Søndergaard L, Ståhlberg F, Thomsen C, Spraggins T A, Gymoese E, Malmgren L, Müller E, Henriksen O
Danish Research Centre of Magnetic Resonance, Hvidovre Hospital.
Magn Reson Imaging. 1993;11(4):533-7. doi: 10.1016/0730-725x(93)90472-p.
ECG-triggered cinematographic studies of the cardiovascular system are hampered by several technical restrictions such as the inability to image end-diastole, ghosting, varying signal intensity, and phase contributions from eddy currents. Retrospective gating may solve these problems, but involves signal manipulation such as interpolating raw data from a time window. In this study, the performance of the two gating strategies was compared in quantitative MR velocity mapping on the abdominal aorta in eight healthy volunteers and on a pulsatile flow phantom. The results were compared to a one-dimensional velocity mapping technique and Doppler ultrasound. Finally, the consequence of decreasing the time window in the raw data interpolation used for retrospective gating was also examined. With retrospective gating, a low-pass filtering was seen, causing significantly prolonged duration and decreased amplitude of flow pulses. However, by reducing the time window retrospectively gated flow measurements were in good agreement with those that are ECG triggered. When fulfilling the demand of a narrow time window for interpolation, retrospective gating offers several advantages in MR velocity mapping.
心血管系统的心电图触发电影成像研究受到多种技术限制的阻碍，如无法对舒张末期进行成像、重影、信号强度变化以及涡流的相位贡献。回顾性门控或许可以解决这些问题，但需要进行信号处理，如从一个时间窗口内插值原始数据。在本研究中，对八名健康志愿者的腹主动脉以及一个脉动血流模型进行定量磁共振速度映射时，比较了两种门控策略的性能。将结果与一维速度映射技术和多普勒超声进行了比较。最后，还研究了回顾性门控中用于原始数据插值的时间窗口减小所产生的影响。采用回顾性门控时，会出现低通滤波，导致血流脉冲的持续时间显著延长且幅度减小。然而，通过回顾性地减小时间窗口，门控血流测量结果与心电图触发的测量结果高度一致。当满足插值所需的窄时间窗口要求时，回顾性门控在磁共振速度映射中具有诸多优势。
