Sang, Chao
(2021)
Failure of Cerebral Aneurysms and Arterial Tissues.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
A cerebral aneurysm (CA) is most commonly a saccular enlargement in the wall of a cerebral artery. Aneurysm rupture is associated with high morbidity and mortality and hence there is a pressing need to better understand the disease progression and rupture mechanisms. Clinically useful metrics for assessment of rupture risk can be identified based on this information.
Accurate measurements of mechanical properties of arterial tissues is essential for rupture risk assessment and development of more realistic mathematical models. Although uniaxial tensile testing is commonly used to evaluate failure properties of vascular tissue, there is no established protocol for specimen shape or gripping method. We developed a new uniaxial testing approach that can achieve consistent failure in the mid-region of small specimens, even for vessels from older individuals and small cerebral aneurysm tissues and used this approach to analyze the failure process in human cerebral and sheep carotid arteries.
Collagen is the major passive load bearing component in arteries including cerebral artery and aneurysmal walls. To maintain a sustainable level of intramural loads and avoid rupture, the collagen fabric must adapt in response to the temporally evolving cerebral aneurysm geometry. To study the remodeling of collagen structure during disease progression as well as its role in failure of arterial tissue, 22 elastase-induced rabbit aneurysms were studied using multiphoton microscope (MPM) imaging and mechanical testing. The results were also compared to human aneurysm data.
Inclusions such as calcification can affect the stress distribution and strength of arterial walls. The role of calcification in failure of cerebral arterial tissues remains unknown. The high prevalence of calcification in cerebral aneurysms has been shown previously. To better understand the role of calcification in cerebral arterial tissues, the prevalence of calcification in cerebral arteries was investigated. A methodology was developed and preliminary data obtained to analyze the interaction between collagen fibers and calcification during mechanical loading.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
26 January 2021 |
| Date Type: |
Publication |
| Defense Date: |
18 September 2020 |
| Approval Date: |
26 January 2021 |
| Submission Date: |
7 October 2020 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
157 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
cerebral aneurysms, cerebral arteries, failure mechanism, collagen remodeling, vascular calcification |
| Date Deposited: |
26 Jan 2021 16:38 |
| Last Modified: |
26 Jan 2022 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/39777 |
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