University of Twente Student Theses


Dynamic geometry and plaque development in the coronary arteries

Zandwijk, J.K. van (2014) Dynamic geometry and plaque development in the coronary arteries.

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Abstract:Development of atherosclerotic plaques in the coronary arteries is reported to be influenced and enhanced by hemodynamic deviating situations. Coronary hemodynamics could in turn be influenced by static and dynamic geometry of the coronary arteries. These relationships could be used as identifiers to determine coronary artery disease risk profiles. However, the evidence in this area is mainly based on invasive techniques such as intravascular ultrasound and therefore sparse, and not suitable to be applied in a screening environment or in asymptomatic patients. Goals: To establish a method for quantifying coronary geometry characteristics in both static and dynamic situations, and to demonstrate relationships between coronary geometrical parameters and plaque development in the coronary arteries by using non-invasive imaging with computed tomography (CT). Methods: All patients in this study underwent coronary CT angiography with high-resolution reconstructions in one phase (patient Group 1) or low-resolution reconstructions in multi-phases (patient Group 2) of the cardiac cycle. Group 1 involved patients with extra-cardial arterial disease, and Group 2 patients scheduled for elective coronary angiography. Three-dimensional reconstructions of centerlines through the major coronary arteries were obtained using commercially available software. End-diastolic phases, respectively end-diastolic and end-systolic phases were used in quantification of static (Group 1) and dynamic (Group 2) geometrical parameters. These parameters included vessel length, curvature, tortuosity, and the number of inflection points. Plaque development was assessed as degree of stenosis, plaque type and length, and the cross-sectional distribution of plaque. Associations between geometry and plaque development were statistically investigated. Results: Static geometrical parameters showed an association with plaque development (patient Group 1, n=73). Dynamic geometrical parameters in patient Group 2 (n=71) could quantify changing geometry on artery and segment level in terms of curvature, tortuosity, and inflection points. No associations were found in patient Group 2 between change in geometry through the cardiac cycle and degree of stenosis. Both static and dynamic geometrical parameters were associated with length of plaque on segment level in patient Group 2. Plaques were preferably distributed close to the myocardium and in the inner curve of segments. Conclusion: Static parameters of the coronary arteries are associated with degree of stenosis in the coronary arteries, but this association was not found for change in geometry through the cardiac cycle. However, based on the results of both patient groups, it can be concluded that the relation of static and dynamic geometrical parameters with plaque length in segments can be an indication of the extent of coronary artery disease. New and deeper insights in anatomy, motion, and deformation of the coronary artery tree were obtained, which could eventually lead to development of novel image biomarkers to identify risk of coronary artery disease.
Item Type:Essay (Master)
UMC Groningen, Nederland
Faculty:TNW: Science and Technology
Subject:44 medicine, 50 technical science in general
Programme:Technical Medicine MSc (60033)
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