Timing and size of flow impingement in a giant intracranial aneurysm at the internal carotid artery


Flow impingement is regarded as a key factor for aneurysm formation and rupture. Wall shear stress (WSS) is often used to evaluate flow impingement even though WSS and impinging force are in two different directions; therefore, this raises an important question of whether using WSS for evaluation of flow impingement size is appropriate. Flow impinging behavior in a patient-specific model of a giant aneurysm (GA) at the internal carotid artery (ICA) was analyzed by computational fluid dynamics simulations. An Impingement Index (IMI) was used to evaluate the timing and size of flow impingement. In theory, the IMI is related to the WSS gradient, which is known to affect vascular biology of endothelial cells. Effect of non-Newtonian fluid, aneurysm size, and heart rate were also studied. Maximum WSS is found to be proportional to the IMI, but the area of high wall shear is not proportional to the size of impingement. A faster heart rate or larger aneurysm does not produce a larger impinging site, and the Newtonian assumption overestimates the size of impingement. Flow impingement at the dome occurs approximately 0.11 s after the peak of flow waveform is attained. This time delay also increases with aneurysm size and varies with heart rate and waveform.

This is a preview of subscription content, log in to check access.

Access options

Buy single article

Instant unlimited access to the full article PDF.

US$ 39.95

Price includes VAT for USA

Subscribe to journal

Immediate online access to all issues from 2019. Subscription will auto renew annually.

US$ 199

This is the net price. Taxes to be calculated in checkout.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9


  1. 1.

    Antiga L, Piccinelli M, Botti L, Ene-Iordache B, Remuzzi A, Steinman DA (2008) An image-based modeling framework for patient-specific computational hemodynamics. Med Biol Eng Comput 46:1097–1112

  2. 2.

    Boussel L, Rayz V, McCulloch C et al (2008) Aneurysm growth occurs at region of low wall shear stress: patient-specific correlation of hemodynamics and growth in a longitudinal study. Stroke 39:2997–3002

  3. 3.

    Buchanan JR Jr, Kleinstreuer C (1998) Simulation of particle-hemodynamics in a partially occluded artery segment with implications to the initiation of microemboli and secondary stenoses. J Biomech Eng 120:446–454

  4. 4.

    Buchanan JR, Kleinstreuer C, Hyun S, Truskey GA (2003) Hemodynamics simulation and identification of susceptible sites of atherosclerotic lesion formation in a model abdominal aorta. J Biomech 36:1185–1196

  5. 5.

    Burleson AC, Strother CM, Turitto VT (1995) Computer modeling of intracranial saccular and lateral aneurysms for the study of their hemodynamics. Neurosurgery 37:774–782 (discussion 774–782)

  6. 6.

    Casson M (1959) A flow equation for pigment-oil suspension of the printing ink type. In: Mills CC (ed) Rheology of disperse systems. Pergamon, Oxford, pp 84–104

  7. 7.

    Cebral JR, Castro MA, Burgess JE, Pergolizzi RS, Sheridan MJ, Putman CM (2005) Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models. AJNR Am J Neuroradiol 26:2550–2559

  8. 8.

    Chan KY, Fujioka H, Hirshl RB, Bartlett RH, Grotberg JB (2007) Pulsatile blood flow and gas exchange across a cylindrical fiber array. J Biomech Eng 129:676–687

  9. 9.

    Chien S (2008) Effects of disturbed flow on endothelial cells. Ann Biomed Eng 36:554–562

  10. 10.

    Chien A, Tateshima S, Castro M, Sayre J, Cebral J, Vinuela F (2008) Patient-specific flow analysis of brain aneurysms at a single location: comparison of hemodynamic characteristics in small aneurysms. Med Biol Eng Comput 46:1113–1120

  11. 11.

    Chien A, Tateshima S, Sayre J, Castro M, Cebral J, Vinuela F (2009) Patient-specific hemodynamic analysis of small internal carotid artery–ophthalmic artery aneurysms. Surg Neurol 72(5):444–450

  12. 12.

    Crawford T (1959) Some observations on the pathogenesis and natural history of intracranial aneurysms. J Neurol Neurosurg Psychiatry 22:259–266

  13. 13.

    Cziesla T, Biswas G, Chattopadhyay H, Mitra NK (2001) Large eddy simulation of flow and heat transfer in an impinging slot jet. Int J Heat Fluid Flow 22:500–558

  14. 14.

    Davies PF (2009) Hemodynamic shear stress and the endothelium in cardiovascular pathophysiology. Nat Clin Pract Cardiovasc Med 6:16–26

  15. 15.

    Ford MD, Alperin N, Lee SH, Holdsworth DW, Steinman DA (2005) Characterization of volumetric flow rate waveforms in the normal internal carotid and vertebral arteries. Physiol Meas 26:477–488

  16. 16.

    Foutrakis GN, Yonas H, Sclabassi RJ (1999) Saccular aneurysm formation in curved and bifurcating arteries. AJNR Am J Neuroradiol 20:1309–1317

  17. 17.

    Fung Y-C (1993) Biomechanics, mechanical properties of living tissues, 2nd edn. Springer-Verlag, New York, p 568

  18. 18.

    Glantz SA (2002) Primer of biostatistics. McGraw Hill, New York, p 489

  19. 19.

    Glor FP, Ariff B, Hughes AD et al (2004) The integration of medical imaging and computational fluid dynamics for measuring wall shear stress in carotid arteries. Conf Proc IEEE Eng Med Biol Soc 2:1415–1418

  20. 20.

    Hoi Y, Meng H, Woodward SH et al (2004) Effects of arterial geometry on aneurysm growth: three-dimensional computational fluid dynamics study. J Neurosurg 101:676–681

  21. 21.

    Huo Y, Choy JS, Svendsen M, Sinha AK, Kassab GS (2009) Effects of vessel compliance on flow pattern in porcine epicardial right coronary arterial tree. J Biomech 42:594–602

  22. 22.

    ISUIA-Investigators (1998) Unruptured intracranial aneurysms: risks of rupture and risks of surgical intervention. N Engl J Med 339:1725–1733

  23. 23.

    ISUIA-Investigators (2003) Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet 362:103–110

  24. 24.

    Jou LD, Lee DH, Morsi H, Mawad ME (2008) Wall shear stress on ruptured and unruptured intracranial aneurysms at the internal carotid artery. AJNR Am J Neuroradiol 29:1761–1767

  25. 25.

    Lee SW, Antiga L, Steinman DA (2009) Correlations among indicators of disturbed flow at the normal carotid bifurcation. J Biomech Eng 131:061013

  26. 26.

    Lei M, Kleinstreuer C, Truskey GA (1995) Numerical investigation and prediction of atherogenic sites in branching arteries. J Biomech Eng 117:350–357

  27. 27.

    Lieber B, Gounis M (2002) The physics of endoluminal stenting in the treatment of cerebrovascular aneurysms. Neurol Res 24:S33–S42

  28. 28.

    Marshall I, Papathanasopoulou P, Wartolowska K (2004) Carotid flow rates and flow division at the bifurcation in healthy volunteers. Physiol Meas 25:691–697

  29. 29.

    Meng H, Wang Z, Kim M, Ecker RD, Hopkins LN (2006) Saccular aneurysms on straight and curved vessels are subject to different hemodynamics: implications of intravascular stenting. AJNR Am J Neuroradiol 27:1861–1865

  30. 30.

    Neofytou P (2004) Comparison of blood rheological models for physiological flow simulation. Biorheology 41:693–714

  31. 31.

    Nichols WW, O’Rourke MF (2005) McDonald’s blood flow in arteries, 5th edn. Oxford University Press, Oxford, p 616

  32. 32.

    O’Rourke MF (2009) Time domain analysis of the arterial pulse in clinical medicine. Med Biol Eng Comput 47:119–129

  33. 33.

    O’Rourke MF, Hashimoto J (2007) Mechanical factors in arterial aging: a clinical perspective. J Am Coll Cardiol 50:1–13

  34. 34.

    Phares DJ, Smedley GT, Flagan RC (2000) The wall shear produced by the normal impingement of a jet on a flat surface. J Fluid Mech 418:351–375

  35. 35.

    Shimogonya Y, Ishikawa T, Imai Y, Matsuki N, Yamaguchi T (2009) Can temporal fluctuation in spatial wall shear stress gradient initiate a cerebral aneurysm? A proposed novel hemodynamic index, the gradient oscillatory number (GON). J Biomech 42:550–554

  36. 36.

    Siauw WL, Ng EY, Mazumdar J (2000) Unsteady stenosis flow prediction: a comparative study of non-Newtonian models with operator splitting scheme. Med Eng Phys 22:265–277

  37. 37.

    Soulis JV, Giannoglou GD, Chatzizisis YS, Seralidou KV, Parcharidis GE, Louridas GE (2008) Non-Newtonian models for molecular viscosity and wall shear stress in a 3D reconstructed human left coronary artery. Med Eng Phys 30:9–19

  38. 38.

    Steinman DA, Milner JS, Norley CJ, Lownie SP, Holdsworth DW (2003) Image-based computational simulation of flow dynamics in a giant intracranial aneurysm. AJNR Am J Neuroradiol 24:559–566

  39. 39.

    Szymanski MP, Metaxa E, Meng H, Kolega J (2008) Endothelial cell layer subjected to impinging flow mimicking the apex of an arterial bifurcation. Ann Biomed Eng 36:1681–1689

  40. 40.

    Tardy Y, Resnick N, Nagel T, Gimbrone MA Jr, Dewey CF Jr (1997) Shear stress gradients remodel endothelial monolayers in vitro via a cell proliferation-migration-loss cycle. Arterioscler Thromb Vasc Biol 17:3102–3106

  41. 41.

    Tremmel M, Dhar S, Levy EI, Mocco J, Meng H (2009) Influence of intracranial aneurysm-to-parent vessel size ratio on hemodynamics and implication for rupture: results from a virtual experimental study. Neurosurgery 64:622–630 (discussion 621–630)

  42. 42.

    Valencia AA, Guzman AM, Finol EA, Amon CH (2006) Blood flow dynamics in saccular aneurysm models of the basilar artery. J Biomech Eng 128:516–526

  43. 43.

    Valencia A, Morales H, Rivera R, Bravo E, Galvez M (2008) Blood flow dynamics in patient-specific cerebral aneurysm models: the relationship between wall shear stress and aneurysm area index. Med Eng Phys 30:329–340

  44. 44.

    Wang Z, Kolega J, Hoi Y et al (2009) Molecular alterations associated with aneurysmal remodeling are localized in the high hemodynamic stress region of a created carotid bifurcation. Neurosurgery 65:169–177 (discussion 168–177)

Download references

Conflict of interests

The authors declare that they have no conflict of interests.

Author information

Correspondence to Liang-Der Jou.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1. Simulation of velocity contour during a cardiac cycle (MPG 518 kb)

Supplementary material 1. Simulation of velocity contour during a cardiac cycle (MPG 518 kb)

Supplementary material 2. Fluoroscopy of the giant aneurysm at 7.5 frames/s (MPG 1064 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Jou, L., Mawad, M.E. Timing and size of flow impingement in a giant intracranial aneurysm at the internal carotid artery. Med Biol Eng Comput 49, 891–899 (2011).

Download citation


  • Aneurysm
  • Intracranial aneurysm
  • Blood flow