Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Technische Universitaet Graz, Faculty of Computer Science and Biomedical Engineering , Institute of Biomechanics, Avusturya
Tezin Onay Tarihi: 2020
Tezin Dili: İngilizce
Öğrenci: Eckmann Jakob David
Asıl Danışman (Eş Danışmanlı Tezler İçin): Gerhard A Holzapfel
Eş Danışman: Osman Gültekin
Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
Özet:
Atherosclerosis is one of the most common cardiovascular diseases and causes the devel-
opment of an atherosclerotic plaque. A rupture of an atherosclerotic plaque inhibits throm-
bus formation, which can be released into the blood stream and lead to further diseases,
such as a heart attack, a pulmonary embolism or a stroke. Therefore, the understanding
of atherosclerosis is vital in order to be able to assess the vulnerability of plaques, i.e. the
likelihood of the plaque to rupture. Physicians typically use geometrical parameters which
they can obtain from imaging procedures to define the vulnerability of plaques. However,
studies have shown that these geometrical parameters are not sufficient for the definition of
a vulnerable plaque. Hence, the understanding of the stress state and the rupture behavior
of atherosclerotic plaques has to be improved in order to find more sophisticated criteria
for the definition of critical plaque morphologies.
The present thesis investigates the influence of two distinct parameters, the lipid pool
amount and the fibrous cap thickness, on the development of a crack on nine different
plaque geometries. Such a crack might result in rupture and release of thrombogenic ma-
terial. Therefore, a parametrized geometry generation algorithm, where one can adjust the
aforementioned parameters, was developed. Additionally, the influence of an exponential
model on the numerical stability compared to a polynomial model achieved by a Taylor
series expansion is analyzed.
The simulations indicate that the vulnerability of plaques is increased with the increasing
lipid pool amount. Surprisingly, the fibrous cap thickness seems to have a decreasing
influence with increasing lipid pool amount. The simulations have shown that the position
and amount of calcification present within the plaque might have an influence on the crack
position. The analysis of a benchmark problem with the different material models has
shown that the polynomial model increases the stability of the simulations.
This thesis shows the influence of the lipid pool amount and the fibrous cap thickness.
However, future work focusing on the amount and the position of the calcification is needed
in order to achieve an even better understanding of atherosclerotic plaques.