Digital images provide a new cornerstone of the diagnostic process. Any radiology department that is unable to distribute and store these images in an efficient and effective manner will compromise patient care. Strategic planning was never a more critical activity than when image and information management systems are devised.

"Making mistakes in archiving can be fatal," says Stuart C. Gardner, president of SG&A Consulting in Arlington, Texas. "You must have an archiving strategy within your institution, in regards to procurement and deployment of a PACS."

Picture Archiving and Communications Systems (PACS) were originally designed to improve workflow management within the radiology department. As the need for long-term storage and wider distribution of these images became the norm, archiving became an enterprise-wide critical function. An archiving strategy will affect all aspects of clinical care from diagnosis and treatment to billing and administrative functions within the institution. If all systems are not coordinated and integrated, insurmountable problems may arise.

"PACS will continue to become the imaging layer of the EPR [Electronic Patient Record] with users in the enterprise having ubiquitous access to images and reports," predicts Rik Primo, director business development for clinical networking, Siemens Medical Systems, Inc. (Iselin, N.J.). "We will see the imaging department without walls with virtual presence of the radiologists, whenever and wherever needed."

When it comes to an image and information management system, flexibility is key. Some institutions provide care for more critically ill patients, some provide routine general care, some are primarily focused on orthopedics or cardiac care. The patient mix affects the type of archiving system that an institution must design.

Critical aspects of image storage
There are several aspects of electronic storage that must be considered when putting an image archiving system in place, including image retrieval times, disaster recovery capabilities, integration of image data with textual material, and selection of storage media.

"Customers want to have huge amounts of data online. They want access [to images] within seconds as opposed to minutes," says Vishal Wanchoo, vice president and general manager radiology systems, GE Medical Systems, Information Technology Division (Milwaukee, Wis.). The GEMS PathSpeed system employs a Storage Area Network with RAID (Redundant Array of Independent Disks), to provide short-term image storage.

"There have been major advances in the disk drive technology that populates these RAIDs," Wanchoo continues. "The disk drives go from 18 GB [gigabytes] to 73 GB, and by the end of the year, we're going to have 180 GB drives on the market because it is cost effective. All of a sudden, you have massive amounts of terabytes [TB] available in these storage area networks. The good news is that they are expandable and upgradeable."

Image review requires both navigational and examination techniques, according to Oran Muduroglu, CEO of Stentor Inc. (San Francisco). Using an analogy of reading the Sunday paper, he explains that a person uses navigational methods to skim headlines to determine which articles to read, and an examination mode to read further. In medical imaging terms, the radiologist can use low-resolution images to decide the precise image to view with high-resolution images used in diagnostic procedures. Their iSyntax technology was developed to provide rapid access to images.

The University of Wisconsin in Madison has a system designed with three tiers of image storage, according to Gary Wendt, M.D., M.B.A., vice chair of informatics and assistant professor of radiology. Using A.L.I. Technologies Inc. (Vancouver, Canada) UltraPACS multimodality software system, his department configured three levels of image storage.

"We have about 3.5 TB (terabytes) of online RAID without compression. We're getting a 3:1 compression ratio, so that's about 10 TB of real data," says Wendt. "That will be almost a year's worth of studies." This 462-bed academic health center performs about 300,000 radiological exams per year.

They are in the process of adding a Network Attached Storage (NAS) system because that will reduce the cost for midterm storage, yet make images readily available.

"With RAID, our hardware costs were about $60 per GB. NAS devices range from $6 to $12 per GB. We'll put in 5 to 10 TB of NAS as we need it. This allows a one to two second response time as opposed to a minute or two from our long term storage." The other benefit is that if the NAS should lose an image, the system triggers a "restore from tape" response.

Their long-term storage is maintained in two separate sites, using Scalar 1000 AIT Drive Libraries by ADIC (Advanced Digital Information Corp., Redmond, Wash.). Dual storage provides back-up for disaster recovery purposes.

"A realistic disaster, such as a fire in the server room or water damage, would most likely be local," says Wendt. "If that occurred, it would only take out a small portion of the hospital, and the rest would still be functional, so we would need to get imaging back online quickly." Their second long-term storage is physically located in another building.

A.L.I. Technologies Senior Vice President of Engineering and Chief Technology Officer Len Grenier explains that as a strictly PACS company their software architecture permits the use of any storage media currently available. They have built an archive adaptor that looks identical to everything upstream, so they can send images to different storage modalities.

In describing the benefits of three-tier capabilities, Grenier explains that the storage system can be configured so that there is a larger amount of online storage as opposed to having the majority of images stored on tape or an optical disk system, a scenario that necessitates pre-fetch activities. This is particularly important in non-scheduled examinations, such as a walk-in patient.

"In [Wendt's] scenario, they have some amount of high-speed RAID for initial transactions. After awhile, before falling off to just tape, it would roll over to a slightly slower, but less expensive, RAID mechanism," says Grenier. "In my view, you should never have to go to your tape copy unless you have a major disaster." The final tier, long-term storage, is accomplished using less expensive AIT (Advanced Intelligence Tape) technology.

A system such as this requires a level of sophistication to facilitate image and information retrieval and distribution. When different systems are integrated, data management challenges arise. Using a PC analogy, files are organized on a hard drive using some type of directory. With a terabyte of storage across several devices, there is no way to develop a single directory.

"You need a hierarchical structure with agents that look for data intelligently on multiple archives in a cascading way," explains George Kovacs, director of marketing strategy and development, Cedara Software Corp. (Toronto, Canada).

"Archiving must live up to real-time expectations in an intelligent way," says Kovacs. "You must assemble relevant parts of patient information using the HIS [hospital information system], RIS [radiology information system] and PACS."

An emerging trend in image management involves integration of image data with other information from across the healthcare institution, and distribution of the combined files throughout the enterprise to all clinical settings. The first step requires integration of images and textual information from a radiology perspective.

IDX Systems Corp. (Burlington, Vt.) and Stentor have formed an alliance to develop an integrated fleet of products for managing images and information across the enterprise, according to both Oran Muduroglu and IDX's Debra D. Stenner, vice president business planning and product development. IDX has 20 years of experience in image management and radiology workflow, while Stentor has focused attentions on information management with the patent-pending iSyntax technology which matches the delivery of image data to the speed of human perception.

"The first phase is radiology, but there will be other phases," says Stenner. "We are both bringing our respective core competencies to deliver one fully integrated system." The combination of iVault (a perpetual on-line medical imaging data storage model) and iSyntax from Stentor with Imaging Suite from IDX serves this purpose.

The selection of storage media is an important decision point when planning the archiving system.

"Typically, the IT department has a large vote in the strategy to employ for archiving." explains Tony Fillicelli, worldwide marketing communications manager for image and information systems, Eastman Kodak Co., Health Imaging Division (Fremont, Calif.). "Depending on their budget and mission, we could offer anything from a digital linear tape (DLT) jukebox to RAID-only storage."

Tracy Brown, clinical informatics analyst at Memorial Medical Center in Springfield, Ill., uses the Kodak Archive Manager to store to 9840 tape.

"We usually write to tape within a couple of days," says Brown. This provides redundant images for their RAID copy.

"The media that stores the data is evolving quickly," says Cedara's Kovacs. "DVD [digital versatile disc] archives are now well proliferated. AIT archives and other tape solutions continue to be used. There are some that promote the benefit of RAID." Each institution must decide which storage solution meets their needs best.

"In our experience, there is no one best media for all customers," says Mark L. Schwartz, president and CEO, IMCO Technologies (Pewaukee, Wis.) "Each has their own advantages and disadvantages. One may be faster, but more expensive. Some are re-writeable, some permanent."

In making these decisions, a department must consider the importance of data retrieval times, budgetary constraints, and level of permanence they require. Unfortunately, given the rapid advances in media development, there is a high degree of obsolescence built into whatever decision an institution makes.

Cardiology creates different data storage issues
In general, hospitals perform more radiology exams than cardiology studies. However, the cardiology department may generate the same amount of data because they perform so many motion-based studies, which create huge image files according to Matt Aitkenhead, technical sales manager HeartLab Inc. (Westerly, R.I.). In 1997, HeartLab introduced an image management system called DICOMView to support the needs of the cardiac catheterization laboratory.

"We wrote our own image archival software that records the information for a long period of time in a non-proprietary, completely standard format: DICOM-CD, which provides many benefits," says Aitkenhead. "The archival system is one and the same as the database of our Encompass system." When a clinician views a study on the workstation it is transparent as to when that study was completed. "The only difference is that the physician immediately sees the image that was done today, and the image from the DVD archive takes 20 seconds to call up."

David O. Williams, M.D., professor of medicine at Brown University School of Medicine and director of cardiac catheterization laboratory and interventional cardiology at Rhode Island Hospital (Providence) has found using the HeartLab system to provide benefits to their clinical practice.

"The images are stored in the same way they're acquired, so you retrieve the same quality," says Williams. "These images are very important in managing patients and making decisions. To have them available, and to have them of this quality has enormous utility."

Another advantage of the HeartLab system is how easily staff learned to use it.

"When we implemented this system, we didn't have to do a lot of re-training because it's very intuitive," says Williams. "We were able to have this system online within a day or so, and have everyone up to speed quickly. It is not complicated, and it focuses on what you have to do."

ASPs are all the buzz
When the discussion involves image management, the issue of ASPs inevitably arises.

"In the truest sense, an ASP [application service provider] is an offsite service managed over a WAN [wide area network] where information technology assets are taken off the premises," explains Milton Silva-Craig, chief operating officer Emageon Inc. (Birmingham, Ala.). "Your data is managed from a centralized location."

Using a different approach from the traditional ASP model, Emageon provides a turnkey implementation of PACS from image acquisition, modality testing, workstation deployment and training with a managed use contract. All equipment is maintained onsite.

designing an image archiving system

1. Why do we want an archiving system? What are our current problems? Losing films? Are we out of physical storage space? Do we need to lower costs? 2. What are our procedure volumes, and how are images produced: how many are conventional film based, how many are digital? 3. How are our data center operations being handled today? Is our Information Technology department involved with a hospital information system (HIS), a clinical information system (CIS), a radiology information system (RIS) and are those activities integrated? How many environments are we backing up? 4. How many individual platforms are we currently supporting? How many FTEs do we have to support those? Is it possible to consolidate platforms to reduce the overall number? 5. How will our personnel needs change if we deploy a new archiving system? What training requirements will we need to maintain for that personnel? 6. Do we have a plan for maintaining long-term storage of images for 20 years or more, given the changes that will inevitably occur in technology? How can we reduce possibilities for obsolescence?

"We're a service provider, but the data and assets remain within the walls of your institution," says Silva-Craig. This approach enables clinicians to use other equipment of their choice.

Paul Dandrow, vice president business development of InSiteOne Inc. of Wallingford, Conn., describes their approach.

"We have two types of clients: those who already have PACS who turn to us as a replacement archive or to expand because they're running out of space and those who need everything," says Dandrow. This company provides RAID servers that hold six months to a year of storage onsite for rapid access. Then permanent copies of all data are kept in one of two centralized data centers, one in Connecticut and on in Arizona.

"One unique feature is that from a financial model, there are no up-front capital expenditures," explains Dandrow. "We spread out the payment per study over the life of the contract." In other ASP models, the charges are paid at the beginning of typically a five-year contract period. "Our pricing is set by volume, and by whether or not you want Web access." Prices range from $2 to $7 or $8 per study.

GE offers a short-term online storage via a Storage Area Network for rapid access to images, and nearline storage that provides images within less than 10 minutes, and then long-term deep storage offsite at a data center in Chicago.

One of the possible pitfalls to long-term storage is that of obsolescence. Given the rapid development of technology, disk drives, storage media, and various system components run the risk of becoming obsolete.

"With long-term storage, you need to be able to store data for five years, and in the case of pediatric cases, for a longer period of time," explains GEMS' Wanchoo. "With our centralized storage system, we design into it the capability to migrate data effectively from media to media. For example, if we see that certain media is going to become obsolete, we'll have migration happening in the background, so that we're not left with data we cannot support. If you have storage from enough hospitals, it becomes more cost-effective because it's an economy of scale." The general idea is that offsite storage holds data the institution will hardly ever need to access, but it provides secure back-up when necessary.

Imphact Inc. (Nashville, Tenn.) provides a combined, bundled turnkey service offering that includes image archiving and information management.

"Our model is an ASP delivery model," says Imphact President and CEO Jon Lehman. "We are the primary archive, and we provide all of the servers and services out of that central utility. People on the clinical floor can go through our Web server product, RadWeb, and look at images that way. We can significantly reduce the capital they need to invest. We give the customer the option of purchasing equipment they need, or we can bundle all of that into a per procedure fee." Another benefit to this type of service is that they can make sure all image storage functions are HIPAA compliant in regards to patient confidentiality and disaster recovery systems.

Integrated systems across the enterprise
While integration of RIS and PACS is a worthy endeavor, the development of systems that consolidate all clinical data remains the ultimate goal. Most of the major vendors are developing systems that will enable image archiving functions to integrate seamlessly with information created by other departments within the enterprise, including the clinical laboratory systems, pharmacy, and administrative data systems. Given the importance of combining all relevant patient data for disease management, this goal assumes noble proportions.

There are many benefits to the electronic management of image data. The reduction in the loss of films and improved efficiency for clinicians are two of the primary advantages.

Exciting advances in technology hold promise for the future.

"Faster and affordable broadband telecommunications will provide healthcare workers with a persistent connection to IT applications, and change again the way healthcare is delivered," predicts Siemens' Primo.