A majority of patients who suffer hemorrhaging as a result of a ruptured cerebral aneurysm experience reduced quality of life, long term brain damage, or death. Improved understanding of the flow patterns in cerebral aneurysms will lead to better techniques for their detection and treatment. Experiments are conducted in a generic flow phantom to characterize the basic behavior of blood flow in basilar saccular aneurysms. The test setup models a saccular aneurysm that forms at the bifurcation of the basilar artery into the Circle of Willis. Three input flow conditions are tested: a physiological flow waveform obtained from Kato (2002) [1] and two steady flow conditions corresponding to the peak and mean flow rates of the physiological flow waveform. Steady cases are examined to study the effect of increasing Reynolds number on the flow and the pulsatile case to quantify unsteady effects. The results reveal highly three dimensional flow patterns within the aneurysm. Velocity and vorticity fluctuations are extracted to investigate the nature of the unsteady flows. Wall shear stress is estimated around the aneurysm dome to examine its role in wall weakening and failure.

1.
Kato
T.
,
Indo
T.
,
Yoshida
E.
,
Iwasaki
Y.
,
Sone
M.
, and
Sobue
G.
,
2002
. “
Contrast-enhanced 2D Cine Phase MR Angiography for measurement of basilar artery blood flow in posterior circulation ischemia
.”
AJNR Am J Neuroradiol
,
23
(
6)
, Sept., pp.
530
542
.
2.
Raps
E. C.
,
Rogers
J. D.
,
Galetta
S. L.
,
Solomon
R. A.
,
Lennihan
L.
,
Klebanoff
L. M.
, and
Fink
M. E.
,
1993
. “
The clinical spectrum of unruptured intracranial aneurysms
.”
Arch Neurol.
,
50
(
3)
, Mar., pp.
265
268
.
3.
Weibers
D.
,
1998
. “
Unruptured intracranial aneurysms - risk of rupture and risks of surgical intervention
.”
N Engl J Med.
,
339
(
24)
, Dec., pp.
1725
33
.
4.
Fogelholm
R.
,
Hernesniemi
J.
, and
Vapalahti
M.
,
1993
. “
Impact of early surgery on outcome after aneurysmal subarachnoid hemorrhage. A population-based study
.”
Stroke
,
24
, Nov., pp.
1649
1654
.
5.
Inagawa
T.
,
Tokuda
Y.
,
Ohbayashi
N.
,
Takaya
M.
, and
Moritake
K.
,
1995
. “
Study of aneurysmal subarachnoid hemorrhage in Izumo City, Japan
.”
Stroke
,
26
(
5)
, May, pp.
761
766
.
6.
Longstretch
W. T.
,
Nelson
L. M.
,
Koepsell
T. D.
, and
vanBelle
G.
,
1993
. “
Clinical course of spontaneous subarachnoid hemorrhage: A population-based study in King County, Washington
.”
Neurology
,
43
(
4)
, Apr., pp.
712
718
.
7.
Sacco
R. L.
,
Wolf
P. A.
,
Bharuch
N. E.
,
Meeks
S. L.
,
Kannel
W. B.
,
Charette
L. J.
,
McNamara
P. M.
,
Palmer
E. P.
, and
D’Agostino
R.
,
1984
. “
Subarachnoid and intracerebral hemorrhage: Natural history, prognosis, and precursive factors in the Framingham study
.”
Neurology
,
34
(
7)
, July, pp.
847
54
.
8.
Schievink
W.
,
Wijdicks
E.
,
Parisi
J.
,
Piepgras
D.
, and
Whisnant
J.
,
1995
. “
Sudden death from aneurysmal subarachnoid hemorrhage
.”
Neurology
,
45
(
5)
, May, pp.
871
874
.
9.
American Heart Association, “Marfan syndrome.” Accessed: May 25, 2006 http://www.americanheart.org/presenter.jhtml?identifier=4672.
10.
Inci
S.
, and
Spetzler
R.
,
2000
. “
Intracranial aneurysms and arterial hypertension: A review and hypothesis
.”
Surg Neurol
,
53
(
6)
, June, pp.
530
542
.
11.
Fry
D.
,
1968
. “
Acute vascular endothelial changes associated with increased blood velocity gradients
.”
Circ Res
,
22
, Feb., pp.
165
197
.
12.
Kondo
S.
,
Hashimoto
N.
,
Kikuchi
H.
,
Hazama
F.
,
Nagata
I.
, and
Kataoka
H.
,
1997
. “
Cerebral aneurysms arising at nonbranching sites. An experimental study
.”
AJNR Am J Neuroradiol
,
28
(
2)
, Feb., pp.
398
403
.
13.
Shojima, M., Oshima, M., Takagi, K., Torii, R., Hayakawa, M., Katada, K., Morita, A., and Kirino, T., 2004. “Magnitude and role of wall shear stress on cerebral aneurysm. computational fluid dynamic study of 20 middle cerebral artery aneurysms.” Stroke, DOI: 10.1161/01.STR.0000144648.89172.of
14.
Malek
A. M.
,
Alper
S. L.
, and
Izumo
S.
,
1999
. “
Hemodynamic shear stress and its role in atherosclerosis
.”
JAMA
,
282
(
21)
, Dec., pp.
2035
2042
.
15.
Vega
C.
,
Kwoon
J.
, and
Lavine
S.
,
2002
. “
Intracranial aneurysms: Current evidence and clinical practice
.”
Am Fam Physician
,
66
(
7)
, Aug., pp.
601
608
.
16.
Ortega, J., Maitland, D., Wilson, T., Tsai, W., and Saloner, D., 2006. “Vascular dynamics of a shape memory polymer foam aneurysm treatment technique.” J Biomed Eng, In review.
17.
Womersley
J. R.
,
1995
. “
Method of calculation of velocity, rate of flow, and viscous drag in arteries when the pressure gradient is known
”.
J Physiology
,
128
, pp.
629
640
.
18.
Nguyen
T.
,
Biadillah
Y.
,
Mongrain
R.
,
Brunette
J.
,
Tardif
J.-C.
, and
Bertrand
O. F.
,
2004
. “
A method for matching the refractive index and kinematic viscosity of a blood analog for flow visualization in hydraulic cardiovascular models
.”
J Biomed Eng
,
126
(
4)
, Aug., pp.
529
535
.
19.
Tsuei
L.
, and
Savas¸
O¨.
,
2000
. “
Treatment of interfaces in particle image velocimetry
.”
Exp Fluids
,
29
(
3)
, Sept., pp.
203
214
.
This content is only available via PDF.
You do not currently have access to this content.