ADAPTIVE APPROACH TO ACCURATE ANALYSIS OF SMALL-DIAMETER VESSELS IN CINEANGIOGRAMS

In coronary vessels smaller than 1 mm in diameter, it is difficult to accurately identify lumen borders using existing border detection tech niques, Computer-detected diameters of small coronary vessels are ofte n severely overestimated due to the influence of the imaging system po int spread function and Computer-detected the use of an edge operator designed for a broad range of diameter vessel sizes, Computer-detected diameters may be corrected if a calibration curve for the X-ray syste m is available, Unfortunately, the performance of this postprocessing diameter correction approach is severely limited by the presence of im age noise, We report here a new approach that uses a two-stage adaptio n of edge operator parameters to optimally match the edge operator to the local lumen diameter, In the first stage, approximate lumen diamet ers are detected using a single edge operator in a half-resolution ima ge. Depending on the approximate lumen size, one of three edge operato rs is selected for the second full-resolution stage in which left and right coronary borders are simultaneously identified. The method was t ested in a set of 72 segments of nine angiographic phantom vessels wit h diameters ranging from 0.46 to 4.14 mm and in 82 clinical coronary a ngiograms, Performance of the adaptive simultaneous border detection m ethod was compared to that of a conventional border detection method a nd to that of a postprocessing diameter correction border detection me thod, Adaptive border detection yielded significantly improved accurac y in small phantom vessels and across all vessel sizes in comparison t o the conventional and postprocessing diameter correction methods (p < 0.001 in all cases), Adaptive simultaneous coronary border detection provides both accurate and robust quantitative analysis of coronary ve ssels of all sizes.