Acquire quantifiable images to characterize rapidly moving cardiac anatomy, by selecting a line of the B-Mode image, and observing it as a function of time, enabling measurements of speed and acceleration. Imaging the left ventricle, for example, the Vevo 770 pulses rapidly (up to 1,000 times per second) and its M-Mode displays a representation of the motion of the heart wall, the thickness of the heart wall and the diameter of the chamber.