University of Houston professor Ioannis Kakadiaris (right) and PhD student Sean O'Malley examine intravascular ultrasound data recorded in a coronary artery of a patient suffering from atherosclerosis. The original recording is analyzed in multiple ways to highlight the possible presence of vasa vasorum microcapillaries.
A software tool can measure the activity of plaque in blood vessels to identify patients at high risk of suffering a heart attack. “For the first time, this new imaging technology will provide doctors with the ability to detect inflamed plaque that represents regions of blood vessels [known as vulnerable plaque] prone to future rupture and sudden blockage,” says Ioannis Kakadiaris, professor of computer science at the University of Houston.
Detecting vulnerable plaque early is a major hurdle in the field of cardiology, says Kakadiaris, who is director of the university's Computational Biomedicine Lab. When plaque ruptures and blocks blood flow, it can cause a heart attack. The new computer technology should help physicians find this potentially fatal risk before it's too late. It differs from other technologies, such as traditional intravascular ultrasound and optical coherence tomography, which produce images of the structure of atherosclerotic plaque. The new tool takes images of vasa vasorum, the blood vessels on the outside of an artery, to measure the activity of plaque.
The researchers combined intravascular ultrasound with microbubble contrast agents to create a software tool that produces real-time cross-sectional views of an artery. It draws attention to the areas with dense vasa vasorum and possible inflammation. “Both metabolic activity and inflammation of plaque can be assessed by imaging the density and perfusion of vasa vasorum,” says Kakadiaris. “The more density or perfusion, the more vulnerable the plaque is.”
The vasa vasorum imaging technology can be used on any catheter-based plaque-imaging platform. Although it also works with existing intravascular ultrasound catheters, it functions best when used with a customized catheter for controlled delivery of a contrast-enhanced agent, says Kakadiaris. The software platform has been created, and the team is now working to design the first contrast-enhanced intravascular ultrasound catheter and plaque-specific microbubbles.
Kakadiaris invented the technology with Morteza Naghavi, MD, founder of the Association for Eradication of Heart Attack. They're collaborating with a number of researchers on studies from various universities and foundations worldwide. The Division of Information and Intelligent Systems of the National Science Foundation has supported Kakadiaris's work through a grant of more than $500,000.