There are two kinds of coronary plaque: hard (calcified or “stable”) and soft (“unstable”).
The calcium score test measures the degree of calcified deposits inside the coronary arteries, but not the degree or extend of soft plaque.
The soft plaque in coronary arteries can rupture and cause a blockage, leading to a heart attack or stroke. That’s why it’s also commonly referred to as “unstable.”
Researchers from the University of North Carolina at Chapel Hill and North Carolina State University have developed a method to identify this plaque—without the radiation exposure of a CT angiogram. Their ultrasound techniques use “microbubbles.”
The first technique identifies the vasa vasorum in arteries, clusters of small blood vessels that often invade plaque; they indicate the presence of soft plaque.
Microbubbles are injected into the artery and follow the blood flow.
When vasa vasorum is present, the microbubbles will flow through it, lighting up the image.
The second technique uses targeted microbubbles. Soft plaque is more likely to have certain molecules.
The microbubbles attach themselves to these, highlighting the image. “…we’ve developed a dual-frequency intravascular ultrasound transducer which transmits and receives acoustic signals,” says Dr. Xiaoning Jiang.
The new technology continues to be developed and currently has been limited to the laboratory setting.
Many people are walking around with severe coronary artery disease and don’t even know it.
