| Τύπος: |
Διάλεξη |
| Ημ/νία Έναρξης: |
5/12/2013 |
| Ημ/νία Λήξης: |
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| Ώρα Έναρξης: |
15:30 |
| Ώρα Λήξης: |
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| Ομιλητής: |
Καθηγητής Ανδρέας Αναγιωτός, Τμήμα Μηχανολόγων Μηχανικών και Επιστήμης και Μηχανικής Υλικών, Τεχνολογικό Πανεπιστήμιο Κύπρου (Αντιπρύτανης Οικονομικού Προγραμματισμού & Ανάπτυξης του ιδρύματος)
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| Τίτλος: |
Image-based geometric and hemodynamic modeling of arteries towards subject specific clinical treatment
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| Περιγραφή: |
Novel Clinical Imaging Techniques combined with Computational Fluid Dynamic techniques provide more detailed and accurate information not available with current clinical imaging techniques. This allows patient specific reconstruction of 3-D arterial geometries and hemodynamics for clinical analysis for better diagnostic and prognostic value. One application of this is the carotid bifurcation.
Head and neck rotation have been shown to cause changes in morphology and flow characteristics of the human carotid bifurcation (CB). This may influence parameters that have previously been cited as important in the development of atherosclerotic disease such as relative particle residence times (RRT), normalized oscillatory shear index (nOSI), wall shear stress temporal gradient (WSSTG) and helicity (HL).
To investigate the effect of head posture 10 healthy volunteers were imaged in two head postures: 1) the supine neutral and 2) the prone with rightward head rotation up to 80o. The blood flow velocity profile for each model was obtained using phase-contrast MRI (PC-MRI) at the common carotid artery (CCA) upstream of the CB. The results indicate that the blood flow waveform changes with posture change and blood flow shows reduction at peak systole, at the prone position in most cases for both the left and right carotid arteries in all volunteers. 3-D TOF MRI was used to segment the CB. 3-D image reconstruction techniques were used to construct computational models. Numerical simulations were performed and
the flow velocity, vorticity and wall shear stress fields were constructed for each model. The area exposure to unfavorable hemodynamics, based on thresholds set for nOSI, RRT was used to quantify the atherosclerotic burden of head posture on the wall. The distribution of WSSTG and HL in each model were also compared for the two postures. Differences in all parameters were observed for each posture in both the left and right CB models. Our results show that: Flow reduction and geometric changes in the CB due to head and neck rotation cause differences in the distribution of nOSI, RRT, WSSTG and HL indicating that head posture may be a factor to be considered in the genesis and development of atherosclerotic disease. Furthermore, it is a factor that should be considered with complications in stenotic and stented vessels.
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