Tech & Innovation in Healthcare

Measuring 3 mm thick, the flat chip is roughly the size of a postage stamp, but rigid enough to capture images while the patient continues their regular daily activities. Other researchers have attempted to produce flexible stick-on ultrasound patches in the past, but the thin form factor led to reduced image quality due to the lower number of transducers in the patches.

The transducers of the MIT team’s patch capture images with incredible resolution for a small form factor. “The lateral and axial resolutions of the BAUS patch were shown to reach up to 192.4 μm and 380 μm, respectively,” says Philip Tan, PhD student in the department of electrical and computer engineering at the University of Texas at Austin.

Comfortably Capture Images for 48 Hours

Sonographers apply a thin layer of gel to the patient’s body to move a traditional ultrasound probe easily over a targeted area. This gel evaporates over time, which makes the gel an unlikely candidate for use with this small-size probe. Instead, researchers developed a new hybrid material that lasts throughout the duration of the long-term ultrasound studies.

“The material consists of a tough hydrogel encapsulated by an elastomer. The elastomer prevents the hydrogel from dehydrating while still allowing the coupling layer to be soft, have robust adhesion, and provide good transmission of the ultrasonic energy between device and tissue,” Tan says. The hydrogel coupling layer’s soft feel helps the patient remain comfortable while wearing the rigid probe.

The thin elastomer membrane proved to “show that the bioadhesive layer can robustly adhere the BAUS device on the skin over 48 hours in dry and wet environments,” researchers wrote. However, while the adhesive provides a strong hold, the BAUS device easily detaches from the patient’s skin simply by peeling up one corner — and no residue is left behind once the probe is completely removed.

Evaluate the Heart Outside of the Imaging Suite

At different frequencies, researchers can view different body structures at different depths. For example, a 10 MHz frequency allows the probe to image areas 2 cm under the skin, such as blood vessels and muscles. Researchers can view internal organs 6 cm deep, such as the chambers of the patient’s heart when using the probe at a low frequency like 3 MHz.

The small size and remarkable imaging power of the ultrasound sticker would allow healthcare providers to efficiently monitor a patient’s condition while the patient goes about their daily life.

Three areas where the ultrasound sticker would be a welcome diagnostic tool include:

Cardiovascular: A physician may affix an ultrasound sticker to a patient who has an arrhythmia. The patch could monitor the patient’s heartbeat and alert the patient and their physician when an irregular heartbeat is detected.

Infections: A patient contracts COVID-19 and becomes symptomatic. The provider could apply the ultrasound sticker or multiple stickers over the patient’s lungs to continuously monitor the patient while they’re at home. After wearing the stickers for 48 hours, the patient would return to their doctor’s office where the results of the ultrasound device would be reviewed for possible signs of damage to the patient’s lungs.

Oncology: Physicians could place an ultrasound patch on a patient diagnosed with a tumor. The physicians could then use the patch to image the tumor over time to evaluate if the malignancy is growing.

By being able to continuously image a patient’s body structures, providers can receive an accurate picture of what is occurring with the patient outside of an examination room or imaging suite.

Looking Ahead to Future Models

Currently, the ultrasound sticker has limited connectivity options. Providers need to physically connect the device into the external Verasonics Vantage system to collect and review the data the device records. The BAUS patch’s current plug-and-play interface would allow the device to “find immediate applications in nonmobile imaging in clinical settings, such as long-term imaging of patients in intensive-care units,” the researchers wrote.

Researchers plan to enhance the capabilities of the device by outfitting it with a wireless data-transmission system and a miniaturized power source. This goal is achievable as electronic components continue to shrink and production methods allow manufacturers to combine the necessary components into one small-sized imaging device.