Evaluation of left ventricular performance by gated radionuclide angiography

Gated radionuclide angiography (RVG) in orthogonal projections was used to evaluate left ventricular volume, ejection fraction, and segmental wall motion. Images of the left ventricle at end-diastole and end-systole were outlined in two projections using a simple manual method. The perimeter drawings were digitized on a desktop computer, interfaced to an XY recorder and left ventricular volumes and ejection fraction calculated. The results were compared to contrast left ventriculography (CVG) in the same projections. RVG and CVG gave similar results for end-diastolic volume (r = .87, P less than 0.001), end-systolic volume (r = .95, P less than 0.001), and ejection fraction (r = .89, P less than 0.001) over a wide range of values. In 92% of all left ventricular segments analyzed, RVG and CVG showed only minor differences in the analysis of wall motion. Reproducibility of the method by a trained observer was excellent. Interobserver trials demonstrated that less well-trained observers consistently over- or underestimated volumes, emphasizing the need for prior experience in RVG analysis. Use of this manual method for analysis of gated equilibrium RVG in orthogonal projections appears to be a reasonably accurate, reproducible method for evaluating left ventricular function.