A new, simple and precise method for the determination of right ventricule forward ejection fraction in first-pass...

A new method is presented for the determination of right ventricular ejection fraction (RVEF) in first-pass radionuclide cardiography. The method is simple to apply and it provides RVEF values with an experimental standard deviation of 3.4% over the whole range of right ventricular ejection fractions. The method determines RVEF from analysis of time-activity curves from regions of interest (ROIs) over representative portions of the right atrium and the pulmonary artery (RVEFRAPA). Hence, the problem of demarcation of the right ventricle from adjacent structures is avoided. RVEFRAPA was 0.658 +/- 0.067 (mean +/- 1 S.D.) in a normal group of 36 adult women. This value was not significantly different from the RVEF of 0.641 +/- 0.072 (mean +/- 1 S.D.) determined by separate areas over the right ventricle in the end-diastole and end-systole (RVEFRVSA). In a repeatability study comprising 25 subjects covering a wide range of RVEF values, the standard deviation of RVEFRAPA was 4.4 times smaller than that of RVEFRVSA. The left ventricular ejection fraction (LVEF) determined in the equilibrium gated radionuclide cardiography following the first-pass study was 0.692 +/- 0.065 (mean +/- 1 S.D.) for the normal group. Hence, LVEF is slightly higher than RVEF in normals.