While imaging workstations are still sprinkled throughout hospitals and radiology departments, vendors are increasingly offering thin client solutions to radiologists that give them?and their referring physicians?sophisticated 3D reconstruction tools from any computer.

When it comes to 64-slice CTs, radiologists depend on powerful workstations with their expensive microprocessors and memory to slice, dice, and render all of the imaging data into crisp, lifelike, 3D photos of the heart, arteries, and more.

But a workstation cannot be carried under the arm to every referring physician who wants to have a closer look at those 3D images. Yet surgeons, emergency department physicians, and others find 3D image rendering valuable as well.

To make 3D image processing more accessible—and affordable—throughout the hospital enterprise, PACS companies and their 3D rendering partners are increasingly turning to “thin client” solutions. Thin client generally uses a separate, central server with a Web portal to allow users with as little as an iPhone to see 3D studies from anywhere, at any time. Thin client technology has been around for a few years, but if trends continue, having imaging workstations sprinkled around the hospital may one day become as scarce as light boxes.

Defining Thin

Thin client technology is nothing new in the information technology world. Many industries rely on computer workstations with expensive, sophisticated, microprocessing chips and other hardware to design products with 3D images. Each team member designing a car or a computer game, for example, needs access to those 3D images, and therefore, needs an expensive workstation to contribute their part.

Essentially, a thin client solution takes the graphics processing power and software of a single workstation and transfers it to a central server. Authorized users can access the server with a conventional PC or laptop through a Web portal, allowing many team members to simultaneously use that power.

Applied to radiology, thin client solutions allow radiologists to more easily share 3D coronary CTA images, for example, with referring physicians—and their patients. Using their laptop, a surgeon may use a thin client Web portal to plan an operation at home, or use the same 3D views on his office laptop to explain the operation to the patient.

Pedro Diaz, PhD, vice chairman of imaging and informatics systems in the department of radiology at Metro Health Medical Center in Cleveland, uses a thin client solution from Philips Healthcare, Andover, Mass.

“Like Google Maps, [the thin client server] does all of the processing for you that you ask it to do, interactively, and in real time, and then it sends your PC the actual rendered image of just, say, Florida, and not the entire planet,” Diaz said. “So, that saves on bandwidth, saves on deployment, and more importantly, we can run it anywhere.”

The Advantages of Going Thin

There are several advantages to thin client solutions over the traditional workstation model of 3D rendering:

  • Like workstations, thin client allows users to access advanced imaging tools, such as bone removal and automated vessel analysis, but only needs conventional PC technology and an Internet or Ethernet connection.
  • Radiologists and referring physicians are not tied down to a particular area’s workstation, which may be in high demand by radiologists and other physicians.
  • Instead of scrolling through the static images of a traditional DICOM viewer, referring physicians, surgeons, and off-site radiologists can use thin client’s advanced postprocessing applications, 24/7, in their offices, in operating rooms, or in emergency departments.
  • The hospital’s network no longer has to carry huge CT data sets to multiple workstations. Rather, the data is transferred to the thin client server, which can process and send smaller, relevant packets of data to multiple users, saving bandwidth.
  • Prior CT exams can be retrieved into the thin client server as well.
  • In general, a thin client system is much less expensive than purchasing—and maintaining—multiple workstations, which can cost $50,000 each.

Gary J. Wendt, MD, enterprise director of medical imaging at University of Wisconsin Hospital, Madison’s (UWM’s) department of radiology, said, “It basically does all of the heavy lifting, so that the graphics processing can be done in the server room on a GPU rendering mode, rather than having multiple, heavy-duty clients everywhere.”

“You shouldn’t underestimate the economic advantage of thin client,” said Peter Kingma, vice president, CT Division for Siemens, Malvern, Pa. “One server can drive a relatively modest outlay in technology, which will give you full-blown workstation performance without the full-blown workstation cost.”

In terms of thin client’s flexibility, a referring physician could even view a 3D rendering of a coronary CTA study on an iPhone.

“You could, in principle, use a PDA right now,” Kingma said. “The only limitations you have is that you’re going to have some functionality limitations based on the bandwidth of the network that supplies such PDAs.”

CT and Beyond

Thin client is most effective and cost-effective for CT because of the huge amounts of data that CT generates to be processed and rendered. Radiology’s other workhorse modalities could be incorporated into some systems, but the benefits are limited.

“MR, ultrasound, and other modalities are a little more difficult [with thin client], particularly MR, because different tissues may end up with a different intensity value in the study itself,” said Colin J. Holmes, PhD, director of strategic account development, Calgary Scientific Inc, Alberta, Canada. “It’s harder to selectively remove them in the segmentation paradigm, and more difficult to color them the same or differently, or to give them a lifelike appearance.”

However, Diaz said that Metro Health has sent MR exams and x-rays to their thin client portal, mainly for teleradiology purposes. “We’re an academic center, so we tend to push the envelope a little. We send the portal MR, plain chest x-rays, ultrasound scans, pretty much anything, because we quickly discovered that it would accept it and display. So, even though we don’t do 3D processing on a chest x-ray, it’s sometimes useful to have that for teleradiology applications, for [physicians] to take a quick look.”

John F. Phelps, CT product manager of Siemens CT division, does foresee thin client expanding its reach, however. “In the current iteration, we can currently do CT and a little bit of MR via a certain application, but the larger goal is more of a multimodality, like on our workstation,” he said.

The Downside of Thin—for Now

Despite the potential flexibility, processing power, and cost savings, workstations still dominate the market for several reasons.

Although UWM has been using Minneapolis-based Vital Images Inc’s ViTALConnect solution thin client product for 2 years, the hospital has yet to trade in its traditional Vital Images workstations.

“We still use a mix of thick and thin,” Wendt said. “At the current time, there is still some functionality between what the thick client offers and what the thin client offers. That’s really true throughout most of the 3D world. The most advanced functionality, like some of the advanced volume analysis, and advanced functionality such as perfusion, you still can’t do that on thin.”

While thin client solutions are very effective, they are not a one-to-one replacement for workstations—at least not yet.

Workstations have been around for many years. Radiologists are used to them, and the previously mentioned advantages of thin client are not as compelling for all institutions, such as the outpatient imaging market, which may need only a handful of dependable and familiar workstations.

Plus, thin client is still relatively new technology, and no one is going to throw out a recently purchased $50,000 workstation. Workstation vendors will still be servicing and upgrading them for years to come. More likely, hospitals will gradually avail thin client to referring physicians.

Thin client image quality may still be slightly compromised. “One of the drawbacks from a diagnostic radiology point of view is that it’s harder to move diagnostic-grade images than it is to move 8-bit images through the prospective video screen,” Holmes said. “The farther you get away from the central location, the worse, in general, that the network connections are, and the more you have to breach the technology with such things as image compression in order to get the performance that you require for interactions.”

Holmes also pointed out that it is up to the radiologist or whoever is looking at the image set to be using the appropriate monitor for the task. It is obviously one thing to educate a patient about a procedure on an office laptop. It is another thing—and against American College of Radiology guidelines—to be doing a final report on a laptop.

Diaz agreed, but added: “For CT and MR interpretations, you do want to pay attention to the quality of the monitor that you’re using, but you don’t necessarily need to go to a $20,000 monitor, either. It’s good enough so that you can provide an accurate interpretation.”

Although thin client solutions can still render 3D and perform other advanced visualization features, in general, the workstation will have more whistles and bells—although that will not be the case forever.

“If you were to look today at what vendors have achieved in terms of thin client versus a dedicated workstation, I would say that the classic manifestation of thin client does not yet equal the functionality depth that you can achieve on a workstation,” Kingma said. “That’s simply because the complexity is still something that various vendors are working through to translate their functionality on a workstation to this thin client environment. But it’s really just an investment in time and man-hours, and eventually there will be, in principle, no theoretical performance difference between the two.”

Similarly, although workstation vendors have tried to design their thin client user interfaces to be as close to their workstation’s keystrokes, clicks, toolbars, etc, that is often not the case. Consequently, there may be a learning curve on thin client, which means retraining physicians to use the new interface. Software designers are certainly working on making their products seamless with their workstation applications, but once again, it is a matter of time and manpower.

The Future of Thin

As with the trend in RIS/PACS integration, 3D vendors are beginning to partner and integrate their rendering software with a particular PACS product—if not their own.

A product that is designed for a particular PACS is going to be able to offer more powerful features and improve workflow, while providing rich 3D capabilities.

One example of this trend is Calgary Scientific partnering with Los Angeles-based PACS company Intuitive Imaging Informatics to create a thin client solution called ResolutionMD, a product designed exclusively for Intuitive Imaging’s PACS product.

Siemens also is working toward more integration. “Siemens is a company that produces both PACS and workstations and thin client, and so we see a closer and closer marriage of these technologies,” Kingma said.

It remains to be seen how soon hospitals—and vendors—fully adopt thin client servers in lieu of workstations.

“There will always be people who want workstations: Small facilities, single scanners, off-site imaging centers,” Diaz said. “But my guess is that over the next 2 years or so, you’re going to see more people buying more thin client server packages than workstations. It will be a 1-to-3-year process, where that crossover happens, and it will probably happen fairly exponentially when it does.”

Tor Valenza is a staff writer for Medical Imaging. For more information, contact .