Ultrasound as an imaging technique has several things going for it. For one, it's more affordable than CT and MRI scans, and it's portable, so it can easily travel to rural and low-infrastructure areas or patients who are house-bound. And unlike with CT scans and X-rays, there is no ionizing radiation exposure, hence its widespread use imaging fetuses in pregnant women.
Unfortunately, the high-frequency soundwave approach to viewing soft tissue doesn't provide great resolution, so despite all its perks, it's not the go-to imaging tech for cancer detection. Now, thanks to a new discovery out of the University of North Carolina School of Medicine, that may soon change.
By combining ultrasound imaging with a special contrast agent, researchers say they've been able to greatly improve the resolution -- and consequently tumor-detecting ability -- of sonograms. Reporting this week in PLOS ONE, the biomedical engineers say they were able to visualize lesions created by a malignant cancer that forms on blood vessel walls called angiosarcoma.
The secret, it turns out, is in the contrast agent, which is made up of microbubbles that bind to the protein SFRP2. One of the researcher's labs was the first to discover that this type of cancer produces an excess amount of SFRP2, so by using a contrast agent that targets the culprit protein, they were able to visualize the malignant tumors in detail.
"In contrast, there was no visualization of normal blood vessels," said professor of surgery Nancy Klauber-DeMore in a school news release. "This suggests that the contrast agent may help distinguish malignant from benign masses found on imaging."
For this work, the researchers injected the microbubble contrast agent into mice and tracked it using ultrasound. And because SFRP2 is expressed in many cancer types, from kidney and pancreas to breast and colon, and increases as tumors develop, Klauber-DeMore said the next step is to see whether they can use this imaging tech to detect very small tumors as well as track tumor growth.
Ultrasound may never overtake extremely powerful imaging techniques like CT and MRI, but if it is in fact able to visualize tiny tumors and discern malignant from benign ones, it could very well become an affordable alternative in many parts of the world.