Hydrean, Christen McPhee
(2009)
Design and Development of a Novel Device for the Uniaxial Mechanical Analysis of Cerebral Artery Tissue.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
In order to further advance the research of cerebral aneurysms, the study of the mechanical and structural properties of the cerebral arterial wall has been undertaken. A device has been designed and built that is capable of performing controlled uniaxial loading tests on arterial ring segments. The ring segments are placed around two carbon steel half-circle pins and then stretched to desired strains using a slide micrometer and stepper motor. During testing, the sample is immersed in a cuvette of saline solution to imitate in-vivo conditions. The load is measured using a load cell attached to the micrometer and the system is automated using Labview software. Strain can be determined from recorded images of the displacement of markers on the tissue or more roughly approximated by the pin displacement. To validate the device, studies were performed on fresh and frozen bovine carotid arteries. Additionally, the device can be used to fix ring segments under prescribed loads or strain. In these applications, the tissue is loaded in the device and then fixed by filling the cuvette with paraformaldehyde solution. Upon removal from the solution, the internal elastic laminae (IEL) in the arterial segment is inspected and photographed under a confocal microscope to evaluate the fenestrae (natural holes) in the IEL as well as possible damage to the IEL. Past studies have revealed that elastin content and organization may be a key determinant in the intrinsic elastic properties of the arterial wall at low loads. The loss of the elastin membrane in cerebral arteries is a distinguishing feature of early stage aneurysm formation. The device was used for preliminary studies of the effect of high strain on the IEL of human cerebral arteries. Large tears parallel to the direction of the folds in the IEL and perpendicular to the loading direction were observed. We conjecture that this failure mode may be important in transluminal angioplasty of cerebral vessels.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
25 September 2009 |
| Date Type: |
Completion |
| Defense Date: |
18 June 2009 |
| Approval Date: |
25 September 2009 |
| Submission Date: |
20 July 2009 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MSME - Master of Science in Mechanical Engineering |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
arterial wall mechanics; cerebral aneurysm; cerebral arteries; Circle of Willis; confocal microscopy; uniaxial testing |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-07202009-000226/, etd-07202009-000226 |
| Date Deposited: |
10 Nov 2011 19:52 |
| Last Modified: |
19 Dec 2016 14:36 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8464 |
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