Ultrasound image format could boost connectivity

The growing trend toward ultrasound networking promises hospitalsimproved flexibility and efficiency. But unless connectivity problemsare resolved, having equipment from different ultrasound vendorstalk to each other will be like building a Tower of Babel.

Conquering the connectivity impasse is the goal of the dataexchange file format (DEFF). DEFF was the talk of the exhibitfloor at last month's American Institute of Ultrasound in Medicinemeeting in Hawaii.

DEFF promises to make life easier for both manufacturers andpurchasers of ultrasound scanners and peripherals by creatinga standardized computer file format for transferring ultrasoundimages between devices.

The growth of digital-based peripherals such as workstationsand laser cameras has led to the need for a digital interfacelike DEFF, according to David J. Thomas, director of advanceddevelopment for Acoustic Imaging of Phoenix.

Most current interfaces are video-based. Digital images areconverted to analog form and sent by video output to a peripheraldevice. Eventually, they can be converted back to digital formfor archiving or digital printing.

Digital interface advocates maintain that such back-and-forthconversion results in image degradation that could be avoidedby keeping the entire process digital. Until DEFF, however, nostandard for connecting equipment from different manufacturersexisted.

"If we didn't have an agreed-upon DEFF specification,(peripheral vendors) would have to put software into their machinesthat would allow them to convert an image from every differentultrasound company," Thomas said. "If you supported10 ultrasound companies, you would have to provide conversionutilities for 10 different ultrasound formats."

Acoustic Imaging is one of a number of scanner and peripheralvendors that have signed on to the DEFF standard. Other manufacturersinvolved in a DEFF forum held at Aspect last summer include ATL,Hewlett-Packard, Aspect Electronics, 3M, Agfa, Kodak, Konica andPolaroid (SCAN 3/24/93).

ONE NOTABLE EXCEPTION to the companies backing DEFF is Acuson.The Mountain View, CA-based vendor recently released Aegis, itsown image management and networking system (SCAN 10/21/92 and12/2/92).

Aegis frame grabs images from Acuson and other vendor systems.But Acuson's greater ability to link with its own scanners enablesAegis to transfer patient data and color-flow Doppler as wellas gray-scale images to a workstation, reproducing the functionalityof the original scanner.

Analog-to-digital conversion technology has evolved to thepoint where data are not lost in the conversion process, accordingto Samuel H. Maslak, Acuson president and CEO. Maslak discussedthe frame-grabbing issue with SCAN when Aegis was introduced lastOctober.

"The main reason you might want to do it (direct digitalconnections) would be if you could get better performance,"Maslak said. "That has to do with whether or not informationis lost in conversion from digital to analog and back to digitalagain. The answer to that question 10 years ago was that you definitelylost information. You don't lose information now."

The cost of high-performance digital-to-analog and analog-to-digitalconverters is low, and their accuracy and sampling rates are high,he said.

Siemens Quantum has joined Acuson in backing away from theforum. Diasonics has indicated that it will probably support aDEFF standard.

Although the concept of DEFF is unique, perhaps as noteworthyis the fact that vendors usually in cutthroat competition witheach other were able to set aside their differences long enoughto develop an open standard.

Vendor collaboration was facilitated by Aspect Electronics,which supplies ultrasound monitors and multiformat cameras tomanufacturers (see story, page 2). Aspect's management recognizedthe need for DEFF and believed that their company was in a positionto bring the idea to fruition.

"We felt that we were a good neutral party that vendorscould work through because we sell to everyone in the industryin the U.S.," said Don Roelands, Aspect's corporate developmentmanager.

Various companies working independently on file formats exchangeddata with each other through Aspect. They discovered that ATLand Hewlett-Packard had made the most progress, so the two companiesconsolidated their efforts to create DEFF.

DEFF is based on an image storage format already in use inthe computer industry, tagged image file format (TIFF). DEFF isTIFF-compatible, and DEFF files can be read with TIFF-based softwaresuch as desktop publishing programs.

ATL has moved quickly to integrate DEFF into its existing lineof products. The Bothell, WA-based company has developed an opticaldisk storage device that will be mounted on ATL's Ultramark 9HDI scanner. ATL is also incorporating DEFF into its Digital Laboratoryimage archiving and management system that is under development,according to John Bono, advanced systems engineering manager forATL.

Although optical disk storage is the most concrete applicationfor DEFF, the standard has potential applications for linkingother networked peripherals as well.

For instance, Acoustic Imaging is pushing to have the DEFFstandard developed for networks, according to Thomas.

"We want to see the ability to send an image over a hard-wireto some other device," Thomas said. "The image willbe transferred and that other device will be able to read it becauseit understands the DEFF specification."

This could pit DEFF against the ACR-NEMA's digital imagingand communications in medicine (DICOM) version 3.0 standard fornetwork connectivity, however (SCAN 12/30/92).

As developed, DEFF is not DICOM-compatible. Indeed, part ofthe impetus for developing DEFF came from the lack of supportfor ultrasound in the DICOM specifications, according to Thomas.

DEFF can be seen as an interim step until DICOM becomes reality,Roelands said.

"What we're doing is trying to stop the proliferationof 50 more formats," Roelands said. "Right now everybodyhas a different format. If we can hold it to one until DICOM finishes,I don't see that as a deterrent, I see that as a benefit."