Figure 29

Gibbs ringing and myocardial perfusion. a-b) Numerical simulation of a short-axis image with an LV/myocardium signal ratio of 3: a) theoretical image with no Gibbs ringing, b) short-axis image corrupted by Gibbs ringing; notice the darker undershoot in the subendocardial border mimicking a real perfusion defect. c) The same short-axis image corrupted by Gibbs ringing but with a lower LV/myocardium contrast to simulate the signal after first-pass; the first Gibbs undershoot is not as dark as in b, and is usually not visible, hidden by the relatively high noise levels of perfusion images. d-e) in vivo short-axis example: d) an example of circumferential Gibbs ringing during the first-pass of contrast, e) the same short-axis plane after the first-pass when Gibbs ringing is no longer noticeable. f) example of Gibbs ringing in a short-axis frame of a bSSFP cine (arrow).