Tiny ultrasound stickers a breakthrough in continuous real-time imaging
Engineers at MIT have designed a tiny sticker that can deliver continuous ultrasound images of internal organs for up to 48 hours. The innovation is a step towards a future where stickers could wirelessly track muscle health during workouts or fetal development during pregnancy.
Ultrasound imaging is perhaps the safest and most used form of medical imaging. Yet it still requires a trip to the doctor’s office and bulky equipment.
Everyone who has had an ultrasound will be familiar with the squirt of thick, cold gel on their skin before the probe is applied. This gel is necessary for the ultrasound waves to be clearly transmitted from the probe to one’s internal organs and back again. Over time, this gel can dry or run off the skin, therefore needing constant reapplication for longer ultrasound procedures.
One of the biggest new innovations in this MIT development is the creation of a hydrogel that is encapsulated within a thin elastomer membrane. This creates a perfect stretchy, elastic material that can sit on skin while effectively transmitting ultrasound waves.
“The elastomer prevents dehydration of hydrogel,” explained co-lead author Xiaoyu Chen. “Only when hydrogel is highly hydrated can acoustic waves penetrate effectively and give high-resolution imaging of internal organs.”
The other part of the device contains a rigid array of hundreds of tiny ultrasound transducers. Co-lead-author Chonghe Wang said this pairing of a dense array of transducers with the stretchy hybrid of elastomer and hydrogel allows the sticker to consistently image internal organs over long periods of time.
“This combination enables the device to conform to the skin while maintaining the relative location of transducers to generate clearer and more precise images,” said Wang.
A new study published in the journal Science describes the device being tested across an assortment of applications, from jogging to lifting weights. This demonstrated the extraordinary potential of the new device to deliver ultrasound imaging of human activities in ways never before seen.
Using the device the researchers were able to watch a stomach expand and then shrink as a volunteer drank a glass of juice. Other tests demonstrated how the device can monitor muscles as a person lifts weights, potentially informing a wearer when they should stop exercising before damage is done.
“With imaging, we might be able to capture the moment in a workout before overuse, and stop before muscles become sore,” speculated Chen. “We do not know when that moment might be yet, but now we can provide imaging data that experts can interpret.”
At the moment the device is not wireless but even in its current form the researchers suggest there are immediate real-world applications. Hospitals could currently use it for real-time monitoring of heart patients, for example.
But the future potential for this kind of device is more exciting. The team is currently working on making the device operate wirelessly, so it could then hypothetically communicate with a smartphone app. Ultrasound stickers could be produced for any number of uses, from exercise tracking, to long-term monitoring of suspect tumors. Pregnancies could even be tracked in real-time from home.
“We envision a few patches adhered to different locations on the body, and the patches would communicate with your cellphone, where AI algorithms would analyze the images on demand,” said 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.”
The new study was published in the journal Science.