Simulation of Blood Flow and Contrast Medium Propagation for a Vascular Interventional Radiology Simulator

Minimally invasive technique provides a revolutionized clinical therapy, which significantly reduces operation trauma, recovery time, and overall clinical costs. Interventional radiologists use this technique to access vascular systems, and use catheterization to navigate to the region of interest with the help of the medical imaging technique. Medical education and training offer a virtual clinical environment for doctors to have highly qualified professional skills, and to provide high-quality care to patients. This project is mainly based on a framework of virtual catheterisation simulator (VCSim) developed in St Mary’s hospital, Imperial College London. This simulator models instruments using a mass-spring model, and provides interfaces with interventional radiology specific haptic devices. Clinicians are able to use this simulator to practice catheterization through different realistic vascular models. However, during virtual fluoroscopy, the vascular surfaces cannot be seen clearly without medical contrast medium which highlights the vessels. With the effect of beating blood flow produced by heart rate, contrast medium mixes and propagates through vasculature and allows visualisation of the blood vessels. This is called an angiography. This project aims to simulate blood flow and contrast medium propagation in three dimensional virtual vasculatures reconstructed from real patient CT scans. The useful information such as bifurcation and cross-section of vasculature are obtained from the corresponding centreline generated from patient datasets and processed through a centreline reconstruction tool. The blood flow is controlled by a beating heart model, interacting with the contrast medium propagation. The contrast medium is modelled using smoothed-particle hydrodynamics, and is constrained by three forces produced by initial injection, collision with vessel walls and beating blood flow. Moreover, an infinite number of injections are possible, and an initial review system, based on snap shot of the injection, is proposed. Furthermore, this project uses a haptic device to track a real catheter and control its virtual counterpart. On the same model, a real syringe is used to inject virtual contrast medium through the catheter as a clinician would do in real life. The simulation is tested in three different vasculatures, and theoretically supports complex vasculatures with a large number of branches and sub-branches. Further, the simulation is evaluated both by clinicians and through comparison with real injection videos. The result is convincing and can be used as the foundation of a more realistic contrast medium under specific and complex blood flow cases. This MSc individual project is developed under the supervision of Dr. Fernando Bello and Dr. Vincent Luboz at St Mary’s hospital, Imperial College London.