BACKGROUND : Quantitative assessment of valve regurgitation using volumetric method by comparing right and left ventricular stroke volumes is still under investigations. OBJECTIVE : To investigate the accuracy of tomographic equilibrium radionuclide ventriculography (t-ERV) for the quantification of tricuspid regurgitation (TR). RESULTS : Sixty-one patients (44 men; mean age 59 ± 12 years) who underwent both t-ERV and transthoracic echocardiography (TTE) studies within 2 weeks for right ventricular systolic function assessment were eligible for inclusion. A sub-group of 22 patients underwent both t-ERV and CMR. Patients with mitral/aortic regurgitation by TTE were excluded of the study. TR regurgitant volume (RVol) was calculated using the proximal isovelocity surface area (PISA) method from TTE and the volumetric method (right ventricular stroke volume minus left ventricular stroke volume) from t-ERV. There was a significant correlation between RVol as assess by ERV and by TTE (R = 0.95, P < 0.0001). Intraclass correlation coefficient between TTE and ERV for TR quantification was 0.95 (P < 0.0001). Among patients who underwent CMR, the correlation between RVol obtained by TTE and by t-ERV and CMR were R = 0.81 and R = 0.75, respectively (all P < 0.0001). CONCLUSIONS : TR assessment using the t-ERV correlates well with PISA from TTE in patients referred for right ventricular systolic function assessment.