Using Porous Media Theory to Determine the Coil Volume Needed to Arrest Flow in Brain Aneurysms - Porous Media: Applications in Biological Systems and Biotechnology - page 245

calculated the mechanical stresses in flexible walls of brain aneurysm assuming
same mechanical properties for both aneurysm and intracranial artery.
The ability to perform accurate aneurysm wall stress computations
depends significantly on the mechanical behavior of the aneurysm's wall. Our
future work will focus on developing a constitutive model for the aneurysm
wall capable of reflecting the actual experimental data over a wide range of
deformations in a physical model. The mechanical properties of the aneurysm
wall will be determined in a tensile testing machine using tissues obtained
from autopsy room. The proposed constitutive wall model fitted to mechani-
cal behavior of the brain aneurysms will be entered into the fluid-solid inter-
face model to represent the best approximation to the mechanics of the living
artery and aneurysm in a specific patient. We will develop a robust numer-
ical model of the wall stress distribution within brain aneurysms that can
assist in the clinical management of patients by predicting the risk of rupture
over time and permitting risk/benefit assessment for intervention or observa-
tion. Numerical simulations allow for the study of conditions that are dicult
or impossible to measure directly in humans or in animal models of brain
aneurysm.

6.10 Conclusions
A new model based on the porous media theory is proposed for the study
of the effects of coiling in brain aneurysms. In the absence of endovascular
coils, a wide-necked aneurysm was found to exhibit higher inflow velocity and
average pressure within the aneurysmal sac than a narrow-necked aneurysm.
The effect of the inserted platinum coil on the flow fields within an aneurysm
sac under pulsatile flow condition was studied numerically. We showed that
a 20% filling was sucient to stop blood flow into aneurysmal sac. Porous
media theory permits the study of fluid motion across small spaces of variable
and complex geometry.

6.11 References

[1] Nield, D. A. and Bejan, A. (1995). Convection in Porous Media. 2nd ed.,
Springer-Verlag, New York.

Vafai, K. (2000). Handbook of Porous Media. 1st ed., Marcel Dekker, Inc.,
New York.

[2] Vafai, K. (2005). Handbook of Porous Media. 2nd ed., Taylor & Francis
Group, New York.