A Quantitative Approach for Correction of Background Counts: Determination of Left Ventricular Ejection Fraction by Radionuclide Angiocardiography

A quantitative approach for correction of background counts is described for determination of the left ventricular ejection fraction from first-pass radionuclide angiocardiography. First, the method is investigated theoretically and numerically using a mathematical model. It is demonstrated that the ejection fraction can be estimated relatively well, even in a noisy situation. Second, the method is applied to the left ventricular time-activity curves from two different regions of interest, the carefully selected and the laxly selected, and these are compared to each other. Good agreement (correlation coefficient = 0.96) for 20 patients was obtained between the ejection fractions from the carefully selected region of interest and those from the laxly selected one.