Figure 1.
An example of a 2 half-echo projection acquisition trajectory is shown beginning at the center of k-space, moving to the edge of k-space, making a small rotation in the angular position, and then returning to the center of k-space along a new projection angle. The accompanying pulse sequence diagram is shown below with the RF pulse and idealized gradients. The k-space trajectory for a 4 half-echo projection trajectory is also shown along with the corresponding pulse sequence diagram. Note the improved data collection efficiency in time.