A simplified technique for measuring right ventricular ejection fraction using the equilibrium radionuclide angiocardiogram and the slant-hole collimator.

Abstract

A simplified technique for measuring the right ventricular ejection fraction (RVEF) was developed. Following in vivo 99mTc red cell labeling, equilibrium (ECG-gated) radionuclide angiocardiography was performed in the modified left anterior oblique projection using a 30.degree. slant-hole collimator. A single region of interest was defined from the ejection fraction image, and background was corrected. In 11 normal patients the mean RVEF was 0.59 .+-. 0.08. In 20 patients with suspected disease, who had RVEF measured by both equilibrium and 1st-pass techniques, the correlation between the 2 methods was excellent (r = 0.95; RVEF [1st-pass] = 0.74 RVEF [equilibrium] + 0.03). Interobserver correlation was also excellent, as was the correlation between RVEF measured at least 60 min apart. This method was more accurate than alternative techniques, using either a background region of interest adjacent to the right ventricle or a fixed right ventricular region of interest which included the infundibulum. This simplified technique provides a reproducible method for the sequential quantitative assessment of right ventricular performance.