Medical Imaging Tests Storage Capacity

Joseph Goedert, News Editor
Health Data Management Magazine, November 1, 2008

Wichita

Clinic PA, a multi-specialty practice with 160 physicians, has a wide range of diagnostic imaging modalities throughout its 12 south-central Kansas sites.

It has a picture archiving and communications system from Richfield Park, N.J.-based Agfa Healthcare, and the usual short-term, archive and off-site backup storage systems.

This fall, however, the clinic is installing Agfa's Impax Data Center, which has the capability to also store non-radiology diagnostic test results such as video or images.

That means, by mid-December, physicians will have immediate, digital access to Holter monitor readings, EKG traces, pulmonary function results and surgical scope procedures. And the "radiology" tab in the clinic's electronic health records system that gives quick access to diagnostic images will change to a "diagnostic testing/images" tab. "It's no longer just about radiology, it's diagnostic imaging and diagnostic testing," says Larry Leopold, manager of radiology. Over time, these newly stored images and videos will add to the diagnostic imaging storage needs of the clinic. Those needs have been growing rapidly the past two years since adding digital mammography, and echocardiograms are coming on board soon.

But as the volume of stored images at Wichita Clinic and other provider organizations increases with more adoption of digital diagnostic systems, disk drives to store images keep getting better and increasingly faster, Leopold says. "This year, we may need five drives and next year two-and-a half. It's amazing what they're doing in information technology storage."

According to organizations that have digitized their radiology departments, diagnostic imaging storage strategies are not particularly complex. Storage is cheap and when you need more, you buy it and install it. "Storage is probably one of the lower concerning items in my budget," observes Shawn Weise, who serves as an application development manager at Methodist Health System in Omaha, Neb.

But digital imaging systems-think 64- or 256-slice CT scanners-can eat up a whole lot of disk space in a short period of time. So, basic, well-followed policies for monitoring capacity are warranted. A number of issues figure into the equation. Raised expectations among physicians about quick access to images are among them. Another is the expected shelf life of images. Storage vendor longevity and future technologies also play a role as hospitals wrestle with a long-term storage strategy.

Constant Expansion

Monitoring diagnostic imaging storage capacity-and adding to it-is a continuing process when operating in a digital radiology environment.

Methodist Health System in 2004 implemented a picture archiving and communications system from Cerner Corp., Kansas City, Mo. The two-hospital delivery system, with a third facility opening in 2009, started with six terabytes of storage. It now has 20 TB and is looking to expand that to 30.

"Our growth is about a half-terabyte a month," Weise says. "We do projected growth for a year then monitor monthly. When about 15% capacity is left, that's when we want to start an expansion."

Methodist Health could complete a storage expansion in a month if necessary, but the process generally takes two or three months.

The most challenging part of an expansion, Weise says, is making sure the new disks, which are constantly improving, will work with older ones. "With larger capacity disks, you really have to walk through the firmware code to make sure they are compatible with existing disks." Firmware coding covers the application drivers that support hardware components being introduced in an expansion or upgrade.

To keep images available during maintenance or for any other type of downtime, some organizations create dual-storage systems.

But others, like Methodist Health have found that cost-prohibitive and have turned to alternatives. "We have a mini-PACS with a 90-day storage capacity to get up quicker," Weise explains. "In 10 or 15 minutes, we can have doctors working off the smaller system." The mini-PACS is from a third-party vendor running off a separate database, and Methodist Health has not been pleased with the level of vendor support. The delivery system soon will implement a mini-PACs from Cerner.

The speed at which storage systems can present medical images and related reports to a reading workstation are breathless. Physicians have grown to expect sub-second response when they are working in an electronic health records system, and they now expect it when they pull up huge image files.

That's one reason why, in early 2009, Methodist Health will replace its existing reading workstations, which have not performed well with larger data sets. "Images are not being presented in a timely fashion," Weise says. "If we don't present it fast, you can assume that affects patient care."

And Weise has another idea for improving care for all organizations using digital radiology. He'd like to see regional health information organizations for medical imaging to reduce redundant tests and storage requirements of individual organizations.

Rapid Improvement

Recent upgrades at Centra Health in Lynchburg, Va., further demonstrate improvements of imaging storage systems in recent years.

Centra Health used to have nine servers to provide short-term storage of diagnostic medical images from a variety of modalities. Spanning three hospitals and an outpatient imaging center, the delivery system updated its picture archiving and communication system in March and swapped out servers, as well.

With the upgrade, Centra Health this summer had four servers to serve all modalities, including two 64-slice CT scanners. It expected to add another server this fall-when a hospital jointly owned with another organization comes on line with digital imaging, including a 4-slice CT.

"Servers are more robust than they were in 2003 when we started," says Randall Shortt, radiology information systems coordinator. "Like all servers, they got smaller and better." And, he adds, the cost of servers hasn't changed much in the past five years.

How good are servers today? One short-term server can easily handle two 64-slice CT scanners, Shortt says. Centra Health, however, puts its servers in a round-robin configuration where images go where storage is available.

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