Catheter-based ultrasound devices provide a unique view of the interior of vessels and the heart’s anatomy when diagnosing and treating cardiac and vascular diseases. Though already advanced, existing ultrasound catheters can benefit significantly from becoming even smaller, flexible, and being able to look forward, not just to the side.
Researchers at Georgia Tech have developed a tiny chip only 1.4 mm across that integrates a capacitive micromachined ultrasonic transducer (CMUT) with all the necessary electronics. The chip does forward-looking ultrasound imaging and can potentially identify occlusions within vessels as it’s being snaked through on the front of a catheter. Testing on animals is being planned; in the meantime the team tested the device on an ex vivo chicken heart sample and were able to produce 3D ultrasound images at 60 frames per second.
More details about the device according to Georgia Tech:
The single chip device combines capacitive micromachined ultrasonic transducer (CMUT) arrays with front-end CMOS electronics technology to provide three-dimensional intravascular ultrasound (IVUS) and intracardiac echography (ICE) images. The dual-ring array includes 56 ultrasound transmit elements and 48 receive elements. When assembled, the donut-shaped array is just 1.5 millimeters in diameter, with a 430-micron center hole to accommodate a guide wire.
Power-saving circuitry in the array shuts down sensors when they are not needed, allowing the device to operate with just 20 milliwatts of power, reducing the amount of heat generated inside the body. The ultrasound transducers operate at a frequency of 20 megahertz (MHz).
Imaging devices operating within blood vessels can provide higher resolution images than devices used from outside the body because they can operate at higher frequencies. But operating inside blood vessels requires devices that are small and flexible enough to travel through the circulatory system. They must also be able to operate in blood.
Doing that requires a large number of elements to transmit and receive the ultrasound information. Transmitting data from these elements to external processing equipment could require many cable connections, potentially limiting the device’s ability to be threaded inside the body.