Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime.

Takanobu Yagi, Ayaka Sato, Manabu Shinke, Sara Takahashi, Yasutaka Tobe, Hiroyuki Takao, Yuichi Murayama, Mitsuo Umezu

Research output: Contribution to journalArticle

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Abstract

This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.

Original languageEnglish
Pages (from-to)20121031
Number of pages1
JournalJournal of the Royal Society, Interface / the Royal Society
Volume10
Issue number82
DOIs
Publication statusPublished - 2013 May 6

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Rheology
Intracranial Aneurysm
Velocity measurement
Reynolds number
Shear stress
Silicone Elastomers
Cerebral Arteries
Diastole
Systole
Hemodynamics
Hydrodynamics
Flow visualization
Laminar flow
Silicones
Aneurysm
Rupture
Rubber
Heart Rate
Degradation
Geometry

ASJC Scopus subject areas

  • Medicine(all)

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Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry : transition from a laminar regime. / Yagi, Takanobu; Sato, Ayaka; Shinke, Manabu; Takahashi, Sara; Tobe, Yasutaka; Takao, Hiroyuki; Murayama, Yuichi; Umezu, Mitsuo.

In: Journal of the Royal Society, Interface / the Royal Society, Vol. 10, No. 82, 06.05.2013, p. 20121031.

Research output: Contribution to journalArticle

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