[Accuracy and performance of Roentgen-Videodensitometry for valvular regurgitation and ventricular ejection...

The accuracy of Roentgen-Videodensitometry is tested with respect to clinical applications of valvular insufficiency measurements as well as the determination of ventricular ejection fraction. For this purpose, criteria of data analysis were applied to densitometric measurements in order to provide a comparable degree of accuracy in patient studies as obtained by experimental investigations using electromagnetic flow measurements as well ventricular volume determination for comparison. 10 pigs with experimental aortic valve incompetence were studied for the analysis of 99 contrast dilution curves of the left ventricle: Accurate measurements of valvular regurgitation were obtained if the magnitude of contrast medium induced density changes was at least twice of non-specific density variations of the curves. Correlation of the according regurgitant fraction values with electromagnetic flowmeter data yielded r = 0.94, s = +/- 7.2% RGF (n = 90). Non-ideal washout of contrast medium from the ventricle was found not to be a limiting factor in these measurements. Calculation of ventricular ejection fraction by videodensitometry (n = 60) was in agreement with ventriculometry data only in half of the cases (r = 0.75, s = +/- 8.2% EF, n = 31); namely, if scattering of densitometric data of the washout part of the curves did not exceed a certain value (s = +/- 10% of highest value). This indicates the necessity of optimal indicator mixing as well as the limitations for the densitometric determination of this specific parameter.