Wearable Ultrasound Measures Tissue Stiffness Under Skin

Researchers at the University of California San Diego have developed a wearable ultrasound patch that is intended to provide information on the stiffness of underlying tissues as deep as 4 cm below the surface of the skin. The patch consists of a flexible 16 x 16 ultrasonic array with a silver-epoxy composite backing layer that is designed to absorb excessive vibrations. It can provide tissue stiffness data, which could be useful in a wide array of medical scenarios, including monitoring liver cirrhosis, cancer progression, sports injuries, and myocardial ischemia. The technology is part of a new wave of wearable ultrasound devices that are set to allow continuous ultrasound monitoring on the move.

Traditional ultrasound technology has a long history of use in medical monitoring, but usually this requires a patient to attend a clinic, sit with an experience ultrasound technician, receive the scan, and then book another appointment for a follow-up scan some time later. The process is inconvenient and provides only one snapshot in time of a clinical situation for each scan.

Wearable ultrasound is set to change this, and we have recently covered a few similar devices (see flashbacks below) that can perform ultrasound imaging or drug delivery on the go. This latest device can image to a significant depth (at least for a tiny wearable patch) of 4 cm, allowing tissue monitoring in various clinical scenarios.

“This new wave of wearable ultrasound technology is driving a transformation in the healthcare monitoring field, improving patient outcomes, reducing healthcare costs and promoting the widespread adoption of point-of-care diagnosis,” said Yuxiang Ma, a researcher involved in the study. “As this technology continues to develop, it is likely that we will see even more significant advances in the field of medical imaging and healthcare monitoring.”

The key attribute of the device is its ability to map the mechanical properties of underlying tissues. This has numerous applications, as many medical conditions can lead to changes in tissue stiffness. These include tumor growth, muscle, tendon, and ligament injuries, liver cirrhosis and fibrosis, and changes in arterial wall stiffness leading to myocardial ischemia. Continuously monitoring stiffness in these tissues could permit clinicians to assess disease progression or remission without requiring patients to attend multiple checkups in person.  

“We invented a wearable device that can frequently evaluate the stiffness of human tissue,” said Hongjie Hu, another researcher involved in the project. “In particular, we integrated an array of ultrasound elements into a soft elastomer matrix and used wavy serpentine stretchable electrodes to connect these elements, enabling the device to conform to human skin for serial assessment of tissue stiffness.”

Study in Nature Biomedical Engineering: Stretchable ultrasonic arrays for the three-dimensional mapping of the modulus of deep tissue

Flashbacks: Ultrasound Sticker for 48 Hours of Imaging; Tiny Patch for Cardiac Ultrasound Imaging; Automated Wearable Breast Ultrasound System: Interview with Maryam Ziaei, CEO of iSono Health

Via: UCSD

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