Department of Radiation Oncology, Duke University, Durham, North Carolina 27710, USA.
J Magn Reson Imaging. 2010 Mar;31(3):757-65. doi: 10.1002/jmri.22069.
To accelerate non-contrast-enhanced MR angiography (MRA) with inflow inversion recovery (IFIR) with a fast imaging method, Skipped Phase Encoding and Edge Deghosting (SPEED).
IFIR imaging uses a preparatory inversion pulse to reduce signals from static tissue, while leaving inflow arterial blood unaffected, resulting in sparse arterial vasculature on modest tissue background. By taking advantage of vascular sparsity, SPEED can be simplified with a single-layer model to achieve higher efficiency in both scan time reduction and image reconstruction. SPEED can also make use of information available in multiple coils for further acceleration. The techniques are demonstrated with a three-dimensional renal non-contrast-enhanced IFIR MRA study.
Images are reconstructed by SPEED based on a single-layer model to achieve an undersampling factor of up to 2.5 using one skipped phase encoding direction. By making use of information available in multiple coils, SPEED can achieve an undersampling factor of up to 8.3 with four receiver coils. The reconstructed images generally have comparable quality as that of the reference images reconstructed from full k-space data.
As demonstrated with a three-dimensional renal IFIR scan, SPEED based on a single-layer model is able to reduce scan time further and achieve higher computational efficiency than the original SPEED.
利用快速成像方法 Skipped Phase Encoding and Edge Deghosting（SPEED），加速无对比增强磁共振血管成像（MRA）的流入反转恢复（IFIR）。
IFIR 成像使用预备反转脉冲来减少静态组织的信号，同时使流入动脉血液不受影响，从而在适度的组织背景上产生稀疏的动脉血管结构。通过利用血管稀疏性，SPEED 可以简化为单层模型，以在扫描时间减少和图像重建方面实现更高的效率。SPEED 还可以利用多个线圈中的信息进行进一步加速。该技术通过三维肾无对比增强 IFIR MRA 研究进行了演示。
图像通过 SPEED 基于单层模型进行重建，使用一个跳过的相位编码方向实现高达 2.5 的欠采样因子。通过利用多个线圈中的信息，SPEED 可以使用四个接收线圈实现高达 8.3 的欠采样因子。重建的图像通常具有与从全 k 空间数据重建的参考图像相当的质量。
正如三维肾 IFIR 扫描所示，基于单层模型的 SPEED 能够进一步减少扫描时间，并实现比原始 SPEED 更高的计算效率。
