The structural complexity of the right ventricle has made quantitative evaluation difficult. Conventional cross-sectional echocardiographic methods are limited by geometric assumptions and the position of the planes used for imaging. Previous reports have demonstrated accurate three-dimensional echocardiographic quantitation of the right ventricle in-vitro and in experimental animals. We adapted a previously described method for three-dimensional reconstruction of the left ventricle to compute right ventricular volume and ejection fraction in a clinical setting.
We examined 29 patients aged from 2 to 42 years with pulmonary hypertension, by three-dimensional echocardiography and resonance imaging. Correlation and agreement were calculated for volumes and ejection fractions. Three-dimensional echocardiographic reconstruction, when compared to resonance imaging, yielded r values of 0.95 and 0.93, and mean differences (bias) of 31% ± 19% and 33% ± 18%, for systolic and diastolic volumes respectively. Interobserver variability was low (12.9% and 8.0%). Ejection fraction as calculated by three-dimensional echocardiography showed close agreement with resonance images (bias=l% ±7%). Three dimensional echocardiography is now a method of measuring right ventricular ejection fraction in the clinical setting which produces results comparable to those of resonance imaging. Volume measurements correlated well for systole and diastole, but consistently underestimated values produced from resonance images.