Accuracy and reproducibility of real-time three-dimensional echocardiography for assessment of right ventricular volumes and ejection fraction in children

Background: Measurement of right ventricular (RV) volumes and ejection fraction (EF) by two-dimensional echocardiography has limited accuracy and reproducibility because of the complex RV geometry. Objectives: This study sought to validate real-time three-dimensional echocardiography (RT3DE) using a disk summation method for assessment of RV volumes and RVEF in children by comparing it with magnetic resonance imaging (MRI) measurements. Methods: A total of 20 children (mean age 10.6 +/- 2.8 years) were studied. Transthoracic RT3DE was performed using a RT3DE system to acquire full-volume RT3DE data sets from apical windows and data were processed offline using a software package. RV end-systolic volume and end-diastolic volume (EDV) were measured using a disk summation method by manually tracing the endocardial borders. RVEF was calculated as: RVEF = (EDV - end-systolic volume)/EDV x 100%. All participants also underwent MRI studies for comparison of RV indexes. Results: Of the 20 children, 3 were excluded because of poor or incomplete RV images (two RT3DE and one MRI study). For the remaining 17 children, good correlation and agreement between RT3DE and MRI were found (RVEDV: r = 0.98, P < .001, mean difference = -7.0 +/- 9.0 mL, P < .01; RV end-systolic volume: r = 0.96, P < .001, mean difference = -3.2 +/- 7.1 mL, P > .05; RVEF: r = 0.89, P < .001, mean difference -0.3 +/- 7.1%, P > .05). The intraobserver and the interobserver variabilities ranged from -1.1% to 5.8%. Conclusion: Measurement of RV volumes and EF by RT3DE is feasible, accurate, and reproducible in children compared with MRI measurements.