AI hopes 3-D unit will burnish technical image

Acoustic Imaging hopes the upcoming commercial release of its3-D ultrasound workstation will stake a renewed claim for thevendor as a leader in ultrasound innovation. The Dornier subsidiaryimpressed users with its high-frequency gray-scale scanner introducedfour years ago (SCAN 11/9/88).

AI's reputation suffered, however, due to delays in developinga color-flow Doppler ultrasound system. The Phoenix firm begandeliveries of its first color system, the AI 5200S, in August(SCAN 8/26/92).

For its first color-flow offering, AI had initially plannedto introduce a super-high-end scanner based on a sophisticatedmaximum-entropy method (MEM) algorithm (SCAN 12/12/90). The companyoverestimated the scope of the project, however, which took longerto develop than anticipated. AI subsequently changed its marketingstrategy, opting for a two-pronged color-flow line by releasingthe standard system this year and the more advanced MEM systemin 1993.

The delay in bringing a color-flow system to market had aneffect on AI's image in the industry, according to vice presidentof sales and marketing William J. Doherty.

"We were looked at as a company that had extremely goodimage quality," Doherty told SCAN. "We tried to makethat same jump with color. We went two generations ahead withwhat we were doing with that technology. It created a large gapfrom when we should have had color to when we ultimately broughtit out."

But AI's new 3-D workstation should erase any doubts aboutAI's ability to innovate, he said.

The system uses a unique 3-D transducer with an internal motorthat swivels the scanhead to acquire 2-D slices. The swivelingscanhead eliminates the need for the user to move the transducer,thus reducing the number of artifacts and the acquisition of redundantslices, according to the company.

Slices acquired by the transducer are captured to digital formby a video frame-grabber and transferred to the 3-D workstation,which is a PC-based dual-processor system using Intel's 80486and I860 processors. The images are transferred into a Cartesian3-D coordinate system. It takes about five minutes for the computerto reconstruct the images. AI's engineers are working to reducethe reconstruction time, with the goal of getting as close toreal-time 3-D as possible.

Because of the dual processors, users can continue scanningor performing other operations while the image is reconstructing.Only one 3-D reconstruction can be performed at a time, however.

A unique aspect of the system is its use of a "look-through"algorithm that takes advantage of the gray-scale information acquiredby ultrasound to produce transparent 3-D reconstructions.

Transparent reconstructions allow users to see the surfaceof an object as well as its internal structure, such as a kidneystone inside a kidney. Three-D reconstructions of CT and MRI scansshow only surface volumes, and users must peel layers off thereconstructed image to visualize internal structure.

The workstation's ability to provide transparent images ismore practical than surface rendering and could be valuable inclinical applications such as surgical planning, according toPascal Roncalez, AI's worldwide product manager.

"The user can look through the tissue and see the objectof interest," Roncalez. "It looks like an ice cube ina glass of water."

For the most part, AI is remaining mum about clinical applicationsfor the system, preferring to await results from the four testsites to which the workstation has been sent. One possible applicationcould be for early detection of fetal malformations such as spinabifida.

AI filed a 510(k) application for the system in July.

AI's early jump in 3-D ultrasound is already having a positiveimpact on the company's marketing, according to Doherty. Not onlydoes the product improve AI's technological reputation, but itis a good selling point to clinicians interested in buying a scannerthat will be 3-D-capable in the near future. The workstation iscompatible with all of AI's scanners.

"It's been a tremendous door-opener for us," Dohertysaid. "It's given people the opportunity to look at us ina different light."