Figure 2. Schematic representation of the breath-hold turbo-field echo-planar imaging (EPI) pulse sequence used for MR flow mapping. This sequence involves two excitations (two alpha pulses) within one heart phase interval, each of which are followed by three echo-planar imaging readouts. The repetition time (TR) of 11 msec is the time it takes to acquire three k lines after one alpha pulse, and the temporal resolution of 23 msec is the shot length (tshot) of six k lines (two x repetition time). Flow-sensitive and flow-compensated images were acquired in 10 shots and resulted in an imaging duration of 20 heartbeats.