Particulate Radiographic Contrast Material in Quantitative Evaluation of Experimental Mitral Insufficiency

Abstract

An experimental macroparticulate contrast material (contrast-impregnated gelatin spherules) proved to be a sensitive indicator of patterns of intracardiac blood flow. To evaluate its use in the quantitative assessment of mitral regurgitation, the following technique was developed: Transseptal catheterization of the left atrium of dogs with experimentally induced mitral insufficiency was followed by high-speed cinefluorography of the left heart during intra-atrial injection of the radiopaque particles. Slow projection of completed films allowed the enumeration of particles expelled from the left ventricle into the aorta and of particles regurgitating into the left atrium. If one assumes proportionality between the flux of counted particles and the corresponding blood flows, the determined degree of mitral regurgitation ranged from 35 to 73% of the total left ventricular output (with standard deviations of 3.3 to 12.2 for consecutive groups of 100 particles employed). Good correlation was obtained with the results of indicator-dilution studies, using double sampling and continuous infusion techniques.