Gudbjartsson H, Patz S
Brigham and Women's Hospital, Department of Radiology, Massachusetts Institute of Technology, Boston 02115, USA.
Magn Reson Med. 1995 Oct;34(4):567-79. doi: 10.1002/mrm.1910340413.
In this paper the authors quantitatively evaluate the combined effect of both flow and diffusion in steady-state free precession (SSFP) imaging. A partition analysis (PA) is used to derive a fourth order approximation (in E2) of the signal in an echo SSFP sequence. The authors also introduce a novel very fast simulation technique, based on a circular convolution, which accurately accounts for both flow and diffusion. A 2D SSFP-echo sequence was implemented to obtain experimental data from a phantom containing three different solutions. Excellent agreement between the theory and the experimental data was found. Then by using the simulation algorithm and experimental measurements of in vivo brain motion, the authors estimated the artifacts to be expected in SSFP diffusion imaging of the brain and found them to be comparable with those of pulsed gradient spin echo. Finally, the authors point out the equivalence between the flow sensitivity of SSFP and RF spoiling commonly used in fast imaging.
在本文中，作者定量评估了稳态自由进动（SSFP）成像中流动和扩散的联合效应。采用分区分析（PA）来推导回波SSFP序列中信号的四阶近似（E2）。作者还引入了一种基于循环卷积的新型非常快速的模拟技术，该技术准确地考虑了流动和扩散。实施了二维SSFP回波序列，以从包含三种不同溶液的体模中获取实验数据。发现理论与实验数据之间具有良好的一致性。然后，通过使用模拟算法和体内脑运动的实验测量，作者估计了脑SSFP扩散成像中预期的伪影，并发现它们与脉冲梯度自旋回波的伪影相当。最后，作者指出了SSFP的流动敏感性与快速成像中常用的射频扰相之间的等效性。
