Evaluation of the densitometric method of ejection fraction by direct digital subtraction left ventriculography.

The aim of the present study was to test the hypothesis that the densitometric ejection fraction (EF) could be calculated by direct contrast digital subtraction left ventriculography in a single heartbeat. Thirty patients underwent direct contrast digital subtraction left ventriculography and biplane conventional left ventriculography. The values of EF were obtained from digital subtraction ventriculograms of the first cardiac cycle after completion of the injection of the contrast medium by the videodensitometric technique and were compared with those obtained from conventional ventriculograms by the area-length method in the same patients. There was a close correlation between the densitometric EF from digital subtraction ventriculograms and the volumetric EF from conventional ventriculograms (r = 0.78). Densitometric EF measured in the 30 degree right anterior oblique projection highly correlated with densitometric EF measured in the 60 degree left anterior projection (r = 0.98). These data suggest that this densitometric technique is available in any projection and is a simple procedure for the accurate measurement of left ventricular EF.