Modeling the Interaction of Coils With the Local Blood Flow After Coil Embolization of Intracranial Aneurysms

[+] Author and Article Information
Kyung Se Cha

Department of Mechanical Engineering, University of Maryland, College Park, MD 20742

Elias Balaras1

Department of Mechanical Engineering, University of Maryland, College Park, MD 20742

Baruch B. Lieber, Chander Sadasivan

Department of Biomedical Engineering, and Department of Radiology, University of Miami, Miami, FL 33146

Ajay K. Wakhloo

Department of Radiology, Neurosurgery, and Neurology, University of Massachusetts Medical School, Worcester, MA 01655


Corresponding author.

J Biomech Eng 129(6), 873-879 (Apr 23, 2007) (7 pages) doi:10.1115/1.2800773 History: Received July 30, 2006; Revised April 23, 2007

Aneurysmal recanalization and coil compaction after coil embolization of intracranial aneurysms are seen in as many as 40% of cases. Higher packing density has been suggested to reduce both coil compaction and recanalization. Basilar bifurcation aneurysms remain a challenge due possibly to the hemodynamics of this specific aneurysm/parent vessel architecture, which subjects the coil mass at the aneurysm neck to elevated and repetitive impingement forces. In the present study, we propose a new modeling strategy that facilitates a better understanding of the complex interactions between detachable coils and the local blood flow. In particular, a semiheuristic porous media set of equations used to describe the intra-aneurysmal flow is coupled to the incompressible Navier–Stokes equations governing the dynamics of the flow in the involved vessels. The resulting system of equations is solved in a strongly coupled manner using a finite element formulation. Our results suggest that there is a complex interaction between the local hemodynamics and intra-aneurysmal flow that induces significant forces on the coil mass. Although higher packing densities have previously been advocated to reduce coil compaction, our simulations suggest that lower permeability of the coil mass at a given packing density could also promote faster intra-aneurysmal thrombosis due to increased residence times.

Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

(a) Schematic of a terminal aneurysm and the surrounding vessels. Dn and Dp are the diameters of the aneurysm neck and parent vessel, respectively, and the shaded area denotes the coil(s). (b) Zoom in of the shaded area in Part (a). A schematic of the pore structure after coil embolization is shown. l is the averaging length and d is the characteristic length scale at the pore level.

Grahic Jump Location
Figure 2

Three-dimensional geometry in the vicinity of the aneurysm. The flow rate variation imposed at the inflow plane is also shown.

Grahic Jump Location
Figure 3

Instantaneous velocity contours and velocity vectors near peak flow rate t∕T=0.2. Velocity is normalized with the average bulk velocity ⟨Ub⟩.

Grahic Jump Location
Figure 4

Instantaneous velocity contours and velocity vectors near the minimum flow rate t∕T=0.5. Velocity is normalized with the average bulk velocity ⟨Ub⟩.

Grahic Jump Location
Figure 5

Instantaneous streamlines near the peak flow rate t∕T=0.2. (a) Case 5; (b) Case 4.

Grahic Jump Location
Figure 6

Velocity profiles at an (y-z) plane at x=0 near the peak flow rate (t∕T=0.2) for three different grids (Cases 1, 2, and 3 in Table 1). (a) Location at the neck of the aneurysms; (b) location in the middle of the sac.

Grahic Jump Location
Figure 7

Temporal variation of (a) average pressure in the aneurysm normalized with the peak pressure from Case 4; (b) Flow rate into the aneurysm normalized with the average flow rate into the aneurysm from Case 4. (—) Case 5 (ϵ=0.7,Da=10−3); (----) Case 2 (ϵ=0.7,Da=10−4).

Grahic Jump Location
Figure 8

Variation of the hemodynamic force on the coil during the pulsatile cycle. (----) Case 5 (Dn∕Dp=1.0,ϵ=0.7,Da=10−3); (—) Case 2 (Dn∕Dp=1.0,ϵ=0.7,Da=10−4); (–∙–∙) Case 7, (Dn∕Dp=0.5,ϵ=0.7,Da=10−4).



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In