title: Stagnation and complex flow in ruptured cerebral aneurysms: a possible association with hemostatic pattern.
abstract: OBJECT Histopathological examination has revealed that ruptured cerebral aneurysms have different hemostatic patterns depending on the location of the clot formation. In this study, the authors investigated whether the hemostatic patterns had specific hemodynamic features using computational fluid dynamics (CFD) analysis. METHODS Twenty-six ruptured middle cerebral artery aneurysms were evaluated by 3D CT angiography and harvested at the time of clipping. The hemostatic patterns at the rupture points were assessed by means of histopathological examination, and morphological parameters were obtained. Transient analysis was performed, and wall shear stress-related hemodynamic parameters and invariant Q (vortex core region) were calculated. The morphological and hemodynamic parameters were compared among the hemostatic patterns. RESULTS Hematoxylin and eosin staining of the aneurysm wall showed 13 inside-pattern, 9 outside-pattern, and 4 other-pattern aneurysms. Three of the 26 aneurysms were excluded from further analysis, because their geometry models could not be generated due to low vascular CT values. Mann-Whitney U-tests showed that lower dome volume (0.04 cm3vs 0.12 cm3, p = 0.014), gradient oscillatory number (0.0234 vs 0.0289, p = 0.023), invariant Q (-0.801 10-2/sec2vs -0.124 10-2/sec2, p = 0.045) and higher aneurysm formation indicator (0.986 vs 0.963, p = 0.041) were significantly related to inside-pattern aneurysms when compared with outside-pattern aneurysms. CONCLUSIONS Inside-pattern aneurysms may have simpler flow patterns and less flow stagnation than outside-pattern aneurysms. CFD may be useful to characterize the hemostatic pattern of ruptured cerebral aneurysms.
authors.affiliation: Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Mie.
authors.forename: Masanori
authors.initials: M
authors.lastname: Tsuji
authors.affiliation: Department of Neurological Surgery, Research Institute for Brain and Blood Vessels, Akita, Akita.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Neurosurgery, Mie Chuo Medical Center, National Hospital Organization, Tsu, Mie; and.
authors.forename: Fujimaro
authors.initials: F
authors.lastname: Ishida
authors.affiliation: Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Mie.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Furukawa
authors.affiliation: Department of Neurosurgery, Suzuka Kaisei Hospital, Suzuka, Mie, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Miura
authors.affiliation: Department of Neurosurgery, Mie Chuo Medical Center, National Hospital Organization, Tsu, Mie; and.
authors.forename: Masato
authors.initials: M
authors.lastname: Shiba
authors.affiliation: Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Mie.
authors.forename: Takanori
authors.initials: T
authors.lastname: Sano
authors.affiliation: Department of Neurosurgery, Mie Chuo Medical Center, National Hospital Organization, Tsu, Mie; and.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanemura
authors.affiliation: Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Mie.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Umeda
authors.affiliation: Department of Neurosurgery, Mie Chuo Medical Center, National Hospital Organization, Tsu, Mie; and.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Shimosaka
authors.affiliation: Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Mie.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology; D012189:Retrospective Studies
keywords: ACA = anterior cerebral artery; AFI = aneurysm formation indicator; CFD = computational fluid dynamics; GON = gradient oscillatory number; ICA = internal cerebral artery; MCA = middle cerebral artery; OSI = oscillatory shear index; RIBBVA = Research Institute for Brain and Blood Vessels–Akita; STL = stereolithography; WSS = wall shear stress; WSSG = WSS gradient; computational fluid dynamics; hemostatic mechanism; histopathological examination; ruptured aneurysm; vascular disorders