Quantification of coronary arterial plaque volume using 3D reconstructions formed by fusing intravascular ultrasound and biplane angiography

This paper, through plaque quantification, demonstrates the use of three-dimensional (3D) reconstructions of coronary arteries to assess compensatory enlargement. The lumen and medial-adventitial border are segmented from intravascular ultrasound (IVUS) images using a novel 3D method called active surfaces and the segmented data is used to calculate the cross-sectional area of the lumen and vessel, respectively. The area of plaque for each slice is the difference of the two. Information about the distance between path points, located using a calibrated biplane angiography system, is used for the calculation of plaque volume. This quantification system can be used to track the progression or regression of atherosclerosis and is currently being used to document compensatory enlargement, a physiological phenomenon in which the overall vessel cross-sectional area increases with an increase in plaque area with little or no decrease in luminal cross-sectional area. Four ex-vivo cases have been quantified, all demonstrating this remodelling mechanism, shown by strong positive correlation between plaque area and vessel area over the reconstructed length of the vessel (R=0.98, R=0.93, R=0.98, R=0.68).