Reproducibility of Right Ventricular Volumes and Ejection Fraction Using Real-time Three-Dimensional Echocardiography : Comparison With Cardiac MRI

ObjectivesThe nongeometric nature of the right ventricle (RV) makes it difficult to measure. We sought to determine whether real-time three-dimensional echocardiography (RT3DE) is superior to two-dimensional echocardiography (2DE) for the follow-up of RV function by validation vs cardiac MRI.MethodsRV volumes and ejection fraction (EF) were studied with 2DE (including area-length [A-L], the modified two-dimensional subtraction [2DS] method, and the Simpson method of discs), RT3DE, and MRI in 50 patients with left ventricular wall motion abnormalities, the results of which suggested possible RV infarction. Test-retest variation was performed by a complete restudy using a separate sonographer within 24 h without the alteration of hemodynamics or therapy. Interobserver and intraobserver variations were noted in a subgroup of 20 patients.ResultsEF estimations were similar using each technique. The mean (± SD) MRI end-diastolic volume (87 ± 22 mL) was only slightly underestimated by RT3DE (mean difference, −3 ± 10; p < 0.05), with a greater mean difference for 2DE A-L (−29 ± 10; p < 0.05), and the Simpson method of discs (−29 ± 23; p < 0.05), and was greatly overestimated by 2DS (mean difference, 26 ± 23; p < 0.05). Similarly, the mean MRI end-systolic volume (46 ± 17 mL) was only slightly underestimated by RT3DE (−4 ± 7; p < 0.05), compared with 2DE A-L (−16 ± 8; p < 0.05) and the Simpson method of discs (−16 ± 8; p < 0.05), and was overestimated by 2DS (14 ± 13; p < 0.05). RT3DE findings had a higher correlation with each parameter than any 2DE technique. There was also good intraobserver and interobserver correlation between RT3DE by two sonographers. RT3DE had less test-retest variation of RV volumes and EF than any 2DE measure.ConclusionsRT3DE is more accurate than two-dimensional approaches and reduces the test-retest variation of RV volumes and EF measurements in follow-up RV assessment.