Quantitative Coronary Angiography in Interventional Cardiology

Quantitative coronary angiography (QCA) has had a major impact in the field of interventional cardiology. Due to its superior accuracy objectivity and improved interobserver and intraobserver variability it has supplanted visual and hand-held caliper assessments of coronary arteriograms [1–3]. QCA is now the gold standard for assessing the coronary tree in the context of scientific research. It has not yet gained widespread appeal for routine clinical use because of expense and time constraints. To date there are two different techniques for measuring quantitative angiographic stenosis. One is based on the detection of luminal borders from orthogonal images to create a three-dimensional approximation of the diseased vessel, and the other uses videodensitometry of the stenosis to extract three-dimensional information from a single angiographic view. Although the latter approach has particular advantages, we favor the edge detection method because it provides absolute measurements that are relatively insensitive to the image quality.