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Limited bifurcation asymmetry in coronary arterial tree models generated by constrained constructive optimization
W Schreiner1, F Neumann, M Neumann
1Department of Medical Computer Sciences, University of Vienna, Austria. wolfgang.schreiner@akh-wien.ac.at
The Journal of General Physiology
|February 1, 1997
Summary
Constrained constructive optimization (CCO) models of coronary arterial trees were improved by limiting bifurcation asymmetry. Tightening this constraint altered tree structure from direct to indirect blood delivery, increasing volume and surface area without affecting pressure profiles.
Area of Science:
- Biomedical Engineering
- Computational Biology
- Cardiovascular Physiology
Background:
- Coronary arterial tree models are crucial for understanding blood flow dynamics.
- Existing models using constrained constructive optimization (CCO) generate realistic structures but exhibit overly asymmetric bifurcations.
- The impact of bifurcation asymmetry on the global structure and function of these models requires further investigation.
Purpose of the Study:
- To investigate the effect of imposing a limit on bifurcation asymmetry within the CCO algorithm.
- To analyze how this new constraint influences the structural and functional characteristics of generated coronary arterial tree models.
- To understand the relationship between local bifurcation asymmetry and the overall optimized arterial tree structure.
Main Methods:
- Utilized the constrained constructive optimization (CCO) algorithm to generate binary branching networks representing coronary arterial trees.
- Introduced and varied an additional constraint limiting the asymmetry of bifurcations during the model construction process.
- Evaluated the structural and functional changes in the generated models using phenomenological observations and statistical descriptors, comparing them with physiological data.
Main Results:
- Imposing a limit on bifurcation asymmetry led to models where blood is conveyed via detours, shifting from a direct conveying to a delivering function.
- Total intravascular volume, surface area, and the sum of segment lengths increased as the asymmetry constraint was tightened.
- The pressure profile from the inlet to the terminals remained unaffected by the changes in bifurcation asymmetry and global structure.
Conclusions:
- Local bifurcation asymmetry is a key factor determining the global structure of optimized arterial tree models.
- The refined CCO algorithm with asymmetry constraints produces models that better reflect the functional specialization of coronary arteries.
- The study highlights the interplay between local geometric rules and global physiological function in vascular networks.