['The grading of pulmonary regurgitation (PR) severity by two-dimensional (2D) and Doppler echocardiography is not standardized. Cardiovascular magnetic resonance imaging is the clinical gold standard for PR quantification. The purpose of this study was to determine the best 2D and Doppler echocardiographic predictors of severe PR.', 'Thirty-six patients with tetralogy of Fallot or pulmonary valve stenosis with prior pulmonary valvuloplasty or transannular or subannular patch repair underwent 2D and Doppler echocardiography and cardiovascular magnetic resonance. Two-dimensional and Doppler echocardiographic measurements used to predict severe PR included diastolic flow reversal in the main or branch pulmonary arteries, PR jet width > or = 50% of the pulmonary annulus, PR pressure half-time < 100 ms, and PR index < 0.77.', 'With the exception of PR index, all indices were significant independent predictors of severe PR. The best univariate predictor of severe PR was branch pulmonary artery diastolic flow reversal.'] Do two-dimensional and Doppler echocardiography reliably predict severe pulmonary regurgitation as quantified by cardiac magnetic resonance?