题目：Biomechanical Analysis Based on Medical Imaging, Computational Fluid Dynamics, and Discrete Element Method

主讲人：Dr Kelvin Wong，Assistant Professor

Engineering Computational Biology, School of Computer Science and Software Engineering

The University of Western Australia

时间：2014年12月24号， 上午10:30-11:30

地点：307

报告摘要：Medical Imaging: Modelling of non-stationary cardiac structures is complicated by the complexity of their intrinsic and extrinsic motion. The first known study of haemodynamics due to the beating of heart was made by Leonardo Da Vinci, giving the idea of fluid-solid interaction by describing how vortices develop during cardiac structural interaction with the blood. Heart morphology affects in changes of cardio dynamics during the systolic and diastolic phrases. Using cardiac magnetic resonance imaging, we show that in a chamber of the heart, large-scale vortices are shown to exist as the result of the unique morphological changes of the cardiac chamber wall. As the characteristics of the flow vary over a cardiac cycle, there is a need for a robust quantification method to analyse vorticity and vortex circulation. Our success in the measurement of vortex characteristics opens up new ways of cardiac analysis that can potentially extend medical knowledge of hemodynamic behaviour in the heart. This enables the possibility of a visualisation system for analysing cardiac flow of blood. Such a tool can also be used to discover flow phenomena related to the heart. Many types of cardiac abnormality have an implication on blood flow. However, most present-day diagnostic modalities analyse myocardial structures and not the cardiac flow within to detect heart defects in vivo. In this presentation, it can be demonstrated how such a proposed computerised system can provide a non-invasive approach for scanning humans with heart abnormalities, and be utilised in the management of cardiac patients.

Computational Hemodynamics: We also present the use of Computational fluid dynanmics in cardiovascular analysis. Hemodynamics plays an important role in the development and progression of plaque that prone on cites of curvatures and bifurcations. CFD techniques were used to determine the hemodynamics parameters in transient simulated cardiovascular models to explore the effects of blood flow in these structures.

Discrete Element Cell Modelling: We present a new framework for modelling biological systems based on discrete particles. Collections of discrete particles are employed to represent cell components (e.g. cell membranes, cell cytoskeleton, cell nucleus) and extracellular matrix (e.g. collagen). Virtual interactions between particles can be used to represent many physical interaction types (e.g. cell-cell adhesion via cadherins, integrin basement membrane attachment, cytoskeletal mechanical properties).

报告人简介： Dr. Kelvin KL Wong has experience in the field of medical imaging, flow visualization and biofluid mechanics. He is currently Assistant Professor (Biomedical Engineering) at University of Western Australia. In his research career, he was a research fellow at RMIT University for two years and was visiting research scientist at Tsinghua University for a year, working on the hemodynamics and the CFD study of blood flow through arteries. Whilst undertaking his Ph.D. at the University of Adelaide, he pioneered medical imaging processing software named Medflovan that is able to decipher, visualize and analyse cardiac flow activities. The software also comes with the capability to reconstruct 3D velocity-encoded phase contrast magnetic resonance images, and his prototype resulted in a provisional patent, as well as three international conference awards. Application of Dr. Wong’s Medflovan has resulted in numerous peer-reviewed journal publications related to cardiovascular engineering and biomechanics, and the software has been licensed as freeware to the relevant research teams that he has collaborated with. Dr Wong has served as a visiting research scientist in Tsinghua University studying pebble flow mechanics in nuclear reactors. He is actively researching in discrete element methods and its application in cell modelling.