Image guided therapies, such as new endovascular procedures for treating brain aneurysms are now in clinical use. To plan these procedures, physicians currently use angiography to view projectional images of anatomy and blood flow. There are currently no available tools for visualizing the details of complex blood flow or predicting the effects of specific treatments. To address this problem, we have created a virtual environment for the visualization of blood flow and the simulated effects of therapy in brain aneurysms. The “Virtual Aneurysm” is composed using a combination of image processing, flow simulation, scientific visualization, and virtual reality techniques.

Our approach is to begin with angiographic sequences of clinical aneurysms. Image processing, reconstruction, and flow quantitation techniques are to used extract three dimensional geometry and bulk blood flow data. After building the geometric model (including any proposed embolic material insertions), this data is used as input to a computational fluid dynamics program. Using the geometry, arterial inflow, blood properties, and a physical flow model (Navier-Stokes), transient velocity and pressure fields can be computed throughout the aneurysm over one heart beat. Dynamic flow results are then organized in an object-oriented database for use in the interactive visualization system. A virtual environment is used to allow a physician to move around and into the aneurysm. Virtual tools are directly manipulated to explore the flow and gain insight into the transient pressure, velocity, and stress fields. The effects of a proposed interventional procedure on aneurysm wall stress can be viewed. The end result should be better understanding of aneurysm anatomy, hemodynamics, and response to proposed treatment. Furthermore, we hope that greater knowledge of aneurysm hemodynamics will lead to better understanding of aneurysm etiology and pathology.