Schulz Jessica, Korn Matthias, Deimling Michael, Semmler Wolfhard, Bock Michael
Siemens Medical Solutions, Erlangen, Germany.
MAGMA. 2008 Sep;21(5):307-15. doi: 10.1007/s10334-008-0131-5. Epub 2008 Jul 31.
Self-gating (SG) is a method to record cardiac movement during MR imaging. It uses information from an additional short, non-spatially encoded data acquisition. This usually lengthens TE and increases the sensitivity to flow artifacts. A new flow compensation scheme optimized for self-gating sequences is introduced that has very little or no time penalty over self-gating sequences without flow compensation.
Three variants of a self-gated 2D spoiled gradient echo or fast low angle shot (FLASH) sequence were implemented: without (noFC), with a conventional, serial (cFC), and with a new, time-efficient flow compensation (sFC). In experiments on volunteers and small animals, the sequence variants were compared with regard to the SG signal and the flow artifacts in the images.
Both cFC and sFC reduce flow artifacts in cardiac images. The SG signal of the sFC is more sensitive to physiological motion, so that a cardiac trigger can be extracted more precisely as in cFC. In a typical setting for small animal imaging, sFC technique reduces the echo/repetition time over cFC by about 23%/14%.
The time-efficient sFC technique provides flow-compensated images with cardiac triggering in both volunteers and small animals.
自门控（SG）是一种在磁共振成像期间记录心脏运动的方法。它利用来自额外的短时间、非空间编码数据采集的信息。这通常会延长回波时间（TE）并增加对流动伪影的敏感性。本文介绍了一种针对自门控序列优化的新的流动补偿方案，与没有流动补偿的自门控序列相比，该方案几乎没有时间代价或完全没有时间代价。
实现了自门控二维扰相梯度回波或快速小角度激发（FLASH）序列的三种变体：无流动补偿（noFC）、传统串行流动补偿（cFC）和新的高效时间流动补偿（sFC）。在志愿者和小动物实验中，比较了序列变体在自门控信号和图像中流动伪影方面的情况。
cFC和sFC均能减少心脏图像中的流动伪影。sFC的自门控信号对生理运动更敏感，因此与cFC一样，可以更精确地提取心脏触发信号。在小动物成像的典型设置中，sFC技术比cFC将回波/重复时间减少了约23%/14%。
高效时间的sFC技术在志愿者和小动物中均能提供具有心脏触发功能的流动补偿图像。
