Today, the long-standing, state-of-art ultrasound machines that are pushed around on a cart, with cables and probes, are now replaced in favor of handheld probes that can send images to a mobile phone.
A single probe is not only small but also flexible to image any part of the body, from deep organs to shallow veins, with 3D views. In addition, AI may make these devices operable in any setting by not only trained sonographers in clinics but also untrained professionals.
These devices are developed with silicon ultrasound technology, using a type of microelectromechanical system (MEMS) cramming 4,000 to 9,000 transducers to convert electrical signals into sound waves and back again onto a silicon chip.
MEMS has allowed the production of high-density transducer arrays that can make frequencies in the full 1- to 10-MHz range, supporting imaging of a wide range of depths in the body with one probe. The technology also helped miniaturize components to make everything fit in the handheld probe. Moreover, it is able to pair with the computing power of a smartphone to eliminate the need for a bulky cart.
In 2023, Exo Imaging in Santa Clara, Calif., launched its handheld probe, the Exo Iris. The ultrasound MEMS chips in these probes, at 2 by 3 cm, are also the largest silicon chips that combine electromechanical and electronic functionality.
The probe’s battery is lightweight, lasting for several hours of continuous use when the device is connected to a cellphone or tablet, and has a short charging time. Moreover, the probe’s main chip also performs digitization as well as some signal processing and encoding to make the output data compatible with cell phones and tablets.
These scanners also replicate the quality of traditional imaging and 3D measurements. To provide 3-D information, these handheld probes will take multiple 2D slices of the anatomy and then construct the necessary 3D data through machine learning and AI.
The AI developed for these probes may be possible for professionals untrained in ultrasound. According to a 2022 study in NEJM Evidence, nurse midwives can use portable probes to determine the gestational age of a fetus, with accuracy similar to that of a trained sonographer.
