Dual Frequency Ultrasound Transducer prototype: Photo: Xiaoning JiangPlaque
is not a good thing, especially when it develops in our arteries. When
ultrasound procedures reveal that we have atherosclerosis, coronary
artery disease, or peripheral artery disease, what our doctors don’t
know is how likely we are to suffer a stroke or heart attack from that
condition, because current ultrasound technology cannot make that
assessment.
Researchers at the University of North Carolina,
Chapel Hill, and North Caroline State University are working on new intravascular ultrasound
technologies that will be able to determine whether arterial plaque is
‘vulnerable’ enough to detach from artery walls and cause a heart attack or
stroke. What makes the plaque vulnerable to breaking off is the invasion
of small blood vessels, vasa vasorum, that normally feed arteries and veins, but can wind up entering the plaque.
The
research team is working on two techniques that will be able to
identify vasa vasorum in plaque. Both procedures use contrast microbubbles – microbubbles that are colored with dye so that they will show up in imaging. In one
technique, microbubbles are injected into the artery, where they
highlight where the blood is flowing. The second technique involves other microobubbles that tartget molecules that are likely to be found in vulnerable plaques.
But
contrast dyes are not something current intravascular ultrasound
devices are well-suited to pick up. So the team developed a
dual-frequency intravascular ultrasound transducer which transmits and
receives acoustic signals. Operating on two frequencies allows the researchers to obtain all the information provided by current ultrasound devices, as well as allows them to identify the vaso vasorum and the molecular material in the plaque.
The new device is working in the lab, and refinements are continually being made, but the team expects to begin pre-clinical testing of their methods soon.
