While existing ultrasound technologies are able to identify plaque buildup on artery walls, determining when that plaque is at risk of breaking off, resulting in a heart attack or stroke, has proven a more complicated task. A team of researchers from North Carolina State University has now developed a dual-frequency ultrasound device that could help identify so-called vulnerable plaque and enable a more accurate diagnosis for at-risk patients.

Current approaches to detecting vulnerable plaque involve the use of a contrast agent called "micro-bubbles". Researchers have found that by injecting micro-bubbles into the bloodstream, they will be drawn to the molecules associated with vulnerable plaque, effectively highlighting these areas in ultrasound images.

According to the NC State researchers, the devices used in these approaches are not optimized for detecting contrast agents as they are designed for high-frequency mode imaging.

"So we’ve developed a dual-frequency intravascular ultrasound transducer which transmits and receives acoustic signals,” says Dr. Xiaoning Jiang, an NC State associate professor of mechanical and aerospace engineering and adjunct professor of biomedical engineering. "Operating on two frequencies allows us to do everything the existing intravascular ultrasound devices can do, but also makes it much easier for us to detect the contrast agents (microbubbles) used for molecular imaging."

The team has tested the prototype device in the laboratory and found it to perform well. It is now working to optimize the technology in hopes of launching pre-clinical studies in the near-future.

The team's research findings were published in the May issue of the journal IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control