摘要
梯度平面回波成像(EPI),不但可以实现对全脑图像的迅速采集,而且对血氧水平依赖(BOLD)相关的磁化率差异(即BOLD对比)具有高度的敏感性,因而被广泛应用于功能性磁共振成像研究。但是,T2加权EPI成像在与颅骨及含气腔隙邻近的特定脑区容易受到磁敏感度伪影的影响而造成信号的缺失。既要消除磁敏感度伪影的影响,又要保持对BOLD对比较高的敏感性,对此体素、回波时间(TE)以及层面选择方向的优化筛选在实际工作中至关重要。
Not only gradient-echo planar imaging （EPI） can complete the whole-brain image acquisition as soon as possible, but also EPI is very sensitive to the blood oxygen-level dependent susceptibility defference, i.e. BOLD contrast, and therefore has been widely used in the research of functional magnetic resonance imaging. But in susceptibility-related brain area, which are near the skull base or air-filled bony cavities, T2＊ weighted EPI can be easily affected by susceptibility artifacts which lead to signal losses due to partial dephasing. In order to minimize the influence of susceptibility artifacts and keep the sensitivity to BOLD contrast, the proper selection of imaging parameter, such as voxel size, TE and slice orientation, is very important in the fMRI research and practical work.
出处
《中国医学影像技术》
CSCD
北大核心
2007年第8期1260-1262,共3页
Chinese Journal of Medical Imaging Technology
