Figure 2: Measuring Regurgitation Fraction by Cardiac Magnetic Resonance Imaging. Panel A: Magnitude Image. Panel B: Through-plane phase contrast velocity mapping for flow quantification. Panel C: Velocity versus time curve depicting forward and reverse flow through aortic valve posttranscatheter valve replacement. Note significant regurgitation volume. Panel D: Velocity versus time curve of the same patient after undergoing valve-in-valve for significant paravalvular regurgitation. Note significant decrease in regurgitant volume.