首先，通过造影技术获取心脏周期内各时刻的立体图像，根据时间序列形成一组4维图像。

Firstly, a 4d image is constructed from a set of medical images that are obtained at a sequence of time points.

youdao

为延伸平均心脏周期时间的阶段而重复的每一个相位步骤使得这些得到保证，而且引起相应的数据获得时间的延长。

This may be ensured by repeating each phase step for a period extending the mean duration of the cardiac cycle and causing a corresponding extension in the acquisition time.

youdao

RF协助了了一些包括唤醒与沉睡的周期与心脏功能的过程。

The RF helps to regulate essential processes, including waking and sleeping cycles and cardiac function.

youdao

Here is as pacemaker and this pacemaker does the same thing that a heart pacemaker does, it generates periodic electrical signals.

它和心脏起搏器发挥的作用相似,发出周期性的电信号

耶鲁公开课 - 生物医学工程探索课程节选