Figure 20.

Myocardial perfusion and cardiac motion artefacts (centric-interleaved phase-order). a) Numerical simulations of a short-axis image (including Gibbs ringing) with no in-plane motion. b) Same as a but with in-plane cardiac motion (myocardial radial contraction) with a centric-interleaved phase-order acquisition. c) In vivo short-axis image of a perfusion scan with an h-EPI sequence with a centric-interleaved phase-order acquisition. A typical motion artefact is visible in the septal wall. This is no longer a subendocardial dark rim as shown in the previous Figure for a sequential phase-order, but ghosting from the endocardial border offset along the phase-encode direction (arrows), similar to the numerical simulation shown in b. d) As in the previous Figure, motion artefacts are no longer visible after first-pass due to the reduction of signal contrast between the LV and myocardium.