[Evaluation of coronary arterial stenosis before and after PTCA: visual estimation versus computer-assisted analysis]

Coronary arteriogram of 34 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were evaluated visually and by computer-assisted analysis, that employed an edge detection method and cine-videodensitometry. The results of visual estimation were in general agreement with those of computer-assisted analysis for determination of percent area of stenosis in severe stenosis, and percent diameter of stenosis in slightly stenotic lesions. Before PTCA, the findings obtained by densitometry agreed with those using the edge detection method. However, after PTCA, the results were significantly different. This discrepancy may have been due to asymmetric morphologic changes in the luminal cross sectional area immediately after PTCA, which could not be assessed by the edge detection method in a single-plane view. Through these studies it was concluded that the densitometry is most useful for evaluating the effects of PTCA.