Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Aug;24(8):81901.
doi: 10.1063/1.4744984. Epub 2012 Aug 10.

Characterization of the transport topology in patient-specific abdominal aortic aneurysm models

Amirhossein Arzani  1 , Shawn C Shadden
Affiliations

Characterization of the transport topology in patient-specific abdominal aortic aneurysm models

Amirhossein Arzani et al. Phys Fluids (1994). 2012 Aug.

Abstract

Abdominal aortic aneurysm (AAA) is characterized by disturbed blood flow patterns that are hypothesized to contribute to disease progression. The transport topology in six patient-specific abdominal aortic aneurysms was studied. Velocity data were obtained by image-based computational fluid dynamics modeling, with magnetic resonance imaging providing the necessary simulation parameters. Finite-time Lyapunov exponent (FTLE) fields were computed from the velocity data, and used to identify Lagrangian coherent structures (LCS). The combination of FTLE fields and LCS was used to characterize topological flow features such as separation zones, vortex transport, mixing regions, and flow impingement. These measures offer a novel perspective into AAA flow. It was observed that all aneurysms exhibited coherent vortex formation at the proximal segment of the aneurysm. The evolution of the systolic vortex strongly influences the flow topology in the aneurysm. It was difficult to predict the vortex dynamics from the aneurysm morphology, motivating the application of image-based flow modeling.

PubMed Disclaimer

Figures

Figure 1
Figure 1
AAA computer models derived from MRI.
Figure 2
Figure 2
Volumetric flow rates prescribed at the inlet of the models.
Figure 3
Figure 3
Cross-sections used for displaying results.
Figure 4
Figure 4
Sagittal and transverse sections of the forward and backward FTLE fields, and sagittal section of velocity field for Patient 1 at different times of the cardiac cycle. The two points in the top transverse plane show where the sagittal plane intersects.
Figure 5
Figure 5
Sagittal and transverse sections of the forward and backward FTLE fields, and sagittal section of velocity field for Patient 2 at different times of the cardiac cycle. The two points in the top transverse plane show where the sagittal plane intersects.
Figure 6
Figure 6
Sagittal and transverse sections of the forward and backward FTLE fields, and sagittal section of velocity field for Patient 3 at different times of the cardiac cycle. The two points in the top transverse plane show where the sagittal plane intersects.
Figure 7
Figure 7
Sagittal and transverse sections of the forward and backward FTLE fields, and sagittal section of velocity field for Patient 4 at different times of the cardiac cycle. The two points in the top transverse plane show where the sagittal plane intersects.
Figure 8
Figure 8
Section of the forward and backward FTLE fields in Patient 4's iliac aneurysm at different times of the cardiac cycle.
Figure 9
Figure 9
Coronal (left) and sagittal (right) sections of the forward and backward FTLE fields, and velocity field for Patient 5 at different times of the cardiac cycle.
Figure 10
Figure 10
Transverse sections of FTLE in the proximal and distal lobes for Patient 5. The points show where the sagittal plane intersects.
Figure 11
Figure 11
Sagittal and transverse sections of the forward and backward FTLE fields, and sagittal section of velocity field for Patient 6 at different times of the cardiac cycle. The two points in the top transverse plane show where the sagittal plane intersects.
Figure 12
Figure 12
Comparison of different representations of FTLE for Patient 4. The figure is based on forward FTLE.
See this image and copyright information in PMC

References

    1. Salsac A. V., Sparks S. R., Chomaz J. M., and Lasheras J. C., “Evolution of the wall shear stresses during the progressive enlargement of symmetric abdominal aortic aneurysms,” J. Fluid Mech. 560, 19–52 (2006).10.1017/S002211200600036X - DOI
    1. Suh G. Y., Les A. S., Tenforde A. S., Shadden S. C., Spilker R. L., Yeung J. J., Cheng C. P., Herfkens R. J., Dalman R. L., and Taylor C. A., “Quantification of particle residence time in abdominal aortic aneurysms using magnetic resonance imaging and computational fluid dynamics,” Ann. Biomed. Eng. 39, 864–883 (2011).10.1007/s10439-010-0202-4 - DOI - PMC - PubMed
    1. Les A. S., Shadden S. C., Figueroa C. A., Park J. M., Tedesco M. M., Herfkens R. J., Dalman R. L., and Taylor C. A., “Quantification of hemodynamics in abdominal aortic aneurysms during rest and exercise using magnetic resonance imaging and computational fluid dynamics,” Ann. Biomed. Eng. 38, 1288–1313 (2010).10.1007/s10439-010-9949-x - DOI - PMC - PubMed
    1. Vorp D. A., “Biomechanics of abdominal aortic aneurysm,” J. Biomech. 40(9), 1887–1902 (2007).10.1016/j.jbiomech.2006.09.003 - DOI - PMC - PubMed
    1. Vorp D. A., Lee P. C., Wang D. H. J., Makaroun M. S., Nemoto E. M., Ogawa S., and Webster M. W., “Association of intraluminal thrombus in abdominal aortic aneurysm with local hypoxia and wall weakening,” J. Vasc. Surg. 34(2), 291–299 (2001).10.1067/mva.2001.114813 - DOI - PubMed

LinkOut - more resources