Project Description
Computational Biomechanics of Cerebral Aneurysms. The long-term goal of this research is to determine a
set of biomechanical parameters influencing rupture of cerebral aneurysms. We are developing fluid-structure interaction models for
the assessment of treatment options for these aneurysms. In this regard, we have evaluated local flow patterns, distributions of wall
pressure, wall shear stress, oscillatory shear index, and spatial and temporal gradients of wall shear stress at aneurysms of the
basilar and internal carotid arteries. This resulted in the analysis of the “inflow region” of an aneurysm, providing recommendations
as to how an endovascular device should be introduced through this region accounting for the local hemodynamics effects. In the near
future we will be performing ex vivo soft tissue mechanical testing of cerebral aneurysms to determine the mechanical properties of
tissue samples obtained from patients undergoing complex intracranial surgery and develop a constitutive framework characterizing
aneurysmal tissue. Our efforts on zero-pressure geometry estimation and in vivo image-based outflow conditions will be extended to
this project to obtain anatomically realistic models of the cerebral vasculature that can be used for the assessment of at-risk
aneurysms. In addition, we intend to develop a computational methodology for “virtual placement” of stents and divertors for the
endovascular repair of cerebral aneurysms. Our initial efforts in this area indicate the need for having a priori knowledge of the
optimal location of the stent to reduce blood flow at the inflow region of the aneurysm.
Patient-specific cerebral aneurysm model with virtual stent deployment within the basilar artery.
Computational Biomechanics of Abdominal Aortic Aneurysms. The long-term goal of this research is the
development of a computational tool for assessment of abdominal aortic aneurysm (AAA) rupture potential on an individual basis and its
implementation in a clinical setting. The optimal treatment strategy for AAAs is clear: prevention of rupture is the primary goal in
management of aneurysmal disease. We are interested in measuring the diseased arterial tissue deformation non-invasively and the in vivo physiological forces on the wall of patient-specific AAAs. We are investigating the central hypothesis that, once an AAA is
diagnosed, the primary biomechanical determinant of rupture potential is the non-uniform arterial wall thickness, within the context
of a dynamic assessment of aneurysm mechanics. The primary goal of this project is to address this hypothesis by predicting AAA risk
of rupture on a patient-specific basis for subjects that will undergo elective repair and retrospectively examining ruptured aneurysms.
The biomechanical environment of the native AAAs will be reproduced by non-invasively evaluating blood flow in the abdominal aorta,
aneurysmal wall thickness and wall motion as it is mediated by the cardiac cycle. Dynamic indicators of AAA risk of rupture to be
evaluated include peak wall stress, peak intra-aneurysmal sac pressure, and spatial and temporal changes in aneurysmal wall thickness.
Retrospectively evaluating these indicators for ruptured aneurysms will provide a threshold for which future diagnosed AAAs can be
measured against to assess their potential for mechanical failure in a clinical setting. These biomechanical and clinical endpoints
will be assessed using computational and imaging techniques (fluid-structure interaction modeling, cine-, phase-contrast and spin echo
MRI, CT imaging, ad hoc segmentation and reconstruction algorithms, particle image velocimetry, and soft tissue mechanics frameworks).
Static stress analysis of patient-specific AAA model.
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