The Prospective Study on the macro-microscopic intra-aneurysmal flow causing the rupture

• Project/Area Number: 15360101
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Fluid engineering
• Research Institution: Keio University
• Principal Investigator: TANISHITA Kazuo Keio University, Faculty of Science and Technology, Professor, 理工学部, 教授 (10101776)
• Co-Investigator(Kenkyū-buntansha): OBI Shinnosuke Keio Univ., Faculty of Science and Technology, Associate Professor, 理工学部, 教授 (80233609) ; FUJIMOTO Keiji Keio Univ., Faculty of Science and Technology, Associate Professor, 理工学部, 助教授 (70229045) ; IKEDA Mariko Keio University, Professor Emeritus, 名誉教授 (00051368) ; KUDO Susumu Shibaura Institute of Technology, Assistant Professor, 工学部, 講師 (70306926)
• Project Period (FY): 2003 – 2004
• Project Status: Completed (Fiscal Year 2004)
• Budget Amount: ¥14,700,000 (Direct Cost: ¥14,700,000); Fiscal Year 2004: ¥5,500,000 (Direct Cost: ¥5,500,000); Fiscal Year 2003: ¥9,200,000 (Direct Cost: ¥9,200,000)
• Keywords: Biomechanics / Cerebral aneurysm / Prospective study / Realistic model / Fluid mechanics / Risk factor / Vessel structure / CT画像 / LDV / PIV / 血行力学

Research Abstract

Cerebral aneurysms have a variety of complicated shapes, and it greatly influences on blood flow structure. However, it is almost impossible to measure directly in vivo blood flow in detail. Instead, model experiment would be more appropriate to evaluate the detailed flow structure. In our present study, we built anatomically realistic models of cerebral aneurysm, measured detailed flow structure, and discussed the influence of geometric features and blood flow structure of cerebral aneurysms on the rupture.
We built realistic cerebral aneurysm models by photoforming method based on computed tomography images. The flow waveform in the parent arteries was completely simulated to the physiological pulsatile flow in cerebral arteries by setting Reynolds number and frequency parameter. We measured velocity profiles with particle image velocimetry and laser Doppler velocimeter.
Intra-aneurysmal flow was classified into two patterns. One consists of single circulating flow along the wall, and the other consists of circulating flow and low-velocity recirculating flow in bleb. Ruptured cerebral aneurysm model had the latter flow pattern. Furthermore, wall shear stress had a peak of 5.1 Pa in the ruptured cerebral aneurysms model, which was the highest in the employed models. The recirculating flow and high wall shear stress in bleb seem to be associated with the rupture of cerebral aneurysms, and that was influenced mainly by aspect ratio of aneurysm and neck-parent artery area ratio as a geometric parameter.
We also compared the distribution of WSS and the extent of degeneration of arterial wall tissues and suggested that low wall shear stress seen in the local portion of the bifurcation contributed to the degenerative changes followed by formation of cerebral aneurysms.

Research Products

• [Journal Article] Variation of Wall Shear Stress and Periodic Oscillations Induced in Right-Angle Branch During Laminar Steady Flow (2005)
  • Author(s): Tanishita, K et al.
  • Journal Title: Trans.ASME, J Fluid Engineering (in press)
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] ラット誘発脳動脈瘤内の流れの瘤発生への寄与 (2005)
  • Author(s): 谷下一夫 他
  • Journal Title: 第17回バイオエンジニアリング講演会講演論文集 04-48 Pages: 395-396
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Frontiers of bio-fluid mechanics and mass transfer in the arterial system (2005)
  • Author(s): Tanishita, K, Ohmura, H, Ueda, A, Kudo, S, Tateshima, S, Ikeda, M
  • Journal Title: Proc. 6^<th> World Congress on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics Pages: 18-19
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Shear dependent albumin uptake in cultured endothelial cells (2005)
  • Author(s): Tanishita, K, Shimomura, M, Ueda, A, Ikeda, M, Kudo, S
  • Journal Title: Biomechanics at micro-and nanoscale levels(ed, Wada, H)(World Scientific) vol.I Pages: 26-41
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Intra-aneurysmal flow visualization by phase contrast magnetic resonance in aging : feasibility in vitro study using a geometrically-realistic aneurysm model (2004)
  • Author(s): Tanishita, K et al.
  • Journal Title: J Neurosurg 100 Pages: 1041-1048
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] 脳動脈瘤発生における血管壁組織構造の変化と血流との関係 (2004)
  • Author(s): 谷下一夫 他
  • Journal Title: 日本バイオレオロジー学会誌増刊号 18 Pages: 31-31
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Intra-aneurysmal flow visualization by phase contrast magnetic resonance imaging: feasibility in vitro study using a geometrically-realistic aneurysm model (2004)
  • Author(s): Tateshima S, Grinstead J, Sinha S, Nien Y, Murayama Y, Villablanca JP, Tanishita K, Vinuela F.
  • Journal Title: J Neurosurg. 100(6) Pages: 1041-1048
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Intra-aneurysmal flow visualization by phase contrast MRI : feasibility study using a geometrically realistic in vitro aneurysm model (2004)
  • Author(s): Tateshima, S, Grinstead, J, Sinha, S, Nien Y, Murayama, Y, Villablanca, JP, Tanishita, K, Vinuela, F
  • Journal Title: Proc. Asian Pacific Conference on Biomechanics(JSME) Pages: 29-30
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Biomechanical analysis of flow structure in cerebral aneurysms based on the vorticity (2004)
  • Author(s): Omura, H, Morino, T, Tanishita, K, Tateshima, S, Murayama, Y, Vinuela, F
  • Journal Title: Proc. Asian Pacific Conference on Biomechanics(JSME) Pages: 31-32
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Relationship between microtubule network structure and intracellular transport in cultured endothelial cells affected by shear stress (2004)
  • Author(s): Kudo, S, Ikezawa, K, Ikeda, M, Tanishita, K
  • Journal Title: JSME Int J, Ser. C 47(4) Pages: 977-984
  • NAID: 110004820826
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Intra-aneurysmal flow visualization by phase contrast magnetic resonance imaging : feasibility in vitro study using a geometrically-realistic aneurysm model (2004)
  • Author(s): Tanishita, K et al.
  • Journal Title: J Neurosurg 100 Pages: 1041-1048
• [Journal Article] Variation of Wall Shear Stress and Periodic Oscillations Induced in Right-Angle Branch During Laminar Steady Flow
  • Author(s): Yamaguchi, R, Mashima, T, Amagai, H, Fujii, H, Hayase, T, Tanishita, K
  • Journal Title: Trans. ASME Journal of Fluid Engineering (in press)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Tanishita, K, Tateshima, S, et al.: "Three-dimensional blood flow analysis in a wide-necked internal carotid artery-ophthalmic artery aneurysm"J Neurosurg. 99. 526-533 (2003)
• [Publications] Tanishita, K, Tateshima, S, et al.: "Intra-aneurysmal Flow Visualization by Phase Contrast MRI : Feasibility Study Using a Geometrically Realistic in Vitro Aneurysm Model."Proc.First Asian Pacific Conference on Biomechanics. 29-30 (2004)
• [Publications] Tanishita, K, Tateshima, S, et al.: "Biomechanical analysis of flow structure in cerebral aneurysms"Proc.First Asian Pacific Conference on Biomechanics. 31-32 (2004)
• [Publications] 谷下一夫, 立嶋智 他: "脳動脈瘤破裂に関与する血流構造の解析"第16回バイオエンジニアリング講演会、講演論文集. 183-184 (2004)