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Contribution of the Hemodynamics of A1 Dysplasia or Hypoplasia to Anterior Communicating Artery Aneurysms: A 3-Dimensional Numerical Simulation Study

Xu, Liyan MD; Zhang, Fang MD; Wang, Haibao PhD; Yu, Yongqiang MD, PhD

Journal of Computer Assisted Tomography: July/August 2012 - Volume 36 - Issue 4 - p 421–426
doi: 10.1097/RCT.0b013e3182574dea

Objective To explore the association between the hemodynamics and formation, growth, and rupture of aneurysms in anterior communicating arteries (ACoA) with A1 dysplasia or hypoplasia.

Methods A series of 3-dimensional numerical simulation models of the anterior communicating artery complex (ACoAC) were designed geometrically. The diameter of A1 was fixed on one side and decreased gradually on the other side. Three groups of ACoA aneurysm model growth were constructed with different positions to the dominant bifurcation. Blood flow was modeled as an incompressible Newtonian fluid described by the unsteady Navier-Stokes equations. Vessel walls were assumed to be rigid; no slip boundary conditions were applied at the walls.

Results Wall shear stress (WSS), flow velocity, and pressure were influenced by the dynamic variations of A1 diameter. When the diameter of the nondominant A1 gradually decreased, WSS and flow velocity dynamically increased in the dominant bifurcation and pressure decreased. Wall shear stress differences were significant between the dominant and nondominant bifurcations (t = 6.543; P < 0.05). With aneurysm growth, WSS and flow velocity gradually decreased, and turbulence appeared. Wall shear stress was lower at the bifurcation than that 0.02 mm and 0.1 mm to the bifurcation, whereas flow velocity and turbulent flow were more obvious.

Conclusions A1 dysplasia/hypoplasia is a potential risk factor in the formation of ACoA aneurysms. Wall shear stress increase may contribute to aneurysm formation. Wall shear stress decrease and turbulent flow may be responsible for the growth and rupture of ACoA aneurysms. The hemodynamic mechanism in the growth and rupture of aneurysms in different locations might be different.

From the *Department of Radiology, the First Affiliated Hospital of Anhui Medical University, Hefei, China; and †Department of Radiology, the People’s Hospital of Huaibei, Anhui, P.R. China.

Received for publication February 2, 2012; accepted March 26, 2012.

Reprints: Yongqiang Yu, MD, PhD, Department of Radiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China (e-mail:

Liyan Xu and Fang Zhang contributed equally to this work.

This investigation was supported by grants from National Nature Science Foundation of China, grant number 30870712.

There are no conflicts of interest in this study.

Copyright © 2012 Wolters Kluwer Health, Inc. All rights reserved.