To improve diagnosis and understanding of the risk of rupture of atherosclerotic plaque, new strategies to realistically determine mechanical properties of atherosclerotic plaque need to be developed. In this study, an in vitro experimental method is proposed for accurate 3-D assessment of (diseased) vessel geometry using ultrasound. The method was applied to a vascular phantom, a healthy porcine carotid artery and human carotid endarterectomy specimens (n = 6). Vessel segments were pressure fixed and rotated in 10 ° steps. Longitudinal cross sections were imaged over 360 °. Findings were validated using micro-computed tomography (μCT). Results show good agreement between ultrasound and μCT-based geometries of the different segment types (I...