Background. Computational fluid dynamics (CFD) simulations using medical-image-based anatomical vascular geometry are now gaining clinical relevance. This study aimed at validating the CFD methodology for studying cerebral aneurysms by using particle image velocimetry (PIV) measurements, with a focus on the effects of small geometric variations in aneurysm models on the flow dynamics obtained with CFD. Method of Approach. An experimental phantom was fabricated out of silicone elastomer to best mimic a spherical aneurysm model. PIV measurements were obtained from the phantom and compared with the CFD results from an ideal spherical aneurysm model (S1). These measurements were also compared with CFD results, based on the geometry reconstructed from three-dimensional images of the experimental phantom. We further performed CFD analysis on two geometric variations, S2 and S3, of the phantom to investigate the effects of small geometric variations on the aneurysmal flow field. Results. We found poor agreement between the CFD results from the ideal spherical aneurysm model and the PIV measurements from the phantom, including inconsistent secondary flow patterns. The CFD results based on the actual phantom geometry, however, matched well with the PIV measurements. CFD of models S2 and S3 produced qualitatively similar flow fields to that of the phantom but quantitatively significant changes in key hemodynamic parameters such as vorticity, positive circulation, and wall shear stress. Conclusion. CFD simulation results can closely match experimental measurements as long as both are performed on the same model geometry. Small geometric variations on the aneurysm model can significantly alter the flow-field and key hemodynamic parameters. Since medical images are subjected to geometric uncertainties, image-based patient-specific CFD results must be carefully scrutinized before providing clinical feedback.

1.
Ku
,
D. N.
, 1997, “
Blood Flow in Arteries
,”
Annu. Rev. Fluid Mech.
0066-4189,
29
, pp.
399
434
.
2.
Burleson
,
A. C.
, and
Turitto
,
V. T.
, 1996, “
Identification of Quantifiable Hemodynamic Factors in the Assessment of Cerebral Aneurysm Behavior. On Behalf of the Subcommittee on Biorheology of the Scientific and Standardization Committee of the ISTH
,”
Thromb. Haemostasis
0340-6245,
76
(
1
), pp.
118
123
.
3.
Gibson
,
C. M.
,
Diaz
,
L.
,
Kandarpa
,
K.
,
Sacks
,
F. M.
,
Pasternak
,
R. C.
,
Sandor
,
T.
,
Feldman
,
C.
, and
Stone
,
P. H.
, 1993, “
Relation of Vessel Wall Shear Stress to Atherosclerosis Progression in Human Coronary Arteries
,”
Arterioscler. Thromb.
1049-8834,
13
(
2
), pp.
310
315
.
4.
Malek
,
A. M.
,
Alper
,
S. L.
, and
Izumo
,
S.
, 1999, “
Hemodynamic Shear Stress and Its Role in Atherosclerosis
,”
JAMA, J. Am. Med. Assoc.
0098-7484,
282
(
21
), pp.
2035
2042
.
5.
Cebral
,
J. R.
,
Yim
,
P. J.
,
Lohner
,
R.
,
Soto
,
O.
, and
Choyke
,
P. L.
, 2002, “
Blood Flow Modeling in Carotid Arteries With Computational Fluid Dynamics and MR Imaging
,”
Acad. Radiol.
1076-6332,
9
(
11
), pp.
1286
1299
.
6.
Cebral
,
J. R.
,
Castro
,
M. A.
,
Appanaboyina
,
S.
,
Putman
,
C. M.
,
Millan
,
D.
, and
Frangi
,
A. F.
, 2005, “
Efficient Pipeline for Image-Based Patient-Specific Analysis of Cerebral Aneurysm Hemodynamics: Technique and Sensitivity
,”
IEEE Trans. Med. Imaging
0278-0062,
24
(
4
), pp.
457
467
.
7.
Jou
,
L. D.
,
Quick
,
C. M.
,
Young
,
W. L.
,
Lawton
,
M. T.
,
Higashida
,
R.
,
Martin
,
A.
, and
Saloner
,
D.
, 2003, “
Computational Approach to Quantifying Hemodynamic Forces in Giant Cerebral Aneurysms
,”
AJNR Am. J. Neuroradiol.
0195-6108,
24
(
9
), pp.
1804
1810
.
8.
Glor
,
F. P.
,
Long
,
Q.
,
Hughes
,
A. D.
,
Augst
,
A. D.
,
Ariff
,
B.
,
Thom
,
S. A.
,
Verdonck
,
P. R.
, and
Xu
,
X. Y.
, 2003, “
Reproducibility Study of Magnetic Resonance Image-Based Computational Fluid Dynamics Prediction of Carotid Bifurcation Flow
,”
Ann. Biomed. Eng.
0090-6964,
31
(
2
), pp.
142
151
.
9.
Glor
,
F. P.
,
Ariff
,
B.
,
Hughes
,
A. D.
,
Verdonck
,
P. R.
,
Thom
,
S. A.
,
Barratt
,
D. C.
, and
Xu
,
X. Y.
, 2005, “
Operator Dependence of 3-D Ultrasound-Based Computational Fluid Dynamics for the Carotid Bifurcation
,”
IEEE Trans. Med. Imaging
0278-0062,
24
(
4
), pp.
451
456
.
10.
Steinman
,
D. A.
,
Thomas
,
J. B.
,
Ladak
,
H. M.
,
Milner
,
J. S.
,
Rutt
,
B. K.
, and
Spence
,
J. D.
, 2002, “
Reconstruction of Carotid Bifurcation Hemodynamics and Wall Thickness Using Computational Fluid Dynamics and MRI
,”
Magn. Reson. Med.
0740-3194,
47
(
1
), pp.
149
159
.
11.
Steinman
,
D. A.
,
Milner
,
J. S.
,
Norley
,
C. J.
,
Lownie
,
S. P.
, and
Holdsworth
,
D. W.
, 2003, “
Image-Based Computational Simulation of Flow Dynamics in a Giant Intracranial Aneurysm
,”
AJNR Am. J. Neuroradiol.
0195-6108,
24
(
4
), pp.
559
566
.
12.
Steinman
,
D. A.
,
Vorp
,
D. A.
, and
Ethier
,
C. R.
, 2003, “
Computational Modeling of Arterial Biomechanics: Insights Into Pathogenesis and Treatment of Vascular Disease
,”
J. Vasc. Surg.
0741-5214,
37
(
5
), pp.
1118
1128
.
13.
Hassan
,
T.
,
Timofeev
,
E. V.
,
Saito
,
T.
,
Shimizu
,
H.
,
Ezura
,
M.
,
Tominaga
,
T.
,
Takahashi
,
A.
, and
Takayama
,
K.
, 2004, “
Computational Replicas: Anatomic Reconstructions of Cerebral Vessels as Volume Numerical Grids at Three-Dimensional Angiography
,”
AJNR Am. J. Neuroradiol.
0195-6108,
25
(
8
), pp.
1356
1365
.
14.
Thomas
,
J. B.
,
Milner
,
J. S.
,
Rutt
,
B. K.
, and
Steinman
,
D. A.
, 2003, “
Reproducibility of Image-Based Computational Fluid Dynamics Models of the Human Carotid Bifurcation
,”
Ann. Biomed. Eng.
0090-6964,
31
(
2
), pp.
132
141
.
15.
Ernemann
,
U. U.
,
Gronewaller
,
E.
,
Duffner
,
F. B.
,
Guervit
,
O.
,
Claassen
,
J.
, and
Skalej
,
M. D.
, 2003, “
Influence of Geometric and Hemodynamic Parameters on Aneurysm Visualization During Three-Dimensional Rotational Angiography: an in vitro Study
,”
AJNR Am. J. Neuroradiol.
0195-6108,
24
(
4
), pp.
597
603
.
16.
Moore
,
J. A.
,
Steinman
,
D. A.
, and
Ethier
,
C. R.
, 1998, “
Computational Blood Flow Modelling: Errors Associated With Reconstructing Finite Element Models From Magnetic Resonance Images
,”
J. Biomech.
0021-9290,
31
(
2
), pp.
179
184
.
17.
Augst
,
A. D.
,
Barratt
,
D. C.
,
Hughes
,
A. D.
,
Glor
,
F. P.
,
Mc
,
G. T. S. A.
, and
Xu
,
X. Y.
, 2003, “
Accuracy and Reproducibility of CFD Predicted Wall Shear Stress Using 3D Ultrasound Images
,”
ASME J. Biomech. Eng.
0148-0731,
125
(
2
), pp.
218
222
.
18.
Glor
,
F. P.
,
Westenberg
,
J. J.
,
Vierendeels
,
J.
,
Danilouchkine
,
M.
, and
Verdonck
,
P.
, 2002, “
Validation of the Coupling of Magnetic Resonance Imaging Velocity Measurements With Computational Fluid Dynamics in a U Bend
,”
Artif. Organs
0160-564X,
26
(
7
), pp.
622
635
.
19.
Oshima
,
M.
,
Sakai
,
H.
, and
Torii
,
R.
, 2005, “
Modelling of Inflow Boundary Conditions for Image-Based Simulation of Cerebrovascular Flow
,”
Int. J. Numer. Methods Fluids
0271-2091,
47
(
6–7
), pp.
603
617
.
20.
Moore
,
J. A.
,
Rutt
,
B. K.
,
Karlik
,
S. J.
,
Yin
,
K.
, and
Ethier
,
C. R.
, 1999, “
Computational Blood Flow Modeling Based on in vivo Measurements
,”
Ann. Biomed. Eng.
0090-6964,
27
(
5
), pp.
627
640
.
21.
Moore
,
J. A.
,
Steinman
,
D. A.
,
Holdsworth
,
D. W.
, and
Ethier
,
C. R.
, 1999, “
Accuracy of Computational Hemodynamics in Complex Arterial Geometries Reconstructed From Magnetic Resonance Imaging
,”
Ann. Biomed. Eng.
0090-6964,
27
(
1
), pp.
32
41
.
22.
Moore
,
J. A.
,
Steinman
,
D. A.
,
Prakash
,
S.
,
Johnston
,
K. W.
, and
Ethier
,
C. R.
, 1999, “
A Numerical Study of Blood Flow Patterns in Anatomically Realistic and Simplified End-to-Side Anastomoses
,”
ASME J. Biomech. Eng.
0148-0731,
121
(
3
), pp.
265
272
.
23.
Imbesi
,
S. G.
, and
Kerber
,
C. W.
, 2001, “
Analysis of Slipstream Flow in a Wide-Necked Basilar Artery Aneurysm: Evaluation of Potential Treatment Regimens
,”
AJNR Am. J. Neuroradiol.
0195-6108,
22
(
4
), pp.
721
724
.
24.
Rhee
,
K.
,
Han
,
M. H.
, and
Cha
,
S. H.
, 2002, “
Changes of Flow Characteristics by Stenting in Aneurysm Models: Influence of Aneurysm Geometry and Stent Porosity
,”
Ann. Biomed. Eng.
0090-6964,
30
(
7
), pp.
894
904
.
25.
Byun
,
H. S.
, and
Rhee
,
K.
, 2003, “
Intraaneurysmal Flow Changes Affected by Clip Location and Occlusion Magnitude in a Lateral Aneurysm Model
,”
Med. Eng. Phys.
1350-4533,
25
(
7
), pp.
581
589
.
26.
Lieber
,
B. B.
,
Livescu
,
V.
,
Hopkins
,
L. N.
, and
Wakhloo
,
A. K.
, 2002, “
Particle Image Velocimetry Assessment of Stent Design Influence on Intra-Aneurysmal Flow
,”
Ann. Biomed. Eng.
0090-6964,
30
(
6
), pp.
768
777
.
27.
Yu
,
S. C.
, and
Zhao
,
J. B.
, 1999, “
A Steady Flow Analysis on the Stented and Non-Stented Sidewall Aneurysm Models
,”
Med. Eng. Phys.
1350-4533,
21
(
3
), pp.
133
141
.
28.
Liou
,
T. M.
, and
Liou
,
S. N.
, 1999, “
A review on in vitro Studies of Hemodynamic Characteristics in Terminal and Lateral Aneurysm Models
,”
Proc. Natl. Sci. Counc Repub China B
0255-6596,
23
(
4
), pp.
133
148
.
29.
Liou
,
T. M.
,
Liou
,
S. N.
, and
Chu
,
K. L.
, 2004, “
Intra-Aneurysmal Flow With Helix and Mesh Stent Placement Across Side-Wall Aneurysm Pore of a Straight Parent Vessel
,”
ASME J. Biomech. Eng.
0148-0731,
126
(
1
), pp.
36
43
.
30.
Kohler
,
U.
,
Marshall
,
I.
,
Robertson
,
M. B.
,
Long
,
Q.
,
Xu
,
X. Y.
, and
Hoskins
,
P. R.
, 2001, “
MRI Measurement of Wall Shear Stress Vectors in Bifurcation Models and Comparison With CFD Predictions
,”
J. Magn. Reson Imaging
1053-1807,
14
(
5
), pp.
563
573
.
31.
Holdsworth
,
D. W.
,
Norley
,
C. J.
,
Frayne
,
R.
,
Steinman
,
D. A.
, and
Rutt
,
B. K.
, 1999, “
Characterization of Common Carotid Artery Blood-Flow Waveforms in Normal Human Subjects
,”
Physiol. Meas
0967-3334,
20
(
3
), pp.
219
240
.
32.
Ku
,
J. P.
,
Elkins
,
C. J.
, and
Taylor
,
C. A.
, 2005, “
Comparison of CFD and MRI Flow and Velocities in an in vitro Large Artery Bypass Graft Model
,”
Ann. Biomed. Eng.
0090-6964,
33
(
3
), pp.
257
269
.
33.
Glor
,
F. P.
,
Ariff
,
B.
,
Crowe
,
L. A.
,
Hughes
,
A. D.
,
Cheong
,
P. L.
,
Thom
,
S. A.
,
Verdonck
,
P. R.
,
Firmin
,
D. N.
,
Barratt
,
D. C.
, and
Xu
,
X. Y.
, 2003, “
Carotid Geometry Reconstruction: a Comparison Between MRI and Ultrasound
,”
Med. Phys.
0094-2405,
30
(
12
), pp.
3251
3261
.
34.
Masaryk
,
A. M.
,
Frayne
,
R.
,
Unal
,
O.
,
Krupinski
,
E.
, and
Strother
,
C. M.
, 1999, “
In vitro and in vivo Comparison of Three MR Measurement Methods for Calculating Vascular Shear Stress in the Internal Carotid Artery
,”
AJNR Am. J. Neuroradiol.
0195-6108,
20
(
2
), pp.
237
245
.
35.
Steinman
,
D. A.
, 2002, “
Image-Based Computational Fluid Dynamics Modeling in Realistic Arterial Geometries
,”
Ann. Biomed. Eng.
0090-6964,
30
(
4
), pp.
483
497
.
36.
Long
,
Q.
,
Xu
,
X. Y.
,
Ariff
,
B.
,
Thom
,
S. A.
,
Hughes
,
A. D.
, and
Stanton
,
A. V.
, 2000, “
Reconstruction of Blood Flow Patterns in a Human Carotid Bifurcation: A Combined CFD and MRI Study
,”
J. Magn. Reson Imaging
1053-1807,
11
(
3
), pp.
299
311
.
37.
Huang
,
J.
, and
van Gelder
,
J. M.
, 2002, “
The Probability of Sudden Death From Rupture of Intracranial Aneurysms: a Meta-Analysis
,”
Neurosurgery
0148-396X,
51
(
5
), pp.
1101
1107
.
38.
Millán
,
R. D.
,
Hernandez
,
M.
,
Gallardo
,
D.
,
Cebral
,
J. R.
,
Putman
,
C. M.
,
Dempere-Marco
,
L.
, and
Frangi
,
A. F.
, 2005, “
Charaterization of Cerebral Aneurysms Using 3D Moment Invariants
,”
Proc. SPIE
0277-786X,
5747
, pp.
743
754
.
39.
Jou
,
L. D.
,
Wong
,
G.
,
Dispensa
,
B.
,
Lawton
,
M. T.
,
Higashida
,
R. T.
,
Young
,
W. L.
, and
Saloner
,
D.
, 2005, “
Correlation Between Lumenal Geometry Changes and Hemodynamics in Fusiform Intracranial Aneurysms
,”
AJNR Am. J. Neuroradiol.
0195-6108,
26
(
9
), pp.
2357
2363
.
40.
Ma
,
B.
,
Harbaugh
,
R. E.
, and
Raghavan
,
M. L.
, 2004, “
Three-Dimensional Geometrical Characterization of Cerebral Aneurysms
,”
Ann. Biomed. Eng.
0090-6964,
32
(
2
), pp.
264
273
.
41.
Raghavan
,
M. L.
,
Ma
,
B.
, and
Harbaugh
,
R. E.
, 2005, “
Quantified Aneurysm Shape and Rupture Risk
,”
J. Neurosurg.
0022-3085,
102
(
2
), pp.
355
362
.
42.
Hoi
,
Y.
,
Meng
,
H.
,
Woodward
,
S. H.
,
Bendok
,
B. R.
,
Hanel
,
R. A.
,
Guterman
,
L. R.
, and
Hopkins
,
L. N.
, 2004, “
Effects of Arterial Geometry on Aneurysm Growth: Three-Dimensional Computational Fluid Dynamics Study
,”
J. Neurosurg.
0022-3085,
101
(
4
), pp.
676
681
.
43.
Rudin
,
S.
,
Bednarek
,
D.
,
Chityala
,
R.
,
Dinu
,
P.
,
Hoffmann
,
K.
,
Hussain
,
R.
,
Ionita
,
C.
,
Kyprianou
,
I.
,
Wang
,
Z.
, and
Wu
,
Y.
, 2004, “
High-Resolution Vascular Radiological Imaging
,”
Med. Phys.
0094-2405,
31
(
6
), pp.
1826
1827
.
44.
Chityala
,
R.
,
Hoffmann
,
K.
,
Ionita
,
C.
,
Bednarek
,
D.
, and
Rudin
,
S.
, 2004, “
Geometric Calibration of Micro-Cone-Beam CT System
,”
Med. Phys.
0094-2405,
31
(
6
), p.
1820
.
45.
Ionita
,
C.
,
Chityala
,
R.
,
Rudin
,
S.
,
Hoffmann
,
K.
,
Kyprianou
,
I.
, and
Bednarek
,
D.
, 2003, “
Cone-Beam CT of Vessel Phantoms: Comparison of Image Intensifier and High-Resolution Micro-Angiographic Systems
,”
Med. Phys.
0094-2405,
30
(
6
), p.
1423
.
46.
Ionita
,
C.
,
Chityala
,
R.
,
Kyprianou
,
I.
,
Dinu
,
P.
,
Rudin
,
S.
,
Hoffmann
,
K.
, and
Bednarek
,
D.
, 2004, “
LabView Algorithm for Control of Cone Beam Micro-CT Machine
,”
Med. Phys.
0094-2405,
31
(
6
), p.
1849
.
47.
Kyprianou
,
I.
,
Rudin
,
S.
,
Ionita
,
C.
,
Wu
,
Y.
,
Bednarek
,
D.
, and
Ganguly
,
A.
, 2002, “
A High-Resolution Rapid-Sequence Imaging System for Region of Interest Micro-Angiography
,”
Med. Phys.
0094-2405,
29
(
6
), p.
1355
.
48.
Chityala
,
R.
,
Hoffmann
,
K.
,
Ionita
,
C.
,
Rudin
,
S.
,
Bednarek
,
D.
,
Wu
,
Y.
, and
Kyprianou
,
I.
, 2003, “
Micro-Cone-Beam CT for Determination of Stent Coverage of Aneurysm Orifice
,”
Med. Phys.
0094-2405,
30
(
6
), p.
1423
.
49.
Katz
,
I. M.
,
Shaughnessy
,
E. J.
, and
Cress
,
B. B.
, 1995, “
A Technical Problem in the Calculation of Laminar Flow Near Irregular Surfaces Described by Sampled Geometric Data
,”
J. Biomech.
0021-9290,
28
(
4
), pp.
461
464
.
50.
Milner
,
J. S.
,
Moore
,
J. A.
,
Rutt
,
B. K.
, and
Steinman
,
D. A.
, 1998, “
Hemodynamics of Human Carotid Artery Bifurcations: Computational Studies With Models Reconstructed From Magnetic Resonance Imaging of Normal Subjects
,”
J. Vasc. Surg.
0741-5214,
28
(
1
), pp.
143
156
.
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