Skare S, Andersson J L
Department of Clinical Neuroscience, MR Center, SE-171 76 Stockholm, Sweden.
Magn Reson Imaging. 2001 Oct;19(8):1125-8. doi: 10.1016/s0730-725x(01)00415-5.
To reduce image artifacts in diffusion tensor imaging using single shot EPI, cardiac gating may be performed to prevent brain motion induced signal void in the DWI data. In this work the necessity of performing cardiac gating with single shot echo planar imaging has been explored using F statistics of the variance in DWI data. Peripheral measurement of the cardiac cycle has been employed because of its greater convenience, and hence use, compared to ECG gating. Four volunteers have been studied. Six different trigger delays have been evaluated in the range 18-500 ms relative the peripheral pulse wave. Brain motion was found significant in and inferior to the corpus callosum area. A trigger delay of 500 ms was found to be optimal. However, a long delay allows only for one slice per R-R interval. Therefore, a minimum trigger delay may be the best choice in terms of SNR per unit of experiment time.
为减少使用单次激发EPI的扩散张量成像中的图像伪影，可进行心脏门控以防止DWI数据中脑运动引起的信号缺失。在这项工作中，利用DWI数据方差的F统计量探讨了单次激发回波平面成像进行心脏门控的必要性。由于外周心动周期测量比心电图门控更方便，因此采用了外周心动周期测量。研究了四名志愿者。在相对于外周脉搏波18 - 500 ms的范围内评估了六种不同的触发延迟。发现胼胝体区域及其下方的脑运动显著。发现500 ms的触发延迟是最佳的。然而，长延迟每个R - R间期仅允许采集一层图像。因此，就单位实验时间的信噪比而言，最小触发延迟可能是最佳选择。
