Quantification of intracoronary volume by videodensitometry: validation study using fluid filling of human coronary casts.

Changes in intracoronary volume reflect the hemodynamic significance of progression or regression of diffuse coronary artery disease where intracoronary catheters cannot be applied for direct measurements due to small vessel dimensions. We have validated the videodensitometric measurement of intracoronary volume with epoxy casts of postmortem human coronary arteries. The volume of 31 coronary segments (cross-sectional areas in a range of 2-13 mm2) measured by fluid-filling using a precision dispenser was compared with the respective single plane intracoronary volume assessments obtained by the videodensitometric algorithm of the new generation Cardiovascular Angiography Analysis System (CAAS II). The true and measured values of volume were compared by calculation of the mean of the signed differences +/- standard deviation and by linear regression analysis. Videodensitometric measurement of intracoronary volume correlate well with fluid-filling of human coronary artery casts (correlation coefficient: r = 0.99, y = 1.96 +/- 0.99x, standard error of estimate: SEE = 3.96) with a significant trend towards overestimation of true volume values (mean difference = 1.73 +/- 3.64 mm3, P < 0.05). Intracoronary volume estimations can be used to measure changes of luminal dimensions of coronary arteries and may offer a new approach to assessment of progression or regression of diffuse coronary artery disease.