•The team hopes that they can soon develop a wireless variant.
•Currently, ultrasound imaging requires bulky and specialised equipment available only in hospitals.
Researchers from the Massachusetts Institute of Technology (MIT) have created a stamp-sized sticker that can provide images of internal organs continuously for 48 hours.
The design requires connecting the stickers to instruments that translate the reflected sound waves into images.
The researchers applied the stickers to volunteers and showed the devices produced live, high-resolution images of major blood vessels and deeper organs such as the heart, lungs, and stomach.
"We envision a few patches adhered to different locations on the body, and the patches would communicate with your cellphone, where AI algorithms would analyse the images on demand," says the study's senior author, Xuanhe Zhao.
"We believe we've opened a new era of wearable imaging: With a few patches on your body, you could see your internal organs."
Currently, ultrasound imaging requires bulky and specialised equipment available only in hospitals and special places. But the new design might make the technology as wearable and accessible as buying Band-Aids at the pharmacy.
The researchers tested the stickers on volunteers who performed various activities like sitting, standing, jogging and biking, observing that it was still adhesive and captured all the changes in the underlying organs.
They point out even in their current form, the stickers are ready for use and could be rolled out to patients in hospital, similar to heart-monitoring EKG stickers, and could continuously image internal organs without requiring a technician to hold a probe in place for long periods of time.
The team hopes that they could soon come up with stickers that are wireless so that they could be made into wearable imaging products that patients could take home from a doctor's office or even buy at a pharmacy.
What makes it special
At the moment, to image with ultrasound, a technician first applies a liquid gel to a patient's skin, which is necessary to transmit ultrasound waves.
A probe, or transducer, is then pressed against the gel, sending sound waves into the body that echo off internal structures and back to the probe, where the echoed signals are translated into visual images.
With the MIT team's new ultrasound sticker, they saw that despite the size, it produced higher resolution images over a longer duration by pairing a stretchy adhesive layer with a rigid array of transducers.
"This combination enables the device to conform to the skin while maintaining the relative location of transducers to generate clearer and more precise images." Wang said.
Unlike traditional ultrasound gels, the MIT team's hydrogel is elastic and stretchy.
"The elastomer prevents dehydration of hydrogel," says Chen, an MIT postdoc.
"Only when the hydrogel is highly hydrated can acoustic waves penetrate effectively and give high-resolution imaging of internal organs."
They are also developing software algorithms based on artificial intelligence that can better interpret the stickers' images.
They hope they can not only be used to monitor various internal organs, but also the progression of tumours, as well as the development of foetuses in the womb.
"We imagine we could have a box of stickers, each designed to image a different location of the body," Zhao says.
"We believe this represents a breakthrough in wearable devices and medical imaging."
Their study was published in the Journal Science.