title: Hemodynamics in growing and stable cerebral aneurysms.
abstract: OBJECTIVE
  The detailed mechanisms of cerebral aneurysm evolution are poorly understood but are important for objective aneurysm evaluation and improved patient management. The purpose of this study was to identify hemodynamic conditions that may predispose aneurysms to growth.
  
  
  METHODS
  A total of 33 intracranial unruptured aneurysms longitudinally followed with three-dimensional imaging were studied. Patient-specific computational fluid dynamics models were constructed and used to quantitatively characterize the hemodynamic environments of these aneurysms. Hemodynamic characteristics of growing (n=16) and stable (n=17) aneurysms were compared. Logistic regression statistical models were constructed to test the predictability of aneurysm growth by hemodynamic features.
  
  
  RESULTS
  Growing aneurysms had significantly smaller shear rate ratios (p=0.01), higher concentration of wall shear stress (p=0.03), smaller vorticity ratios (p=0.01), and smaller viscous dissipation ratios (p=0.01) than stable aneurysms. They also tended to have larger areas under low wall shear stress (p=0.06) and larger aspect ratios (p=0.18), but these trends were not significant. Mean wall shear stress was not significantly different between growing and stable aneurysms. Logistic regression models based on hemodynamic variables were able to discriminate between growing and stable aneurysms with a high degree of accuracy (94-100%).
  
  
  CONCLUSIONS
  Growing aneurysms tend to have complex intrasaccular flow patterns that induce non-uniform wall shear stress distributions with areas of concentrated high wall shear stress and large areas of low wall shear stress. Statistical models based on hemodynamic features seem capable of discriminating between growing and stable aneurysms.
authors: Center for Computational Fluid Dynamics, College of Sciences, George Mason University, Fairfax, Virginia, USA.
authors: Daniel M
authors: DM
authors: Sforza
authors: Department of Neurosurgery, Wakayama Rosai Hospital, Wakayama, Japan.
authors: Kenichi
authors: K
authors: Kono
authors: Department of Interventional Neuroradiology, University of California Los Angeles Medical Center, Los Angeles, California, USA.
authors: Satoshi
authors: S
authors: Tateshima
authors: Department of Interventional Neuroradiology, University of California Los Angeles Medical Center, Los Angeles, California, USA.
authors: Fernando
authors: F
authors: Viñuela
authors: Department of Interventional Neuroradiology, Texas Neurointerventional Surgery Associates, Dallas, Texas, USA.
authors: Christopher
authors: C
authors: Putman
authors: Center for Computational Fluid Dynamics, College of Sciences, George Mason University, Fairfax, Virginia, USA.
authors: Juan R
authors: JR
authors: Cebral
mesh_terms: D000072226:Computed Tomography Angiography / Q000639:trends*; D018450:Disease Progression; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008137:Longitudinal Studies; D033081:Shear Strength / Q000502:physiology
keywords: Aneurysms; Computational Fluid Dynamics; Hemodynamics