At the speed in which EBCT images the heart: 100 msec, is almost looking at still motion.

As soon as you go to 250 msec which is even faster than a traditional spiral CT can do right now, it starts to get blurring and lose resolution.

In analyzing average motions of all the coronary arteries in one complete heart beat, LAD is the slowest moving and therefore easiest to image, circumflex moves faster, and RCA is the fastest. Thus the imaging of RCA is the hardest. During each cardiac cycle, the ideal time to image RCA corresponds to the area of lowest velocity; this point in time corresponds to end systolic or the U wave on the ECG. This period time is less than 100 msec.