Ultrasound vendors tussle over DEFF data standard

A tug-of-war is brewing between ultrasound vendors Acuson andATL over computer file formats used to store data in ultrasoundimage management systems. At issue is a new ultrasound file formatstandard that could present a challenge to ACR-NEMA's upcomingstandard for vendor connectivity.

ACR-NEMA's digital imaging and communications in medicine (DICOM)version 3.0 standard could be the key to unlocking the connectivityimpasse that has hindered development of multivendor picture archivingand communications systems. DICOM was highlighted with much fanfareat last year's Radiological Society of North America meeting (SCAN12/30/92).

DICOM has been a long time in the making and is not expectedto be completed until later this year. In the meantime, medicalimaging vendors and customers continue to grapple with connectivityproblems.

Those problems are particularly acute in ultrasound as themodality moves from on-board multiformat cameras to networkedlaser printers. Users are discovering that connecting scannersfrom different vendors to a single printer is no picnic. DICOMcould solve such difficulties, but early work in the ACR-NEMAforum did not include file format standards, leaving ultrasoundproponents feeling neglected.

Into the void moved the data exchange file format, or DEFF.DEFF is an ultrasound-specific file format for transferring imagesbetween devices. DEFF was developed by a forum of scanner vendorsled by ATL of Bothell, WA, and Hewlett-Packard Medical ProductsGroup of Andover, MA. A number of peripheral device vendors havestated that they will support DEFF by writing software that enablestheir equipment to accept DEFF-based images (SCAN 4/7/93).

DEFF's proponents claim that the standard will provide a bridgeto ultrasound connectivity until DICOM arrives. Other vendors,however, say DEFF is an ad hoc standard that is confusing themarket. If DEFF is adopted on a widespread basis, it could undermineDICOM when that standard is approved, the argument goes.

The debate has gained added importance due to the product developmentplans of Mountain View, CA-based Acuson and ATL. Acuson's Aegisand ATL's Digital Laboratory are sophisticated image managementsystems that promise to dramatically improve ultrasound imagehandling. Each vendor claims that its system will offer open architecturethat will link scanners from multiple vendors, as well as providea path to DICOM when that standard arrives.

Acuson unveiled Aegis last year (SCAN 10/21/93). It is an AppleMacintosh-based system that relies on a video-frame grabber todigitize images. Aegis uses Apple's QuickTime multimedia datastandard, which will port to DICOM.

ATL IS HARD ON ACUSON'S TAIL with Digital Laboratory. When usedwith ATL's Ultramark 9 HDI scanner, the works-in-progress systemwill give users the ability to stay digital throughout the imagemanagement chain without the degradation that the company claimscan result from analog-to-digital conversion.

Images acquired with Ultramark 9 HDI are stored to ATL's digitalacquisition analysis storage and retrieval (DAASR) module, anoptical disk device that uses the DEFF standard. Images can thenbe transferred to the Digital Laboratory via optical disks.

The use of DEFF as a file format could have limitations onceDICOM arrives, however. Ultrasound departments using DEFF couldhave compatibility problems if the rest of radiology is runningwith DICOM. Archived DEFF images could also require special softwareto be retrieved by DICOM image management systems.

In addition, widespread commercial adoption of DEFF could leadto the establishment of multiple standards, a situation that couldimpede vendor connectivity, according to Lloyd Kreuzer, managerof the Aegis program.

"If all you want to look at (DEFF) for is a way of doingprinting, yes, it works," Kreuzer said. "But if youwant to look in the broader context of where electronic managementis going to go and the fact that you really want to adhere tocomputer standards, then it's not a particularly good format."

DEFF proponents, however, believe these fears are overblown.ATL is participating in the development of the DICOM file formatstandard, and translating DEFF files to DICOM should not presentan obstacle to users, said Lance Hood, product manager at ATL.

"From what we've seen, DICOM is going to be very similarto DEFF," Hood said. "Just as any file format goes throughdifferent revisions as it evolves, I think that the two will endup being identical and there will never be a conflict betweenthe two."

WHAT IS THE STATUS of the DICOM effort? ACR-NEMA earlier thisyear began work on setting a file format standard after promptingfrom ultrasound vendors and cardiologists, who are concerned aboutthe proliferation of different file formats in digital angiographyequipment.

To accommodate file formats, ACR-NEMA added parts 10, 11 and12 to DICOM, according to Dr. Steven Horii, co-chair of the ACR-NEMAcommittee and chair of working group five, which is developingthe sections. Part 10 deals with generic file service, which supportscreating, opening, closing, deleting and other basic file operations.Part 11 will define the profiles of image objects, such as themedium to which an image will be saved. Part 12 specifies howthe medium will connect to part 10.

"DICOM part 10 work is proceeding apace," Horii said."Our intent is to have part 10 out at RSNA. We really wantto let people know about this. There's been a lot of interestin it. It's something people have been asking us about for years."

A draft of the general DICOM standard sans the file formatsections was finalized by the MedPACS section of NEMA last week,according to Horii, and will be sent to ballot to manufacturerslater this month. If approved by a majority of vendors, the standardcould be published in late October. Section 10 could go to ballotlate this year, with parts 11 and 12 early next year.

While the market waits for DICOM, DEFF continues to pick upsteam. In addition to ATL and HP, Acoustic Imaging is supportingthe standard. DEFF recently picked up the ultrasound group ofSiemens Medical Systems as a supporter, according to staff scientistDave Gustafson, who said Siemens plans to support DEFF directlyon the next generation of its Quantum 2000 scanner.

"We're taking the position that we want to support standardsthat evolve, and right now for us DEFF is becoming a de factostandard," Gustafson said. "I think what's going tohappen is that (DEFF and DICOM) will be folded together."

That could be borne out by the work of the MedPACS section,which at its meeting last month approved a vendor proposal toadd a file preamble to part 10 enabling both QuickTime and TIFF(tagged image file format) users to read DICOM files, accordingto Horii. DEFF is based on the TIFF standard.

In a trial run of the proposal, a model DICOM file was readby QuickTime and TIFF users, Horii said. DICOM readability stillneeds to be tested on a wide variety of computers before the conceptcan be assured of working in practice, however. And the compatibilitybetween DEFF and DICOM has yet to be tested, Horii said.

Whatever happens, the ongoing DEFF versus DICOM debate--andthe Acuson versus ATL sideshow--is only confusing the issue ofvendor connectivity, according to Michael Cannavo of Image ManagementConsultants of Winter Park, FL.

"They probably need to sit down in a room together andtalk before they end up confusing a market that's already confusedabout PACS," Cannavo said. "When push comes to shove,DICOM is the standard PACS vendors are supporting. An ultrasoundstandard needs to support DICOM."