Imaging the beating heart is a challenge for MR imaging. To capture an image of the heart that is unaffected by motion would require an image to be acquired in just a few tens of milliseconds. In Chap. 8 it was shown that the minimum possible image acquisition time is limited by the repetition time and the need to acquire a sufficient number of phase encoding steps to achieve a particular image matrix size and therefore spatial resolution. To achieve an image acquisition in a few tens of milliseconds means both limiting the number of phase encoding steps (and thus the spatial resolution and SNR), and making the TR as short as possible. As Chap. 15 on Fast Imaging will show, this can be done but only at the cost of accepting a significant reduction in image quality. One of the current main focuses of the development of MR technology is to devise imaging schemes that allow the fastest possible imaging whilst maintaining acceptable image quality.