Patient-specific computational fluid dynamics (CFD) is a powerful tool for researching the role of blood flow in disease processes. Modern clinical imaging technology such as MRI and CT can provide high resolution information about vessel geometry, but in many situations, patient-specific inlet velocity information is not available. In these situations, a simplified velocity profile must be selected. We studied how idealized inlet velocity profiles (blunt, parabolic, and Womersley flow) affect patient-specific CFD results when compared to simulations employing a “reference standard” of the patient’s own measured velocity profile in the carotid bifurcation. To place the magnitude of these effects in context, we also investigated the effect of geometry and the use of subject-specific flow waveform on the CFD results. We quantified these differences by examining the pointwise percent error of the mean wall shear stress (WSS) and the oscillatory shear index (OSI) and by computing the intra-class correlation coefficient (ICC) between axial profiles of the mean WSS and OSI in the internal carotid artery bulb. The parabolic inlet velocity profile produced the most similar mean WSS and OSI to simulations employing the real patient-specific inlet velocity profile. However, anatomic variation in vessel geometry and the use of a nonpatient-specific flow waveform both affected the WSS and OSI results more than did the choice of inlet velocity profile. Although careful selection of boundary conditions is essential for all CFD analysis, accurate patient-specific geometry reconstruction and measurement of vessel flow rate waveform are more important than the choice of velocity profile. A parabolic velocity profile provided results most similar to the patient-specific velocity profile.

References

References
1.
Ku
,
D. N.
, 1997, “
Blood Flow in Arteries
,”
Annu. Rev. Fluid Mech.
,
29
, pp.
399
434
.
2.
Ku
,
D. N.
,
Giddens
,
D. P.
,
Zarins
,
C. K.
, and
Glagov
,
S.
, 1985, “
Pulsatile Flow and Atherosclerosis in the Human Carotid Bifurcation. Positive Correlation Between Plaque Location and Low Oscillating Shear Stress
,”
Arteriosclerosis
,
5
(
3
), pp.
293
302
.
3.
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.
,
121
(
3
), pp.
265
272
.
4.
Steinman
,
D. A.
, 2004, “
Image-Based Computational Fluid Dynamics: A New Paradigm for Monitoring Hemodynamics and Atherosclerosis
,”
Curr. Drug Targets Cardiovasc. Haematol. Disord.
,
4
(
2
), pp.
183
197
.
5.
Wootton
,
D. M.
and
Ku
,
D. N.
, 1999, “
Fluid Mechanics of Vascular Systems, Diseases, and Thrombosis
,”
Annu. Rev. Biomed. Eng.
,
1
, pp.
299
329
.
6.
Lee
,
S. W.
and
Steinman
,
D. A.
, 2007, “
On the Relative Importance of Rheology for Image-Based CFD Models of the Carotid Bifurcation
,”
ASME J. Biomech. Eng.
,
129
(
2
), pp.
273
278
.
7.
Lee
,
K. W.
Wood
,
N. B.
and
Xu
,
X. Y.
, 2004, “
Ultrasound Image-Based Computer Model of a Common Carotid Artery With a Plaque
,”
Med. Eng. Phys.
,
26
(
10
), pp.
823
840
.
8.
Steinman
,
D. A.
, 2002, “
Image-Based Computational Fluid Dynamics Modeling in Realistic Arterial Geometries
,”
Ann. Biomed. Eng.
,
30
(
4
), pp.
483
497
.
9.
Augst
,
A. D.
,
Barratt
,
D. C.
,
Hughes
,
A. D.
,
Thom
,
S. A.
, and
Xu
,
X. Y.
, 2003, “
Various Issues Relating to Computational Fluid Dynamics Simulations of Carotid Bifurcation Flow Based on Models Reconstructed From Three-Dimensional Ultrasound Images
,”
Proc. Inst. Mech. Eng., Part H: J. Eng. Med.
,
217
(
5
), pp.
393
403
.
10.
Wake
,
A. K.
,
Oshinski
,
J. N.
,
Tannenbaum
,
A. R.
, and
Giddens
,
D. P.
, 2009, “
Choice of in vivo Versus Idealized Velocity Boundary Conditions Influences Physiologically Relevant Flow Patterns in a Subject-Specific Simulation of Flow in the Human Carotid Bifurcation
,”
ASME J. Biomech. Eng.
,
131
(
2
), p.
021013
.
11.
Moyle
,
K. R.
,
Antiga
,
L.
, and
Steinman
,
D. A.
, 2006, “
Inlet Conditions for Image-Based CFD Models of the Carotid Bifurcation: Is It Reasonable to Assume Fully Developed Flow?
,”
ASME J. Biomech. Eng.
,
128
(
3
), pp.
371
379
.
12.
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.
,
47
(
1
), pp.
149
159
.
13.
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.
,
28
(
1
), pp.
143
156
.
14.
Marzo
,
A.
Singh
,
P.
Reymond
,
P.
Stergiopulos
,
N.
Patel
,
U.
and
Hose
,
R.
, 2009, “
Influence of Inlet Boundary Conditions on the Local Haemodynamics of Intracranial Aneurysms
,”
Comput. Methods Biomech. Biomed. Eng.
,
12
(
4
), pp.
431
44
.
15.
Myers
,
J. G.
,
Moore
,
J. A.
,
Ojha
,
M.
,
Johnston
,
K. W.
, and
Ethier
,
C. R.
, 2001, “
Factors Influencing Blood Flow Patterns in the Human Right Coronary Artery
,”
Ann. Biomed. Eng.
,
29
(
2
), pp.
109
120
.
16.
Womersley
,
J. R.
, 1955, “
Method for the Calculation of Velocity, Rate of Flow and Viscous Drag in Arteries When the Pressure Gradient Is Known
,”
J. Physiol.
(London),
127
(
3
), pp.
553
563
.
17.
Heiberg
,
E.
,
Sjogren
,
J.
,
Ugander
,
M.
,
Carlsson
,
M.
,
Engblom
,
H.
, and
Arheden
,
H.
, 2010, “
Design and Validation of Segment–Freely Available Software for Cardiovascular Image Analysis
,”
BMC Med. Imaging
,
10
, p.
1
.
18.
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.
,
20
(
3
), pp.
219
240
.
20.
Marshall
,
I.
,
Papathanasopoulou
,
P.
, and
Wartolowska
,
K.
, 2004, “
Carotid Flow Rates and Flow Division at the Bifurcation in Healthy Volunteers
,”
Physiol. Meas
,
25
(
3
), pp.
691
697
.
21.
Wootton
,
D. M.
,
Markou
,
C. P.
,
Hanson
,
S. R.
, and
Ku
,
D. N.
, 2001, “
A Mechanistic Model of Acute Platelet Accumulation in Thrombogenic Stenoses
,”
Ann. Biomed. Eng.
,
29
(
4
), pp.
321
329
.
22.
www.vmtk.org.
23.
Antiga
,
L.
and
Steinman
,
D. A.
, 2004, “
Robust and Objective Decomposition and Mapping of Bifurcating Vessels
,”
IEEE Trans. Med. Imaging
,
23
(
6
), pp.
704
713
.
24.
Shrout
,
P. E.
and
Fleiss
,
J. L.
, 1979, “
Intraclass Correlations: Uses in Assessing Rater Reliability
,”
Psychol. Bull.
,
86
(
2
), pp.
420
428
.
25.
Suri
,
J. S.
,
Pattichis
,
C. S.
,
Li
,
C.
,
Macione
,
J.
,
Yang
,
Z.
,
Fox
,
M. D.
,
Wu
,
D.
, and
Laxminarayan
,
S.
, 2005, “
Plaque Imaging Using Ultrasound, Magnetic Resonance and Computer Tomography: A Review
,”
Stud. Health Technol. Inform.
,
113
, pp.
1
25
. Available at http://iospress.metapress.com/content/ptvwr6mn2he5lwha/
26.
Hoi
,
Y.
,
Wasserman
,
B. A.
,
Lakatta
,
E. G.
, and
Steinman
,
D. A.
, 2010, “
Effect of Common Carotid Artery Inlet Length on Normal Carotid Bifurcation Hemodynamics
,”
ASME J. Biomech. Eng.
,
132
(
12
), p.
121008
.
27.
He
,
X.
,
Ku
,
D. N.
, and
Moore
,
J. E.
, Jr.
, 1993, “
Simple Calculation of the Velocity Profiles for Pulsatile Flow in a Blood Vessel Using Mathematica
,”
Ann. Biomed. Eng.
,
21
(
1
), pp.
45
9
.
28.
Hoi
,
Y.
,
Wasserman
,
B. A.
,
Lakatta
,
E. G.
, and
Steinman
,
D. A.
, 2010, “
Carotid Bifurcation Hemodynamics in Older Adults: Effect of Measured Versus Assumed Flow Waveform
,”
ASME J. Biomech. Eng.
,
132
(
7
), p.
071006
.
29.
Hager
,
A.
,
Kaemmerer
,
H.
,
Rapp-Bernhardt
,
U.
,
Blücher
,
S.
,
Rapp
,
K.
,
Bernhardt
,
T. M.
,
Galanski
,
M.
, and
Hess
,
J.
, 2002, “
Diameters of the Thoracic Aorta Throughout Life as Measured With Helical Computed Tomography
,”
J. Thorac. Cardiovasc. Surg.
,
123
(
6
), pp.
1060
1066
.
30.
Ford
,
M. D.
,
Xie
,
Y. J.
,
Wasserman
,
B. A.
, and
Steinman
,
D. A.
, 2008, “
Is Flow in the Common Carotid Artery Fully Developed?
,”
Physiol. Meas.
,
29
(
11
), pp.
1335
1349
.
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