Fig. 5

Schematic figure of contrast-intensity measurement using first-pass perfusion imaging with extrasystole and missed triggering. Contrast intensity is shown on the y-axis, and number of acquired images during first-pass perfusion on the x-axis. The blue line denotes the contrast intensity in the right ventricle; red line denotes left ventricle. The green vertical line indicates an extrasystole, and the red vertical line indicates a missed triggering. Note that the number of heart beats is affected by a missed triggering (x-axis), leading to a false number of PTBs and subsequent underestimation of the pulmonary blood volume using the PTT from pulmonary transit beats. Methods using time on the x-axis and center of gravity approaches would be less affected