By Becca Bayham

Most people experience ultrasound technology either as a pregnant woman or a fetus. Ultrasound is also employed for cardiac imaging and for guiding semi-invasive surgeries, largely because of its ability to produce real-time images. And Kathy Nightingale, associate professor of biomedical engineering, is pushing the technology even further.

“We use high-frequency sound (higher than audible range) to send out echoes. Then we analyze the received echoes to create a picture,” Nightingale said at a Chautauqua Series lecture last Tuesday.

According to Nightingale, ultrasound maps differences in the acoustic properties of tissue. Muscles, blood vessels and fatty tissue have different densities and sound passes through them at different speeds. As a result, they show up as different colors on the ultrasound. Blood is more difficult to image, but researchers have found an interesting way around that problem.

“The signal from blood is really weak compared to the signal coming from tissue. But what you can do is inject microbubbles, and that makes the signal brighter,” Nightingale said.

Microbubbles are small enough to travel freely throughout the circulatory system — anywhere blood flows. Because fast-growing tumors require a large blood supply, microbubbles can be particularly helpful for disease detection.

Like most other electronics, ultrasound scanners have gotten smaller and smaller over the years. Hand-held ultrasounds “are not as fully capable as one of those larger scanners, just as with an iPad you don’t have as many options as your computer or laptop,” Nightingale said. However, the devices’ portability has earned them a place both on the battlefield and in the emergency room.

Nightingale’s research explores another aspect of ultrasonic sound — its ability to “push” on tissue at a microscopic scale. The amount of movement reveals how stiff a tissue is (which, in turn, can indicate whether tissue is healthy or not). It’s the same concept as breast, prostate and lymph node exams, but allows analysis of interior organs too.

“We can use an imaging system to identify regions in organs that are stiffer than surrounding tissue,” Nightingale said. “That would allow doctors to look at regions of pathology (cancer or scarring) rather than having to do a biopsy or cut someone open to look at something.”