Researchers from North Carolina State University, Raleigh, and the University of North Carolina at Chapel Hill have developed an ultrasound device that, they say, could help identify “vulnerable” arterial plaque, which is at high risk of breaking loose and causing heart attack or stroke. Existing state-of-the-art technologies can determine if arterial plaque is present, but cannot determine if it is vulnerable.

Two ultrasound techniques can help identify vulnerable plaques, but both require contrast agents called “microbubbles.” The first technique is to identify “vasa vasorum” in arteries. These are clusters of small blood vessels that infiltrate arterial plaque and through which microbubbles will flow highlighting them on ultrasound images.

The second technique is called molecular imaging, and relies on the use of “targeted” microbubbles. These microbubbles attach themselves to specific molecules that are more likely to be found in vulnerable plaques, making the plaques stand out on ultrasound images.

But existing intravascular ultrasound technology is not very good at detecting contrast agents, says Dr. Xiaoning Jiang, an NC State associate professor of mechanical and aerospace engineering, an adjunct professor of biomedical engineering.

The researchers developed a dual-frequency intravascular ultrasound transducer that transmits and receives acoustic signals. By operating on two frequencies, the device does everything existing intravascular ultrasound devices can, but also allows the easier detection of contrast agents or microbubbles.

The prototype device has performed well in laboratory testing, but the researchers say they are continuing to optimize the technology. They hope to launch pre-clinical studies in the near future.