Engineers at the University of California San Diego have developed a wearable ultrasound patch that can offer continuous, non-invasive monitoring of blood flow in the brain. The soft and stretchy patch can be comfortably worn on the temple to provide three-dimensional data on cerebral blood flow—a first in wearable technology.

The team of researchers, led by Sheng Xu, a professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the UC San Diego Jacobs School of Engineering, published their new technology in Nature.

The wearable ultrasound patch marks a significant leap from the current clinical standard, called transcranial Doppler ultrasound. This method requires a trained technician to hold an ultrasound probe against a patient’s head. The process has its downsides, however. It is operator-dependent, so the accuracy of the measurement can vary based on the operator’s skill. It is also impractical for long-term use.