Annals of Biomedical Engineering

, Volume 42, Issue 4, pp 787–796

Contrast Agent Bolus Dispersion in a Realistic Coronary Artery Geometry: Influence of Outlet Boundary Conditions

Authors

    • Section of Medical Physics, Department of RadiologyJohannes Gutenberg University Medical Center
  • Regine Schmidt
    • Section of Medical Physics, Department of RadiologyJohannes Gutenberg University Medical Center
  • Dirk Graafen
    • Section of Medical Physics, Department of RadiologyJohannes Gutenberg University Medical Center
  • Hanns-Christian Breit
    • Section of Medical Physics, Department of RadiologyJohannes Gutenberg University Medical Center
  • Laura M. Schreiber
    • Section of Medical Physics, Department of RadiologyJohannes Gutenberg University Medical Center
Article

DOI: 10.1007/s10439-013-0950-z

Cite this article as:
Sommer, K., Schmidt, R., Graafen, D. et al. Ann Biomed Eng (2014) 42: 787. doi:10.1007/s10439-013-0950-z

Abstract

Myocardial blood flow (MBF) quantification using contrast-enhanced first-pass magnetic resonance imaging relies on the precise knowledge of the arterial input function (AIF). Due to vascular transport processes, however, the shape of the AIF may change from the left ventricle where the AIF is measured to the myocardium. We employed computational fluid dynamics simulations in a realistic model of the left circumflex artery to investigate the degree to which this effect corrupts MBF quantification. Different outlet boundary conditions were applied to examine their influence on the solution. Our results indicate that vascular transport processes in realistic coronary artery geometries give rise to non-negligible systematic errors in the MBF values. The magnitude of these errors differs considerably between the outlets of the 3D model. Moreover, outlet boundary conditions are shown to have a significant influence on the outflows at the outlets of the 3D model. In particular, the employed boundary conditions respond differently to an artificially inserted stenosis and to hyperemia condition. Finally, outlet boundary conditions are shown to have an influence on the resulting MBF value. Since MBF errors are different under rest and under hyperemia conditions, overestimation of myocardial perfusion reserve values may occur as well.

Keywords

PerfusionMRIMBFVascular transportComputational fluid dynamicsStenosisArterial input function

Supplementary material

View video

The supplemental video shows the transport of an injected contrast agent bolus for the resistance boundary condition without vasodilation at physical rest condition and without stenosis. For better visualization of contrast agent dispersion, a “delta bolus”, i.e., a very short version (approximately 0.5 s) of the original bolus is used as inlet boundary condition. (AVI 49033 kb)

Copyright information

© Biomedical Engineering Society 2013