Low-cost image distribution method draws attention at infoRAD exhibition

Low-cost image distribution method draws attention at infoRAD exhibition

Approach reduces need for high-end workstations, network bandwidth

Regular attendees at the infoRAD exhibit at the Radiological Society of North America meeting have long enjoyed the look into the future of radiology that its exhibits and poster sessions provide. That futuristic view was evident at the 1998 exhibit, despite an odd global village theme imposed by RSNA conference organizers.

One project in particular was the talk of infoRAD, as well as the RSNA's regular exhibit floor. A University of Pittsburgh team has developed dynamic transfer syntax (DTS), a new protocol for low-cost enterprise-wide image distribution. The technique may obviate the need for expensive high-bandwidth networks and high-powered workstations, researchers say.

The UPMC team, headed up by Dr. Paul Chang, received a summa cum laude award for DTS, a technology development effort that began during planning for a large-scale PACS network. At the time, UPMC officials realized that its $25 million PACS budget would not be sufficient to meet the image-viewing requirements of its referring physicians. Those physicians, particularly medical subspecialists and surgeons, wanted the same exam fidelity and manipulation options available to radiologists.

To learn more about this problem, Chang, director of radiology informatics, and his PACS team further researched the needs of the referring physicians. They determined that in roughly 60% of cases, a timely radiology report alone met their colleagues' needs. In 80% of the cases, the report with a subsampled image (as typically distributed by a Web server) would be adequate. But in 20% of the cases, clinicians wanted to be able to review patient exams with the same resolution and display capability as radiologists. This need was especially acute in cases where positive findings were reported. Furthermore, they wanted immediate access to any and all archived exams for that patient. Without these abilities, the referring physicians wanted film.

To solve these problems without deploying massive quantities of data over huge network pipelines to $100,000 workstations, Chang and his colleagues developed DTS, a wavelet-based flexible representational data scheme. With DTS, image data are sent to the requesting workstation in a manner that fits the requirements of the user as well as the resources of the network and viewing workstation. Wavelet schemes allow additional image detail to be delivered when needed by the user.

When an image request is made, DTS determines how many images and at what resolution to transmit after assessing the resources available at the workstation. When a user logs on and opens an exam for review, DTS evaluates what type of workstation is being used for delivery of information, as well as the number and resolution of monitors.

For example, a clinical review workstation, consisting of an average PC and a 1K monitor, might initially receive a limited number of exams in a large exam set, subsampled at 1K resolution. Higher resolution is then delivered as a user magnifies or zooms in on an image, or when the user moves on to display the remainder of the images in the exam. This real-time image delivery enables the use of less powerful networks, such as Ethernet, and allows all display workstations to have the same features and functionality as an expensive diagnostic workstation, according to the researchers.

With DTS, images do not require extensive autorouting, and can be accessed in less than two seconds, Chang said. In addition to lower bandwidth network requirements, the number of expensive, dedicated PACS workstations can be curtailed. This considerably lowers the cost of implementing enterprise-wide PACS, he said.

DTS is being commercialized through Stentor, a San Francisco startup supported by venture capital and an equity stake from the University of Pittsburgh. Headed by former Imation Cemax-Icon vice president of sales and marketing Oran Muduroglu, Stentor hopes to license the technology to PACS and HIS vendors, as well as any other healthcare image information systems. Other image-oriented industries outside of healthcare will also be targeted.

Other key executives at Stentor include chief technical officer John Huffman, former medical marketing manager for Silicon Graphics and co-founder of wavelet compression firm Aware. Chang, though not a Stentor employee, serves as the company's executive clinical advisor.

Stentor hopes to bring DTS to market in the third quarter of 1999, Muduroglu said. Actual commercial applications through OEMs could be shown as soon as the 1999 RSNA meeting, with product delivery in 2000, he said. The company is in discussions with five OEMs about incorporating DTS into their product lines, he said.

In other notable infoRAD exhibits, representatives from Northwestern University Medical Center in Chicago presented a customized software program that enables a medical center to determine the bandwidth, architecture, and design requirements for a PACS network. The U.S. Army and Air Force also discussed developments in their goal to create a virtual radiology environment (PNN 6/98).

--by Cynthia E. Keen

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