Factors of Variability in the Radionuclide Evaluation of Global and Regional Left Ventricular Ejection Fraction

Abstract

This study was performed to establish the normal values and range of variability for three- and five-segment regional ejection fraction analysis. In addition, file conversion was utilized to compare global values produced by different vendors’ systems. Global values show considerable differences between systems (15%-20% in most cases) which indicate the need for standardization and correction when comparing data. For regional analysis, with a mean global value of 60.6%, the mean regional ejection fractions varied from 47% to 81%. Interobserver variation of the regional parameters was between 2% and 6% (standard error of estimate) for a group of 50 “normals” (global ejection fraction >50%) with least variability in the apex and maximum in the septal segment. Intraobserver variability was between 1% and 4% with the same pattern. In a mixed population (global ejection fraction 10%–85%) all parameters exhibited more variability, and paying strict attention to patient positioning for repeat studies appears to have little effect on reducing this variation.