The invention relates to a magnetic resonance imager, which can draw out coronary artery, when the heart beat (R-R) of patient changes. Wherein, it uses the R wave at time (T0) as trigger, to scan on all code modes, that at least scanning one time at same code mode to collect data. Based on the data, data collecting time, and R wave time, the invention cuts off the image from MR time collected from the R wave (T1) next the trigger R wave, to be arranged to generate the data group of heart movement at expanding end, to rebuild image. |