设计了一种自导航的基于笛卡尔EPTI的扩散准备脉冲序列。分析了EPTI弥散信号中的不同相位成分，提出了一种用于激发间相位校正的全相位匹配导航器的合成方法。最后，EPTI包含比传统的ms-EPI更丰富的幅度和相位信息，例如沿着时间维度的幅度和相位相关性。这些幅度和相位的相关性，以提高重建的潜力进行了探讨。比较了有无相位匹配以及有无相位或幅度约束的重建结果。与无相位匹配的重建方法相比，该方法可以提高炮间相位校正的精度，减少最终扩散图像中的信号失真。幅度约束通过抑制背景噪声并由此增加SNR来进一步改善图像质量，而相位约束可以减轻由于添加幅度约束而可能的图像模糊。所提出的EPTI设计提供的高质量无失真扩散图像和同时扩散弛豫成像能力代表了用于组织微观结构的临床和神经科学评估的非常有价值的工具。
Echo-planar time resolved imaging (EPTI) is an effective approach for acquiring high-quality distortion-free images with a multi-shot EPI (ms-EPI) readout. As with traditional ms-EPI acquisitions, inter-shot phase variations present a main challenge when incorporating EPTI into a diffusion-prepared pulse sequence. The aim of this study is to develop a self-navigated Cartesian EPTI-based (scEPTI) acquisition together with a magnitude and phase constrained reconstruction for distortion-free diffusion imaging. A self-navigated Cartesian EPTI-based diffusion-prepared pulse sequence is designed. The different phase components in EPTI diffusion signal are analyzed and an approach to synthesize a fully phase-matched navigator for the inter-shot phase correction is demonstrated. Lastly, EPTI contains richer magnitude and phase information than conventional ms-EPI, such as the magnitude and phase correlation along the temporal dimension. The potential of these magnitude and phase correlations to enhance the reconstruction is explored. The reconstruction results with and without phase matching and with and without phase or magnitude constraints are compared. Compared with reconstruction without phase matching, the proposed phase matching method can improve the accuracy of inter-shot phase correction and reduce signal corruption in the final diffusion images. Magnitude constraints further improve image quality by suppressing the background noise and thereby increasing SNR, while phase constraints can mitigate possible image blurring from adding magnitude constraints. The high-quality distortion-free diffusion images and simultaneous diffusion-relaxometry imaging capacity provided by the proposed EPTI design represent a highly valuable tool for both clinical and neuroscientific assessments of tissue microstructure.