title: Sensitivity of patient-specific numerical simulation of cerebal aneurysm hemodynamics to inflow boundary conditions.
abstract: OBJECTIVE
  Due to the difficulty of obtaining patient-specific velocity measurements during imaging, many assumptions have to be made while imposing inflow boundary conditions in numerical simulations conducted using patient-specific, imaging-based cerebral aneurysm models. These assumptions can introduce errors, resulting in lack of agreement between the computed flow fields and the true blood flow in the patient. The purpose of this study is to evaluate the effect of the assumptions made while imposing inflow boundary conditions on aneurysmal hemodynamics.
  
  
  METHODS
  A patient-based anterior communicating artery aneurysm model was selected for this study. The effects of various inflow parameters on numerical simulations conducted using this model were then investigated by varying these parameters over ranges reported in the literature. Specifically, we investigated the effects of heart and blood flow rates as well as the distribution of flow rates in the A1 segments of the anterior cerebral artery. The simulations revealed that the shear stress distributions on the aneurysm surface were largely unaffected by changes in heart rate except at locations where the shear stress magnitudes were small. On the other hand, the shear stress distributions were found to be sensitive to the ratio of the flow rates in the feeding arteries as well as to variations in the blood flow rate.
  
  
  CONCLUSIONS
  Measurement of the blood flow rate as well as the distribution of the flow rates in the patient's feeding arteries may be needed for numerical simulations to accurately reproduce the intraaneurysmal hemodynamics in a specific aneurysm in the clinical setting.
authors.affiliation: Philips Medical Systems North America, Bothell, Washington, USA. prem.venugopal@gmail.com
authors.forename: Prem
authors.initials: P
authors.lastname: Venugopal
authors.forename: Daniel
authors.initials: D
authors.lastname: Valentino
authors.forename: Holger
authors.initials: H
authors.lastname: Schmitt
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Villablanca
authors.forename: Fernando
authors.initials: F
authors.lastname: Viñuela
authors.forename: Gary
authors.initials: G
authors.lastname: Duckwiler
mesh_terms: D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D020342:Finite Element Analysis; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000503:physiopathology*; D015233:Models, Statistical; D012212:Rheology; D014057:Tomography, X-Ray Computed