The hemodynamics of cerebral aneurysms has been heavily investigated in recent years.
Computer simulations show a high influence of blood flow,
pressure and stress distribution on the growth and rupture of aneurysms [1-6].
The role of the vessel tissue,
on the other hand,
is still mostly unknown.
Very few measured data is available for intracranial aneurysm walls,
but in order to calculate the displacement and stress distribution in the vessel wall,
its physical properties (thickness,...
Methods and Materials
We use our own proprietary software MEDVIS 3D to perform computer simulations on patient-specific aneurysm geometries obtained through standard medical imaging procedures.
The numerical simulation is based on the finite element method (FEM),
which requires the generation of a computational mesh of tetrahedal elements from the segmented blood lumen.
The boundaries of the mesh are given by the vessel surface defined by an intensity threshold of the image data,
and a set of chosen cross sections...
We use the blood mesh shown in Fig. 2 and perform coupled fluid-structure simulations with different wall meshes,
applying the same boundary conditions in each case.
Physical properties of the blood needed for the flow simulation are well-known and can be found e.
in . We look at the resulting wall displacement and von Mises stress at peak systolic pressure (ca.
see Fig. 5 ).
we assume a basic thickness of 0.5 mm and an elastic modulus E of 2.7 MPa,
as it was used in...
Since physical measurement data of (living) cerebral aneurysm tissue is extremely hard to come by,
computer simulations provide a convenient opportunity to gain some insight into its behavior. We observe that a variation of the thickness changes the stress distribution in the wall considerably.
Our calculations show that stress peaks in the wall shift from the neck to the top of the aneurysm if the thickness of the aneurysm wall with respect to the afferent vessel is decreased.
Kirino T. Magnitude and role of wall shear stress on cerebral aneurysm: computational fluid dynamic study of 20 middle cerebral artery aneurysms.
2004;35:2500–2505 Cebral JR,
Putman CM. Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models.
AJNR Am J Neuroradiol.