Count-based scintigraphic method to calculate ventricular volumes in children: in vitro and clinical validation

Exercise radionuclide right ventriculography in children

Supine exercise equilibrium radionuclide right ventriculography was performed in 13 children (8-18 years) with hypercholesterolemia. Phase analysis was used to construct right ventricular regions of interest, and a peri-right ventricular region was used for background correction. Right ventricular ejection fraction at rest and exercise was 50.5 +/- 9.2% and 61.5 +/- 8.1%, respectively, with a mean increase of 11.0 +/- 7.5 percentage units (range 1-27 percentage units). During exercise, end-diastolic volume remained unchanged while end-systolic volume decreased by 19.4%, producing a 21.7% increase in stroke volume. Stroke volume ratios (left ventricular stroke volume counts/right ventricular stroke volume counts) approach unity (1.00 +/- 0.27). However, interobserver and intraobserver correlations are just fair, implying only a modest degree of accuracy and reliability of the procedure. This imprecision needs to be considered when evaluating the results of nuclear equilibrium right ventriculography.