Wang Ze, Fernández-Seara María A
Center for Functional Neuroimaging and Department of Neurology, University of Pennsylvania, School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Magn Reson Med. 2006 Dec;56(6):1389-96. doi: 10.1002/mrm.21078.
Partially parallel imaging (PPI) achieves imaging acceleration by replacing partial phase encoding (PE) with the spatially localized sensitivity encoding of a receiver surface coil array. Further accelerations can be achieved through 2D PPI along two PE directions in 3D MRI. This paper is to explore the k-space-based PPI acquisition and reconstruction strategies for 3D MRI. A surrounding neighbors-based autocalibrating PPI (SNAPPI) was first presented by generalizing the 2D multicolumn multiline interpolation method. Several 2D PPI reconstruction methods were then provided by applying SNAPPI to recover the partially skipped k-space data along two PE directions separately or nonseparately, in k-space or in the hybrid k and image space. An optimal 2D PPI sampling-based reconstruction approach was also presented for applying PPI along certain spatial direction along which the array coil has not sufficient sensitivity variation for a valid PPI reconstruction. Both simulated and in vivo 2D PPI data were used to evaluate the proposed methods.
部分并行成像（PPI）通过用接收表面线圈阵列的空间定位灵敏度编码替代部分相位编码（PE）来实现成像加速。在三维磁共振成像（3D MRI）中，通过沿两个PE方向进行二维PPI可实现进一步加速。本文旨在探索用于3D MRI的基于k空间的PPI采集和重建策略。基于周围邻居的自动校准PPI（SNAPPI）首先通过推广二维多列多行插值方法提出。然后提供了几种二维PPI重建方法，通过应用SNAPPI分别或不分别在k空间或混合k和图像空间中恢复沿两个PE方向部分跳过的k空间数据。还提出了一种基于二维PPI最优采样的重建方法，用于沿阵列线圈灵敏度变化不足以进行有效PPI重建的特定空间方向应用PPI。模拟和体内二维PPI数据均用于评估所提出的方法。
