Videodensitometric determination of minimum coronary artery luminal diameter before and after angioplasty.

Quantitative measurements of coronary stenoses were made from digital coronary angiograms in 19 patients before and after percutaneous transluminal coronary angioplasty (PTCA). Two methods of measurement were compared. Mean stenosis before PTCA was 67 +/- 10% by the edge detection method and 67 +/- 12% by videodensitometry (difference not significant). After PTCA, the mean stenosis was 32 +/- 14% by edge detection and 30 +/- 13% by videodensitometry (difference not significant). In addition, a new method was developed to rapidly calculate the absolute minimum luminal area and diameter by videodensitometry. The minimum luminal diameter before PTCA was 1.0 +/- 0.5 mm and after PTCA increased to 2.4 +/- 0.5 mm (p less than 0.001). The validity of the videodensitometric method was analyzed in a series of Lucite phantom studies, which suggested that when there is an irregular angiographic appearance, the densitometric method may be more accurate than standard edge detection methods. Digital acquisition of coronary angiograms provides a means for rapid application of quantitative analysis during coronary interventional procedures.