Accurate internal correction for the magnification of cineangiocardiography in infants with congenital heart disease

Correction for x-ray magnification at cineangiocardiography (cine) requires accurate localization of the level of the left ventricle (LV). This study compared LV volumes calculated using a standard external reference object (area grid) with volumes calculated using an intracardiac radiopaque catheter balloon in cine studies of casts (n = 26), normal lambs (n = 15), and infants with congenital heart disease (n = 11). Comparisons of LV volumes calculated using both correction methods with true cast displacement volumes were excellent (r = 0.99). Correlations of both methods were highly significant (p less than 0.001) in casts (r = 0.99), normal lambs (r = 0.97), and in infants (r = 0.83). The absolute percent difference (17.6 +/- 2.4 SE%) between LV volumes calculated by both methods was greatest in infants. Thus external localization of the LV may be more difficult in infants. The radiopaque balloon provides convenient accurate correction for cine x-ray magnification and calculation of LV volumes, particularly since flow-directed catheters are widely used for diagnostic cine ventriculography in infants.