Little patch that can see inside the body
When doctors want live images of a patient’s internal organs, they often turn to ultrasound imaging for a safe and non-invasive window into the body’s workings. To capture an image, technicians manipulate ultrasound wands and probes to direct sound waves into the body. These waves reflect back out and are used to produce high-resolution images of a patient’s heart, lungs, and other deep organs. Ultrasound imaging currently requires bulky and specialised equipment available only in hospitals and doctor’s offices. However, a new design developed by engineers at the Massachusetts Institute of Technology (MIT) and published in Science in late July might make the technology as wearable and accessible as buying Band-Aids at the chemist.
The postage-stamp-sized patch sticks to the skin and can provide continuous high-resolution ultrasound imaging of major blood vessels and organs such as the heart, lungs, and stomach for 48 hours. In the current design, the stickers — which have a strong adhesion — must be connected to instruments that translate the reflected sound waves into images. So they would be ideal for hospital patients — much like 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 research team ultimately wants to make the patches work wirelessly. If successful, they could be made into wearables that patients could take home from the doctor’s surgery or even buy at a pharmacy.
“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, professor of mechanical engineering and civil and environmental engineering at MIT. “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 team have already run the patch through a battery of lab tests with healthy volunteers, who wore the patches on various parts of their bodies, including the neck, chest, abdomen and arms. The patches stayed attached and produced clear images for up to 48 hours. During this time, the volunteers performed a variety of functions, from sitting and standing, to jogging, biking and lifting weights.
From the patches’ images, the team was able to observe the changing diameter of major blood vessels when seated versus standing. The patches also captured details of deeper organs, such as how the heart changes shape as it exerts during exercise; how the stomach distends, then shrinks back as volunteers drank then later passed juice out of their system. When volunteers lifted weights, the team could detect bright patterns in underlying muscles, signalling temporary microdamage.
“With imaging, we might be able to capture the moment in a workout before overuse, and stop before muscles become sore,” says co-lead author Xiaoyu Chen. “We do not know when that moment might be yet, but now we can provide imaging data that experts can interpret.”
The engineering team is also developing software algorithms based on AI that can better interpret and diagnose the patches’ images. Zhao envisions ultrasound patches could be packaged and purchased by patients and consumers, and used not only to monitor various internal organs, but also the progression of tumours, as well as the development of a fetus in the womb.
“We imagine we could have a box of [patches], each designed to image a different location of the body,” Zhao says. “We believe this represents a breakthrough in wearable devices and medical imaging.”
TOP The adhesive patch that produces ultrasound images of the body
PHOTO Felice Frankel