Single-vessel quantitative coronary angiography (QCA) software is inaccurate when used in bifurcation lesions due to the specific anatomical characteristics of bifurcations, including the natural step-down in diameters after every bifurcation. Dedicated bifurcation QCA software has been developed to overcome the limitations of single-vessel QCA in bifurcations. A phantom validation study has shown the superior accuracy of these bifurcation QCA algorithms compared to the single-vessel QCA software. These QCA software algorithms are currently highly recommended to assess bifurcation lesions.