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Subject Specific Wall Shear Stress in the Human Thoracic Aorta
Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
Linköping University, Department of Medicine and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology.ORCID iD: 0000-0001-5526-2399
2006 (English)In: WSEAS Transaction on biology and biomedicine, ISSN 1109-9518, Vol. 10, no 3, 609-614 p.Article in journal (Refereed) Published
Abstract [en]

Numerous studies have shown a correlation between Wall Shear Stress (WSS) and atherosclerosis, but few have evaluated the reliability of estimation methods and measures used to assessWSS, which is the subject of this work. A subject specific vessel model of the aortic arch and thoracic aorta is created fromMRI images and used for CFD simulations with MRI velocity measurements as inlet boundary condition. WSS is computed from the simulation results. Aortic WSS shows significant spatial as well as temporal variation during a cardiac cycle, which makes circumferential values very uninformative, and approximate estimates using Hagen-Poiseuille fails predict the averageWSS. Highly asymmetric flow, especially in the arch, causes the spatial WSS variations.

Place, publisher, year, edition, pages
2006. Vol. 10, no 3, 609-614 p.
Keyword [en]
Wall shear stress, CFD, Aorta, Circumferential average values, Asymmetric flow
National Category
Engineering and Technology
URN: urn:nbn:se:liu:diva-43727Local ID: 74619OAI: diva2:264587
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2016-03-14Bibliographically approved
In thesis
1. Towards Subject Specific Aortic Wall Shear Stress: a combined CFD and MRI approach
Open this publication in new window or tab >>Towards Subject Specific Aortic Wall Shear Stress: a combined CFD and MRI approach
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The cardiovascular system is an important part of the human body since it transports both energy and oxygen to all cells throughout the body. Diseases in this system are often dangerous and cardiovascular diseases are the number one killer in the western world. Common cardiovascular diseases are heart attack and stroke, which origins from obstructed blood flow. It is generally important to understand the causes for these cardiovascular diseases. The main causes for these diseases are atherosclerosis development in the arteries (hardening and abnormal growth). This transform of the arterial wall is believed to be influenced by the mechanical load from the flowing blood on the artery and especially the tangential force the wall shear stress. To retrieve wall shear stress information in arteries invivo is highly interesting due to the coupling to atherosclerosis and indeed a challenge. The goal of this thesis is to develop, describe and evaluate an in-vivo method for subject specific wall shear stress estimations in the human aorta, the largest artery in the human body. The method uses an image based computational fluid dynamics approach in order to estimate the wall shear stress. To retrieve in-vivo geometrical descriptions of the aorta magnetic resonance imaging capabilities is used which creates image material describing the subject specific geometry of the aorta. Magnetic resonance imaging is also used to retrieve subject specific blood velocity information in the aorta. Both aortic geometry and velocity is gained at the same time. Thereafter the image material is interpreted using level-set segmentation in order to get a three-dimensional description of the aorta. Computational fluid dynamics simulations is applied on the subject specific aorta in order to calculate time resolved wall shear stress distribution at the entire aortic wall included in the actual model.

This work shows that it is possible to estimate subject specific wall shear stress in the human aorta. The results from a group of healthy volunteers revealed that the arterial geometry is very subject specific and the different wall shear stress distributions have general similarities but the level and local distribution are clearly different. Sensitivity (on wall shear stress) to image modality, the different segmentation methods and different inlet velocity profiles have been tested, which resulted in these general conclusions:

  • The aortic diameter from magnetic resonance imaging became similar to the reference diameter measurement method.
  • The fast semi-automatic level-set segmentation method gave similar geometry and wall shear stress results when compared to a reference segmentation method.
  • Wall shear stress distribution became different when comparing a simplified uniform velocity profile inlet boundary condition with a measured velocity profile.

The method proposed in this thesis has the possibility to produce subject specific wall shear stress distribution in the human aorta. The method can be used for further medical research regarding atherosclerosis development and has the possibility for usage in clinical work.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2011. 40 p.
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1360
National Category
Fluid Mechanics and Acoustics
urn:nbn:se:liu:diva-65910 (URN)978-91-7393-244-8 (ISBN)
Public defence
2011-04-12, ACAS, hus A, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Available from: 2011-02-25 Created: 2011-02-25 Last updated: 2016-03-14Bibliographically approved

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Gårdhagen, RolandRenner, JohanLänne, TosteKarlsson, Matts
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Applied Thermodynamics and Fluid MechanicsThe Institute of TechnologyPhysiologyFaculty of Health SciencesDepartment of Thoracic and Vascular SurgeryBiomedical Modelling and Simulation
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