Quantitative coronary angiography in the current era: principles and applications.

Coronary angiography, despite its inherent invasiveness and need for contrast media and radiographic exposure, is still routinely employed every year for the diagnostic and therapeutic management of millions of patients with or at risk for coronary artery disease. Whereas approximate visual estimation is the most common way to evaluate coronary angiography findings, since the late 1980s a number of investigators have developed and investigated methods of quantitative coronary angiography (QCA) analysis exploiting automated or semi-automated edge detection. Despite the inherent drawback of QCA due to its focus on the contrast-filled lumen of the vessel, QCA has offered and continues to offer important insights for clinical research and, in selected cases, clinical practice. This review aims thus to provide a comprehensive and updated viewpoint on the actual role of QCA.