Research

Systemic Physiology Modeling

The incredible complexities of the cardiovascular system can be approximated via simplified circuit representations. Using this approach, we describe the behaviours of different cardiovascular system components such as contractility, vascular impedance, atrio-ventricular synchronization, auto-regulation, etc, and perform 0D simulations of pressure and flow for different disease conditions and physiologic states. In one example project, we introduce various dysfunctions, such as limited heart rate and impaired respiration, into a virtual patient with single-ventricle circulation, and studied the resulting exercise performance.

The CMERL continues to use clinical and literature data to construct, improve, and validate these physiology models. This research area provides a mean to predict global physiologic responses and investigate systemic mechanisms affecting cardiovascular performance.

Lumped-parameter circuit physiology model describing the single-ventricle circulation Lumped-parameter physiology model describing the single-ventricle circulation
Image-based Computational Fluid Dynamics

Each patient has unique blood flow characteristics based on their specific anatomy and physiology. The CMERL uses clinical imaging data to construct 3D models of patient-specific anatomy, as well as to determine flow conditions affecting the relevant anatomical regions. Coupling 3D models to systemic physiology, we perform multi-scale simulations to investigate the interactions between local and global hemodynamics. "Virtual surgeries" can also be performed computationally to predict the effects of different surgical scenarios and disease conditions. The applications of this research area include surgical design/prediction, risk stratification for adverse hemodynamic events, and biomechanics investigations.

Patient-specific virtual surgery prediction of pressure distribution in stage 2 Fontan procedure Patient-specific virtual surgery prediction of pressure distribution in stage 2 Fontan procedure
In-vitro Experimental Validation

Materializing virtual simulations into the real physical world is when rubber meets the road. The CMERL constructs in-vitro flow systems which are direct parallels of multi-scale computational simulations, and performs direct measurements in the flow system using sensors and medical imaging. This provides points of comparison and validations for computational simulations. The techniques developed in the process also become useful in creating a real-world physical "mimic" of the human cardiovascular system.

Flow system and sensors setup with a patient-specific abdominal aortic aneurysm phantom Flow system and sensors setup with a patient-specific abdominal aortic aneurysm flow phantom
Medical Device & Treatment Testing

Uitilizing combinations of experimental techniques and computational models, the CMERL creates physiologically-realistic benchtop experimental environments to test the performance of medical devices and to predict the results of cardiovascular procedures and treatments. We design the test setups to mimic human body in various aspects depending on the relevant targets to be tested. These studies provide important information towards the the design of devices, and translation of novel treatment ideas, before placing real patients at risk during clinical trials.

This research also pioneers new possibilities for personalized medicine, where in-vitro patient-specific testing can be done prior to medical decision, treatment, or device installation. Such a step forward could transform the current paradigms of clinical procedures.

Testing setup to evaluate therapeutic thermal dose delivered by high-intensity focused ultrasound Testing setup to evaluate therapeutic thermal dose delivered by high-intensity focused ultrasound