Researchers at the University of California San Diego created an ultrasound patch that can measure blood flow in vessels as deep as 14 cm within the body. The stretchy patch can be applied to the skin and may help clinicians to monitor and diagnose various conditions, including blockages that could cause an infarct. The patch contains an array of ultrasound transducers that can measure blood flow in vessels directly beneath it and the ultrasound beam can also be steered to assess vessels that are nearby, but not directly below.
Monitoring blood flow in specific vessels can help clinicians to diagnose various cardiovascular diseases. For instance, measuring changes in blood flow in the carotid artery could show that someone is at a risk of stroke, and help to initiate treatment before a stroke occurs. However, current technology to accurately measure blood flow can be inconvenient, invasive, requiring a qualified technician to use an ultrasound probe to investigate the target vessel.
This patch is conceived as a more convenient alternative. “Just stick it on the skin, then read the signals. It’s not operator dependent, and it poses no extra work or burden to the technicians, clinicians or patients,” said Sai Zhou, a researcher involved in the study, via a UCSD press release. “In the future, patients could wear something like this to do point of care or continuous at-home monitoring.”
The flexible device contains a 12 x 12 grid of tiny ultrasound transducers embedded in a stretchy polymer. The transducers can be controlled to activate together, allowing the researchers to investigate vessels that are as deep as 14 cm beneath the skin. In another mode, the transducers will activate at different times, causing the ultrasound beam to be steered, which allows the user to investigate vessels that do not lie directly beneath the patch.
“With the phased array technology, we can manipulate the ultrasound beam in the way that we want,” said Muyang Lin, another researcher involved in the study. “This gives our device multiple capabilities: monitoring central organs as well as blood flow, with high resolution. This would not be possible using just one transducer.”
So far, the researchers have tested the patch and have shown that it is as accurate as a commercial ultrasound device. At present, the device is tethered to wires that provide power, but the research team hopes to develop a wireless version in the future.
Study in Nature Biomedical Engineering: Continuous monitoring of deep-tissue haemodynamics with stretchable ultrasonic phased arrays