Comparative in-vitro validation of eight first- and second-generation quantitative coronary angiography systems

Background It is known that first-generation quantitative coronary angiography (QCA) systems overestimate small vessel sizes owing to the point-spread function of the respective X-ray imaging chain, With second-generation systems new algorithms were introduced to correct for this source of error. Objective To evaluate the efficiency of the modified contour detection algorithms. Methods Six second-generation QCA systems (CMS, QANSAD, AWOS, CAAS II, Cardio 500, and Angioimage) were validated and compared with first-generation systems (CAAS and ARTREK). By using an arterial phantom consisting of stenotic and nonstenotic glass tubes (of diameters 0.5-5.0 mm) the accuracy and precision of each analysis system, as well as their additional accuracy and precision values for phantom diameters less than or equal to 1.0 mm were determined. Results All systems had high accuracy and precision values, but first-generation systems overestimated small vessel diameters. With second-generation systems a significantly improved accuracy in the submillimeter range (an accuracy within +/- 0.028 mm) was obtained, This improvement was accompanied by a moderate reduction in precision in the submillimeter range. Conclusion The new algorithms of the second-generation QCA systems allow accurate and reliable measurements of small coronary dimensions and, therefore, precise analysis of coronary stenoses of moderate-to-high grade seems feasible with the improved accuracy of the new systems.