CE MRA的K-空间取样技术

  最简单的方法是相位编码的顺序自下而上地充填K-空间，使扫描开始时间与造影剂到达的时间一致，并在整个采集时间内持续注射造影剂。还有一种改进方法是通过选择扫描开始的时间，使K-空间中心部分的充填与动脉强化高峰一致，然后继续填充其余区域；而另一种方法涉及到中心或椭圆中心相位编码顺序，K-空间中心区域的数据最先采集，如果采集时间选择准确，则相当于动脉强化的最高峰而静脉强化却是极微的时机。

K-space sampling techniques for CE MRA

  The simplest approach is a sequential phase encoding order in which k-space lines are filled in sequence from bottom to top, with the start of the scan coinciding with the arrival of the bolus and continuous infusion of contrast throughout imaging. In a modification of this technique, sequential-order k-space filling is used but the start of scanning is timed so that peak arterial enhancement matches the acquisition of central k-space views. Another method involves centric or elliptical centric phase-encoding order; central k-space data are sampled earliest in the acquisition, which, if bolus timing is correct, will correspond to maximal peak arterial enhancement with minimal venous overlap.