title: Determining the Presence of Thin-Walled Regions at High-Pressure Areas in Unruptured Cerebral Aneurysms by Using Computational Fluid Dynamics.
abstract: Thin-walled regions (TWRs) of cerebral aneurysms are at high risk of rupture, and careful attention should be paid during surgical procedures. Despite this, an optimal imaging technique to estimate TWRs has not been established. Previously, pressure elevation at TWRs was reported with computational fluid dynamics (CFD) but not fully evaluated.
  
  
  
  To investigate the possibility of predicting aneurysmal TWRs at high-pressure areas with CFD.
  
  
  
  Fifty unruptured middle cerebral artery aneurysms were analyzed. Spatial and temporal maximum pressure (Pmax) areas were determined with a fluid-flow formula under pulsatile blood flow conditions. Intraoperatively, TWRs of aneurysm domes were identified as reddish areas relative to the healthy normal middle cerebral arteries; 5 neurosurgeons evaluated and divided these regions according to Pmax area and TWR correspondence. Pressure difference (PD) was defined as the degree of pressure elevation on the aneurysmal wall at Pmax and was calculated by subtracting the average pressure from the Pmax and dividing by the dynamic pressure at the aneurysm inlet side for normalization.
  
  
  
  In 41 of the 50 cases (82.0%), the Pmax areas and TWRs corresponded. PD values were significantly higher in the correspondence group than in the noncorrespondence group (P = .008). A receiver-operating characteristic curve demonstrated that PD accurately predicted TWRs at Pmax areas (area under the curve, 0.764; 95% confidence interval, 0.574-0.955; cutoff value, 0.607; sensitivity, 66.7%; specificity, 82.9%).
  
  
  
  A high PD may be a key parameter for predicting TWRs in unruptured cerebral aneurysms.
  
  
  
  CFD, computational fluid dynamicsMCA, middle cerebral arteryPave, average pressurePD, pressure differencePmax, maximum pressureTWR, thin-walled regionWSS, wall shear stress.
authors.affiliation: *Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan; ‡Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan; §Graduate School of Mechanical Engineering and ¶Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takao
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Kambayashi
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Watanabe
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Issei
authors.initials: I
authors.lastname: Kan
authors.forename: Kengo
authors.initials: K
authors.lastname: Nishimura
authors.forename: Shogo
authors.initials: S
authors.lastname: Kaku
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ishibashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ikeuchi
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Fujii
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murayama
mesh_terms: D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012306:Risk; D013314:Stress, Mechanical