Electrical Engineering, Stanford University, Stanford, California.
Magn Reson Med. 2019 Nov;82(5):1604-1616. doi: 10.1002/mrm.27815. Epub 2019 Jun 22.
To develop a method for banding-free balanced SSFP cardiac cine imaging in a single breath-hold.
A frequency modulation scheme was designed for cardiac applications to eliminate the time normally required for steady-state stabilization between multiple phase-cycled acquisitions. Highly undersampled acquisitions were reconstructed using a model-based reconstruction that exploits redundancy both over time and between phase cycles. Performance of the methods was evaluated using both retrospective and prospective undersampling in scans with and without frequency modulation from four subjects.
The proposed methods enabled balanced SSFP cardiac cine with three effective phase cycles in only 10 heartbeats. Images acquired with frequency modulation and with standard phase cycling were of similar quality. The combination of temporal and inter-acquisition similarity constraints reduced errors by approximately 45% compared to enforcing similarity constraints over time alone.
In off-resonance conditions that preclude the acquisition of single-acquisition balanced SSFP, phase cycling can eliminate the dark bands in balanced SSFP cine cardiac imaging at the expense of some SNR efficiency. The proposed techniques permit these types of acquisitions in a single breath-hold.
开发一种无需带通的单次屏气即可实现平衡稳态自由进动（balanced steady-state free precession，SSFP）心脏电影成像的方法。
为心脏应用设计了一种频率调制方案，以消除在多次相位循环采集之间进行稳态稳定所需的时间。使用基于模型的重建方法对高度欠采样采集进行重建，该方法利用了时间和相位循环之间的冗余性。使用来自 4 名受试者的带有和不带有频率调制的扫描进行回顾性和前瞻性欠采样，评估了这些方法的性能。
所提出的方法仅用 10 个心跳即可实现具有三个有效相位循环的平衡 SSFP 心脏电影成像。带有频率调制和标准相位循环采集的图像质量相似。与仅在时间上施加相似性约束相比，施加时间和采集间相似性约束可将误差减少约 45%。
在排除单次采集平衡 SSFP 的离共振条件下，相位循环可以消除平衡 SSFP 心脏电影成像中的暗带，但代价是一些 SNR 效率的降低。所提出的技术允许在单次屏气下进行这些类型的采集。
