Gated right ventricular studies using krypton-81m: comparison with first-pass studies using gold-195m.

Abstract

Krypton-81m, given by continuous i.v. infusion, has been successfully used for the equilibrium ECG-gated assessment of right ventricular function. We compared gated studies with 81mKr (half-life 13 sec) with first-pass studies using 195mAu (half-life 30.5 sec). Krypton studies analyzed using variable regions of interest (ROIs) led to a significantly higher calculated right ventricular ejection fraction (RVEF) than with a fixed ROI, both with and without background correction. The differences between first-pass studies and gated studies without background correction were significant (p less than 0.01), whereas they were not with background correction. These data suggest that large systematic errors exist in the calculation of RVEF depending on the analysis method and that background correction is important when different techniques are compared.