Esaote allies with start-up to take ultrasound into silicon era

Italian imaging systems manufacturer Esaote is planning a radical change in the way its ultrasound scanners handle acoustic information. The Genoa-headquartered company, part of the Bracco group, is preparing to swap a high-tech silicon-based transducer for its conventional ceramic-based technology. The move, scheduled to start in spring 2006, could make Esaote the first ultrasound manufacturer to abandon the decades-old method of converting acoustic waves into images with piezoelectric crystals.

"We'll be using this technology to deliver better performance to our customers," said Fabrizio Landi, general manager of Esaote.

All medical ultrasound transducers on the market are fitted with crystals that create high-frequency sound waves when an electric voltage is applied. They vibrate again when ultrasound waves echo back from tissue. The alternative approach switches the ceramic crystals for tiny silicon structures known as capacitive microfabricated ultrasonic transducers. The drum-shaped transducers, each no wider than a human hair, vibrate when sending and receiving ultrasound waves.

Esaote will get its novel transducers from Sensant, which has focused on the development and commercialization of silicon ultrasound technology since its formation in 1998. Prior to striking a deal with Sensant, Esaote had been investigating silicon solutions itself.

"We have been looking into this technology for five years as an alternative to the conventional method of processing ultrasound waves," Landi said. "We found Sensant at just the right time, and we are pretty enthusiastic about the preliminary results."

Sensant, based in San Leandro, CA, expects silicon-based probes to deliver better acoustic response. This should translate to enhanced visualization of tissue boundaries or tumor edges and improved resolution of axial images, according to Andrew Cittadine, vice president of marketing for Sensant.

The company is currently building devices that mimic 2D piezoelectric probes for ultrasound imaging. The technology's real potential, however, may lie in real-time 3D applications.

"The first important step, however, is to make a product that is compatible with today's (2D-oriented) systems," Cittadine said.

Cittadine predicts that 3D ultrasound will gain popularity because of workflow advantages. A system that can capture a complete volume of information means faster scans. A 3D image can also aid initial rapid diagnosis, even if radiologists then slice the volume and provide a final assessment from 2D images.

Volumetric ultrasound has been slow to catch on. But that will change, he predicted.

"I think 3D may follow the same path as color Doppler imaging," Cittadine said. "When it first came out, it was seen as an interesting tool. Then people found more and more clinical applications for it."

An all-silicon probe provides the foundation for merging transducers and circuitry on a single silicon wafer. This should lead to more compact ultrasound systems, Landi said.

"Maybe in the future you would only have a probe connected to a PC," he said.

Esaote expects to receive its first batch of commercial probes from Sensant later this year. The company plans to start commercial sales of systems incorporating the probes in spring 2006, subject to regulatory approval.

The silicon transducers will initially be sold only with Esaote's premium-end products, owing to its higher cost of development and production. If the technology takes off and costs fall, it could be rolled out to the entire range.

"As with many things in their infancy, this new technology will not be the least expensive," Landi said. "But it is potentially very cost-competitive in the medium to long term."