title: Distinctive flow pattern of wall shear stress and oscillatory shear index: similarity and dissimilarity in ruptured and unruptured cerebral aneurysm blebs.
abstract: OBJECTIVE
  The difference in the hemodynamics of wall shear stress (WSS) and oscillatory shear index (OSI) between ruptured and unruptured aneurysms is not well understood. The authors investigated the hemodynamic similarities and dissimilarities in ruptured and thin-walled unruptured aneurysm blebs.
  
  
  METHODS
  Magnetic resonance imaging-based fluid dynamics analysis was used to calculate WSS and OSI, and hemodynamic and intraoperative findings were compared. The authors also compared ruptured and unruptured thin-walled blebs for the magnitude of WSS and OSI.
  
  
  RESULTS
  Intraoperatively, 13 ruptured and 139 thin-walled unruptured aneurysm blebs were identified. Twelve of the ruptured (92.3%) and 124 of the unruptured blebs (89.2%) manifested low WSS and high OSI. The degree of WSS was significantly lower in ruptured (0.49 ± 0.12 Pa) than in unruptured (0.64 ± 0.15 Pa; p < 0.01) blebs.
  
  
  CONCLUSIONS
  Ruptured and unruptured blebs shared a distinctive pattern of low WSS and high OSI. The degree of WSS at the rupture site was significantly lower than in the unruptured thin-walled blebs.
authors.affiliation: Departments of Neurosurgery, Aomori Prefectural Central Hospital, Aomori, Japan. kawaguchi@nsg.med.tohoku.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Shinjitsu
authors.initials: S
authors.lastname: Nishimura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanamori
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takazawa
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Omodaka
authors.forename: Kenya
authors.initials: K
authors.lastname: Sato
authors.forename: Noriko
authors.initials: N
authors.lastname: Maeda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Midorikawa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sasaki
authors.forename: Michiharu
authors.initials: M
authors.lastname: Nishijima
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002533:Cerebral Angiography; D015331:Cohort Studies; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D012039:Regional Blood Flow / Q000502:physiology*; D012189:Retrospective Studies; D013314:Stress, Mechanical