Shifting clinical needs recast thick-, thin-client PACS debate

Radiology has been through thick and thin—clients, that is. The two approaches in PACS are defined by the way images are reconstructed, on a central server or a dedicated workstation.

Thick-client products once dominated, but advances in PC technology, particularly in memory, along with smart ways to stream data and an increasingly image-hungry medical community have turned the tables. Now in favor are thin-client products whose servers deliver "screen scrapes" to dozens, even thousands of users on desktop and laptop PCs.

The thick-client systems slipping from vogue work altogether differently. Their images are spawned by algorithms residing on a dedicated workstation, not a central server.

Supporters of thick-client solutions say more can be done on a local workstation than on a distant server. Reading rooms hosting hundreds of interpretations a day need the processing power immediately at hand.

But supporters of thin-client systems contend that the advantages of a distributed network outweigh those of thick clients. Web-enabled processing unites the medical community, reaching the inner sanctum of radiology as well as outpatient imaging, the desks of referring physician desks, and the homes of on-call radiologists.This debate is being argued on the shifting sands of PC technology, which may soon make any conclusion moot, no matter how well reasoned.

Only a few years ago, thick-client systems were a matter of common sense, as dedicated workstations towered over PCs in performance. In recent years, however, standard PCs have evolved to include 2 or 4 gigabytes of RAM and dual- or quadcore CPUs that match or best the power of yesteryear's workstations. Increasingly, companies are making use of both thick- and thin-client technologies.

Siemens Medical Solutions, for example, relies on its thick-client syngo Imaging PACS, using high-power workstations when performing computation-intensive functions. But the company, once entirely in the thick-client camp, now offers a web-enabled technology, its WebSpace product, to reach beyond the radiology department.

"When you are reading hundreds of cases a day—when speed and performance are of the essence—then we would say work with a thick client," said Henri "Rik" Primo, Siemens national director of marketing and strategic relationships. "But if you work remotely and want to read studies from a different hospital from where you usually work or from home, then we would say to use a thin client."

Primo frames WebSpace as a means of distributed processing for small practices, as well as rural and urban community hospitals. But this product, initially intended for teleradiology, has evolved into a cyber-charged miniPACS.

WebSpace can support from three to 20 concurrent sessions from users throughout the hospital network and via secure access from remote locations. It is capable of some fairly sophisticated postprocessing, including Advanced Vessel Analysis, which uses a vessel segmentation algorithm, centerline editing, guided workflow, and automated measurement.

But the most advanced applications, such as volumetric reconstruction of cardiac CT scans, remain beyond the grasp of WebSpace, which, like other thin clients, relies on a central server to do the processing. These would have to be done on the company's thick-client solution set, syngo Suite. The syngo Workflow RIS governs the process from order entry to image and report distribution. The radiology PACS, syngo Imaging, is modular and scalable. Syngo Dynamics is a multimodality dynamic image review, diagnosis, and archiving system for cardiology, general imaging, and ob/gyn. By contrast, the web-enabled syngo WebSpace runs from an office computer, home PC, or laptop.

MEETING CUSTOMER NEEDS

Like Siemens, GE Healthcare depends heavily on thick-client processing to meet customers' IT needs in radiology. Its Centricity PACS evolved out of technologies coming from corporate acquisitions going back nearly a decade. Last year's acquisition of Dynamic Imaging, however, could change that. The PACS developed by this small innovator was widely considered a model in the imaging community for the way thin-client computing should be done.

Dynamic Imaging had focused on community hospitals and outpatient imaging centers. Not surprisingly, GE initially framed its acquisition of the company as an effort to tap the PACS market composed of community hospitals and outpatient imaging centers. But this corporate acquisition could take on a far greater significance. Dynamic Imaging's IntegradWeb fills gaping holes in GE's longtime PACS standard-bearer, Centricity.

"Our main PACS front-end workstation is not web-based," said Don Woodlock, vice president and global general manager of imaging solutions for GE Healthcare. "We had a web add-on called Centricity Web, but this gave referring physicians read-only access to images. The tools and usability available with Dynamic Imaging products are much stronger than what GE had in its portfolio, so putting these two companies together really advances our technology."

The newly acquired web technology could provide an easy-to-use and consistent front end for GE offerings in PACS for radiology as well as the other "-ologies" that GE is targeting, such as cardiology, pathology, and gastroenterology, said Dr. Brandon Savage, chief medical officer for GE Healthcare Integrated IT solutions.

"There is a lot of opportunity to bring the web-based insight at Dynamic Imaging into our broader portfolio," Savage said.

To bring IntegradWeb and Centricity together, the consolidated staff of GE and Dynamic Imaging must fashion interfaces, a process already well developed thanks to work done at sites where both companies' products are in place.

At Stony Brook University in New York, the two products have achieved a high degree of integration, interacting at a level well beyond the simple HL7-based exchange of information that usually characterizes the integration of disparate systems.

Already at the web-enabled end of the spectrum is Philips Healthcare, an adamant proponent of thin-client PACS. Philips, a relative newcomer to the PACS industry, got to where it is much the same way GE did: through corporate acquisition. In 2005, the Dutch company bought PACS developer and vendor Stentor. Philips frames its thin-client distributed network iSite PACS as the cornerstone of future enterprise-wide imaging.

But iSite is more a service than a product. Customers pay a monthly fee based on use of the system to view, distribute, and store medical images. Through iSite, the company can support a virtually unlimited base of users on desktop or mobile computing devices, including personal digital assistants, to access patient data. Using the same distributed network, Philips' XIRIS Radiology Information System complements iSite, said Sybo Dijkstra, senior marketing director for Philips Healthcare Informatics.

"We want to refrain as much as possible from different infrastuctures," Dijkstra said.

Exemplifying the company's use of this distributed approach to reach outward is its Xper IM, designed to handle data coming from cardiac cath, and its Xcelera portal, which provides images and data from key cardiology subspecialties. Philips' IT efforts go beyond imaging into the transmission and archiving of critical care data generated in the intensive care unit, patient and fetal monitors, and wireless products designed to supply patient data at the bedside.

"Our prime infrastructure is highly flexible and scalable, allowing us to add users easily," Dijkstra said.

Critics claim thin-client computing is slower than thick-client workstations. Not iSite, Dijkstra said. The company uses iSyntax, a PACS equivalent to just-in-time data delivery, to present as much-but no more-imaging data as users need. Postprocessed studies, including 3D images, arrive at desktop computers in an instant using mathematical representations of images called wavelets. This "intelligent distribution mechanism" makes optimal use of a hospital's bandwidth, Dijkstra said.

"It keeps pace with demand and shows you the images at the best resolution for that specific environment," he said.

Fujifilm Medical Systems USA was among the first PACS vendors to sign onto the idea of a widely distributed system. The company built its Synapse PACS in a Windows environment, using Internet Explorer to fetch information and advanced visualization tools to perform server-side rendering.

"We invested in a web-based model early, understanding that diagnoses would be done increasingly from remote locations, as radiologists cover multiple facilities," said Bob Cooke, vice president of Fuji's network business management. "Couple this with the overall trend in the computer industry toward web-based technology and what is now possible with consumer-grade technology, and you can see why this makes sense."

ADVANCED VISUALIZATION

Anyone who needs convincing that thin-client computing can do advanced visualization need look no further than TeraRecon. The company years ago introduced the radiology community to advanced thin-client computing through its Aquarius Net, served up as a complement to PACS. But there's more to it.

"People think of us as 'the thin-client company,' but really we're more focused on delivering the optimal clinical experience with the best technology we can get our hands on," said Robert Taylor, president and chief operating officer of TeraRecon.

Just as GE and Siemens have included thin-client technologies in their thick-client approach, TeraRecon has included thick-client technologies in its otherwise thin-client-based products. Technology is just a means to an end, said Taylor, who suggests that the difference between TeraRecon and many competitors has much to do with their relative orientations.

"We built our whole architecture to make the most of thin client when appropriate, while other companies are still stuck with their original workstation roots from a decade ago," he said. "Hence they're mostly thick client, because they have legacy technology that forces them to pursue this architecture. They haven't been able to shake it off, because it's a big deal to rewrite your whole product."

TeraRecon last year built on its thin-client foundation with the release of iNtuition, an architecture that supports the processing, validation, and reading of imaging data. The company is promoting iNtuition as delivering performance equivalent to that of stand-alone dedicated 3D workstations.

The new architecture provides a common back end to the Aquarius thin client, where the computing takes place, and a front end with interfaces that allow access to reconstructed data. The company is positioning iNtuition as a workstation-class thin client, as it provides the means for bringing advanced visualization and clinical application tools to technologists in the scanner control room and radiologists in the reading room, as well as to physicians in their offices and homes. TeraRecon's iNtuition is designed to support workflow as it typically occurs, according to Taylor.

"Look at a CT scan&emdash;the results don't go from the scanner to the person who ordered the scan," he said. "In between, a technologist does some standardized measurements; an interpreting physician, who could be a resident radiologist, looks at the results; and this interpretation is checked by an attending physician. Finally, some representation must be delivered to the referring physician, who may be a surgeon planning therapy or a doctor who wants to sit down with a patient to explain a diagnosis."

Such disparate uses in the context of enterprise-wide demands are forcing PACS vendors to embrace web-based systems that make the best use of available technologies. Agfa's latest PACS, Impax 6, is a blend of thin- and thick-client technologies, according to Lenny Reznik, director of enterprise image and information systems. He points out that the blend between server-side rendering and "smart" client computing depends on customer needs.

On a similar but slightly different tack, Carestream PACS performs server-side rendering but leverages the power of dedicated workstations to handle the needs of heavy clinical users. The PACS offers a unified look and feel regardless of whether operators are at workstations or web-enabled PCs, according to Mike Jackman, Carestream president of healthcare information solutions.

"Our strategy is to have an enterprise imaging approach," he said. "So if you buy a PACS from us, we will give you a back end that can be extended across all -ologies."

In the process, Carestream has turned technological flexibility into a virtue. Customers not interested in making a capital equipment purchase can opt for a Carestream managed service that provides PACS for a fee, an offering not unlike Philips' iSite.

Similar services are popping up in other vendors' portfolios, a transition from capital sales made easier by the need for disaster recovery and offsite archiving services. This need is growing daily with mushrooming volumes of data fed by megaslice CTs, advanced MR, and PET/CT.

Greg Freiherr is business editor of Diagnostic Imaging.