Byline: Joseph Goedert, News Editor
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.
Another example of improvements: The University of Virginia Health System in Charlottesville in late 2005 went live on new long-term storage systems from EMC Corp., Hopkinton, Mass. The disks with total storage capacity of 27 terabytes of data filled an entire rack.
Less than two-and-a-half years later, the delivery system added another 27 terabytes of storage, which filled one-quarter of the space and cost 50% less, says Sean Moynihan, director of radiology information systems.
Building Out
Centra Health generates about three terabytes of imaging data a year, and has 12 terabytes stored out of a capacity of 16 terabytes. In 2009, the delivery system will implement digital mammography. Shortt hasn't yet determined the number of terabytes of long-term archive storage the system will need, but expanding capacity isn't a challenge. He'll just add some FastT archive disks from Armonk, N.Y.-based IBM Corp. at a cost he calls 'very reasonable.'
'I'm not sure any of these things has a capacity because they're very much expandable,' Shortt contends. 'As long as we keep buying disks, we can keep expanding as much as we want to.'
Diagnostic images generated at Centra Health immediately populate the short-term servers and long-term archive. After six months, they drop off the short-term servers because 80% of images that need to be retrieved are less than six months old, Shortt says.
But he likes a new feature in version 11 of Centra Health's Horizon PACS from San Francisco-based McKesson Corp. that makes it easier to pull images from the archive.
The PACS will automatically 'pre-fetch' any available archived images of a patient based on the body part being imaged. This enables immediate comparison of older images with new ones, saving a couple steps and about 25 seconds for the technician or radiologist.
A redundant, off-site data center going live in 2009 will give Centra Health a back-up 'hot site' it could quickly switch to for access to all information systems in an emergency. Replication software from McKesson will automatically populate the short-term servers and long-term archives at the redundant center.
The new center means the delivery system won't have to rely solely on backup tapes to recover data if it is lost from primary storage systems. 'If we had to use the tapes we could do it, but it would be painful,' Shortt says. That pain, coupled with the cost of tapes, is why he is leaning toward forgoing the practice of tape backup. 'Disks are pretty cheap but tape is still expensive.'
Going Remote
Wichita Clinic in Kansas in early 2009 will start offering remote physician access of radiology and other diagnostic images from their homes.
That won't affect the clinic's image storage strategy because remote access won't affect the speed at which storage systems find requested images. But transmission speeds for getting the image from storage to the physician home desktop won't be like the sub-second response times physicians are used to at the clinic. Even with cable Internet, the transmission speeds of images coming to a home computer could be frustratingly slow, says Leopold, the manager of radiology. 'Most physicians in the electronic world today are expecting things immediately.'
That means the clinic will make sure physicians who want the remote service understand they need to change their workflow patterns when working from home. A mammography file, for instance, can be 40 megabytes in size.
'We will make sure they understand they have to start to download images, go do something else, come read them, download more, go do something else, then come and read them,' Leopold says. 'We will start the process with our most patient radiologist.'
But the need for patience could be short-lived. Leopold believes it won't be too many years before 20 to 40 MB lines to homes will become common.
What to Keep?
A key question to answer when determining diagnostic imaging storage strategies is how many of the images taken have to be kept and for how long.
The answer lies in state laws, best practices and systemwide retention policies for the electronic health record, says Gene D'Amore, CIO and vice president of information services at Tampa, Fla.-based Shriners Hospitals for Children. The 22-hospital organization, for instance, is keeping all images for the life of the patient. That's going to really add up after the hospitals eventually adopt 64-slice or 256-slice CT scanners that can produce 7,000 or more images per study. 'Our direction is that we need to keep everything,' D'Amore says.
Centra Health also keeps all images generated since its PACS went live in 2003. 'We've never erased images and don't have plans to,' Shortt says. What they don't keep, however, is the raw unprocessed imaging data on the CT scanners beyond a couple of days because the processed images are available in short-term and archive storage.
Prior to implementing its PACS a decade ago, Wichita (Kan.) Clinic followed state law at the time and kept film of all radiology images on tape for a minimum of five years; 10 years minimum for mammograms.
In the digital world, the clinic is keeping all images live on spinning disks for 10 years and indefinitely on tapes.
Used for long-term archive and disaster recovery, the tapes only take four or five minutes to retrieve an old image because the searches start at the middle of the tape and go both ways until an image is found, says Leopold, the manager of radiology.
Taking the Long View
There's real clinical value in keeping images indefinitely, he notes. A woman's first mammography, for instance, provides the baseline measurement for future checks of tissue mass and other changes. And if a patient had knee replacement surgery at age 40, physicians will want access to those images to compare with changes in the knee region over the years.
In Nebraska, the legal medical record must be current for the past seven years, says Weise of Methodist Health. That means all diagnostic images have to be kept at least that long.
But the images of minors must be kept until age 21 or a certain number of years past the age of majority, according to varying state laws. And if a doctor wants to see the last relevant image of a patient even if it is 12 years old, the radiology department better have it, he notes. 'The safe approach is that you keep everything forever.'
Recent technology advances, such as remotely hosted PACS and portable imaging modalities, are making it easier for providers to afford digitized radiology or to provide it in more areas of the facility-or even in a mobile van.
The portable modalities don't present storage challenges beyond the usual practice of estimating the amount of data any new modality will generate in a year and adding that to expected storage needs, some experts say. Beware, however, that portable ultrasounds used in cardiology care can kick out 3,000 to 5,000 images a study, according to Weise.
With remote PACS, an organization obviously needs to have processes to ensure the vendor is properly monitoring and enhancing storage.
The big challenge comes from making sure-real sure-your remote PACS vendor is a viable company that will be around for a long, long time, warns Leopold of Wichita Clinic.
'In today's volatile world, who's to say that the vendor will be in business in five years?' he asks. 'And what happens to your images? Where are your images and how do you get them back?'
Remotely hosted PACS, however, are a good idea for small hospitals and physician practices to consider, says Sean Moynihan of the University of Virginia Health System. It is getting more difficult to find I.T. talent as the nation graduates fewer engineers, he notes.
But PACS delivered through the application service provider computing model won't suit facilities of any size using advanced CT scanners, Moynihan believes. 'As doctors in small hospitals want 32-bit or 64-bit scanners, the challenge for ASPs is how to send 7,000 images through a T-1 line without flooding that line for hours. There's no immediate answers except to buy more T-1 lines, and that's why ASP hasn't worked. We just don't have the bandwidth in rural areas.'
The End of Tape?
Another technological advance on the horizon may be the upgrading of how diagnostic imaging data is housed off-site for long-term storage and disaster recovery purposes.
Magnetic tape remains the mainstay for this storage, but some organizations are looking to move past tape, including the University of Virginia.
The delivery system uses Centera long-term storage systems from EMC Corp. in-house. But since 2005, any data retrieved from tape is copied, or 'back populated' to Centera. As data from a tape comes online, it is flagged to not go offline before being backed up to the Centera system.
Spinning disk storage systems like Centera use a redundant array of inexpensive disks, commonly called RAID technology. When a disk goes bad, it can be replaced and automatically repopulated. 'Disks are self-healing,' Moynihan says. 'When a disk goes bad, I get a message. But there's no way to tell if a tape is good over time.'
Now, Moynihan is planning for additional Centera systems for long-term storage 20 miles away to eventually replace more than 400 tapes. The project is at least two years away and he's planning how to budget for it.
More information online
For more information, visit the the hospital channel at healthdatamanagement.com. Also visit the hospital portal for more on hospitals' I.T. strategies.
