| Coronary atherosclerosis is among the leading causes of death in western countries. Numerous studies have indicated that local vessel wall mechanics and fluid dynamics may be involved in atherogenesis. In view of the fact that human coronary arteries experience substantial motion during the cardiac cycle, and that this motion modulates both local wall mechanics and fluid dynamics, we have hypothesized that certain arterial motion patterns may play an important role in the pathogenesis of coronary atherosclerosis by generating an atherogenic mechanical environment. Hence, the objectives of this study are to develop the capability to quantitatively characterize the in vivo motion dynamics of coronary arteries, and to explore its biomechanical implications in coronary atherosclerosis.; Clinical biplane cineangiograms containing sequences of coronary artery images are used for this study. Calibration and dewarping are carried out using a calibration cube and dewarping plate. The frame-to-frame arterial motion is tracked by using a template matching technique. Time interpolation is performed to generate paired 2-D vessel axes. 3-D vessel axes are reconstructed, from which motion dynamic parameters of interest are derived.; The validations with a coronary arterial phantom and synthetic images show that the system can accurately track the non-uniform arterial motion, faithfully reconstruct a 3-D vessel axis from a pair of vessel projection images and reliably obtain in vivo measurements of arterial geometric parameters.; The system has been employed to quantify the in vivo motion dynamics of twelve human coronary arteries, including four right coronary arteries (RCA) and eight left anterior descending (LAD) coronary arteries. Motion dynamic parameters, including displacement, strain, curvature and torsion measurements have been characterized for both RCA and LAD. The results show that: (1) motion dynamic parameters of both LAD and RCA vary considerably with individuals and along the axial length; (2) in comparison with the LAD, the RCA has higher mean total displacement (p = 0.01), but lower mean average torsion (p = 0.03) and lower mean total twisting (p = 0.09); (3) there are no significant differences in motion dynamic parameters between normal and diseased LAD (α = 0.10); (4) in comparison with normal regions of diseased LAD, diseased regions have higher mean average torsion (p = 0.05). |
