Angiographic volume estimation of right ventricle. Re-evaluation of the previous methods.

Previous angiographic methods for volume estimation of the right ventricle were re-evaluated by ten cast studies as far as the positions of the right ventricular casts were concerned. The spatial orientation of the right ventricular chamber cavity varies clockwise or counterclockwise, in the normal heart. For right ventricular volume estimation, it is important to analyze the right ventricular casts with rotated positions. The casts were studied by biplane cineangiocardiograms with four clockwise rotated positions, which were 0 degrees, 30 degrees, 40 degrees, 45 degrees, and 60 degrees. Simpson's rule and the area-length methods were used for angiocardiographic determination of the right ventricular volume. In four positions, four linear regression equations comparing true volumes with calculated volumes had similar values to each other in the two methods. Regression equation comparing true volumes with calculated volumes which contained a total of 40 casts in four positions, yielded a high correlation coefficient (r = +0.98, p less than 0.001) and small errors in both Simpson's rule and the area-length methods. This study indicates that the right ventricular chamber volume can be accurately estimated with only one regression equation from biplane cineangiocardiograms, even when the right ventricular cavity would have been rotated clockwise or counterclockwise.