title: Effect of parent artery expansion by stent placement in cerebral aneurysms.
abstract: BACKGROUND
  Stent placement for cerebral aneurysms leads to a decrease in blood flow. This occurs not only through the direct obstruction of flow but also by the expansion of the parent artery. The latter has been observed in several clinical studies.
  
  
  OBJECTIVE
  The goal of this study was to clarify the effects of parent artery expansion after stent treatment on the following: 1) decrease in blood flow to an aneurysm, 2) wall shear stress (WSS), and 3) oscillatory shear index (OSI).
  
  
  METHODS
  The parent artery geometry constructed U-shape. The aneurysm location with respect to the U-shaped parent artery was determined according to previous clinical data. We performed calculations in unsteady-state situations using constructed models.
  
  
  RESULTS
  Parent artery expansion with stent reduces blood inflow to an aneurysm and WSS of the aneurysm wall, in addition to increasing OSI. The aneurysm position affects the decrease of the inflow rate and WSS ratio and increases the OSI ratio. Expansion causes the majority of effects on flow reduction inside an aneurysm model. Thus, the expansion effects of all samples should not be neglected.
  
  
  CONCLUSIONS
  These data suggest that parent artery expansion and its effect should be measured and included in the total decrease in blood flow. Parent artery expansion may induce intimal hyperplasia, thus increasing the thickness of the aneurysm wall.
authors.affiliation: Interfaculty Initiative in Information Studies, The University of Tokyo, Bunkyo-ku, Tokyo, Japan Earthquake Research Institute, The University of Tokyo, Tokyo, Japan.
authors.forename: Futoshi
authors.initials: F
authors.lastname: Mori
authors.affiliation: Kanazawa Institute of Technology, Kanazawa, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Hanida
authors.affiliation: Institute of Fluid Science, Tohoku University, Sendai, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohta
authors.affiliation: Research Center for Simulation Science, Japan Advanced Institute of Science and Technology, Ishikawa, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Matsuzawa
mesh_terms: D001158:Arteries / Q000503:physiopathology; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D057510:Endovascular Procedures / Q000379:methods; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D011859:Radiography; D015607:Stents
keywords: Parent artery; cerebral aneurysm; flow rate; intimal hyperplasia; oscillatory shear index; stent; wall shear stress