Quantitative analysis of coronary dynamics by time-dependent ultrasound imaging

Intravascular ultrasound imaging is a new technique that displays information on lumen and arterial walls, and is capable of providing real-time monitoring of cross-sectional high- resolution images. This technique has potential application for studying the dynamics of the arterial wall with respect to the presence or absence of pathology and the vascular response to physiological or pharmacological stimuli. Although the extraction of information related to coronary dynamics and wall pathologies is possible by manual procedures it is very time consuming and influenced by intra- and interobserver errors. We developed an evaluation system for analyzing 3D spaces defined by digitized cross-sectional ultrasound images of coronaries quantifying the vasomotion in relation to the morphology of the arterial wall. Sequences of echographic images were obtained and recorded as ordered stacks of 2D frames on a VHS videotape. For each image, an automatic lumen edge segmentation was performed, then 3D reconstruction was obtained to evaluate time-dependent lumen and vessel wall changes. These 3D representations serve to demonstrate dynamic phenomena and to perform quantitative analyses (e.g., area/hemidiameter variations, projections, sections, 'carving,' etc.).