Mason Researchers Unveil New Blood Flow Simulation System for Diagnosing Brain Aneurysms

Posted: June 9, 2008 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am

Mason researchers at Inova Fairfax Hospital
Mason researchers Rainald Löhner and Juan Cebral, standing, with Christopher Putman, director of the Interventional Neuroradiology Unit at Inova Fairfax Hospital, view images produced by the researchers’ newly unveiled bloodflow simulation system.

By Marjorie Musick

Researchers at Mason’s Center for Computational Fluid Dynamics recently unveiled a first-of-its-kind patient-specific blood flow simulation system that was assembled by Philips Medical Systems using software components developed at Mason. The cutting-edge technology has the potential to improve diagnostics and treatments for millions of Americans affected by brain aneurysms — saclike bulges in the blood vessels — each year.

Video: Center for Computational Fluid Dynamics Research.

“The problem with aneurysms is that when they rupture, they can cause hemorrhagic strokes (bleeding into the brain) leading to permanent cerebral damage,” says Rainald Löhner, director of the research center.

“This tool gives physicians a piece of information that is thought to be crucial for determining which aneurysms are likely to rupture and therefore require immediate and aggressive intervention.”

researchers studying images
Löhner discusses the interpretation of bloodflow simulation images with Putman, while Cebral examines images.

A multidisciplinary team comprised of Mason’s computational scientists, Inova Fairfax Hospital’s neuroradiologists and Philips Medical System’s engineers worked on the system. They produced the application to provide neurologists with hemodynamic (blood flow) information that is believed to be of fundamental importance for understanding the evolution and rupture process of brain aneurysms.

“Aneurysms are known to be a high-prevalence disease — an estimated 5 percent of the population has undetected aneurysms — so a lot of us have them without knowing it,” says Löhner. “How do doctors determine which ones to treat? This is a key question that this tool may help to answer.”

Information collected from the device will also aid clinicians in predicting the blood flow alterations produced by various interventions, including bypass surgery and the deployment of stents or coils in the blood vessels.

“With this tool, what was once observational now becomes predictable because it allows us to hypothesize and test theories about aneurysm treatment,” says Juan R. Cebral, associate professor in Mason’s Department of Computational and Data Sciences and principal investigator of the blood flow simulation system project.

Lohner, Cebral and Putnam at Inova Fairfax Hospital
Löhner, Cebral and Putman study the Phillips scanning unit that comprises part of the team’s bloodflow simulation system.
Photos by Nicolas Tan

“Image-based patient-specific computational modeling is useful because it can transform medicine from an observational science to a predictive science in which you can forecast the outcome of interventions based on mathematical calculations.”

How does it work?

Cebral explains the system this way: “An X-ray scanner takes pictures of the patient’s brain arteries during an intra-arterial injection of a dye that is opaque to the X-rays. These pictures are transferred to a workstation that creates a three-dimensional image of the blood vessels.

“Using these images, the new system allows the physicians to construct patient-specific computational models of the blood flow in the aneurysms, and to visualize the pressure differences, blood speed and wall shear stress (frictional forces on the aneurysm wall that are believed to influence the biology and structure of the arterial wall).”

“This technology represents a milestone in simulation-based medical imaging,” says Löhner. “It’s just the tip of the iceberg in what’s ahead for computer-aided medicine.”

Löhner notes that the project was made possible thanks to the close collaboration with Christopher Putman, M.D., director of the Interventional Neuroradiology Unit at Inova Fairfax Hospital, as well as the involvement and support of Roel Hermans, 3D imaging scientist, X-ray predevelopment, for Philips Medical Systems.

“Most advances in science are done on the fringes, and this system is a good example of this,” says Löhner.

“We are very excited about the benefits that this technology will bring to the medical community and its patients, but before that happens, we need to identify the specific hemodynamic variables and mechanisms that are associated with aneurysm rupture. This is the focus of our current research.”

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