Uretsky S, et al. - Researchers assessed the recommended echocardiographic parameters against a reference modality and then tried to create and validate how each echocardiographic measure of mitral regurgitation severity should be weighed. Participants were 112 subjects who were evaluated with echocardiography and magnetic resonance imaging (MRI). The echocardiographic parameters of mitral regurgitation, as recommended by the American Society of Echocardiography, were moderately correlated with magnetic resonance imaging-derived regurgitant volume. Proximal isovelocity surface area (PISA)-derived effective regurgitant orifice area, PISA-derived regurgitant volume, flail leaflet, and left ventricular end-diastolic volume were the best predictors of MRI-RV, and so should be weighed more heavily than other parameters.