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Strategic Approach to PACS Storage Expansion

If your Radiology or Cardiology PACS is at least two years old, you’re probably running out of on-line storage capacity.  A more strategic approach to expanding the PACS on-line storage capacity is to deploy a completely separate storage solution, rather than simply adding more media to the storage solution that came with the PACS.  The right standalone Storage Subsystem could be the seed that grows into a PACS-Neutral Enterprise Archive.

In the two or more years since your existing PACS was installed, advances in CT and MR imaging have produced larger and larger data sets.  The addition of Full Field Digital Mammography has also added a large volume of digital image data to the PACS.  Echo and Cath Lab runs are also growing in data volume.  It is easy to understand how the amount of on-line storage  you originally projected for the PACS can no longer meet today’s actual storage requirements.

Up until a few years ago it was a common practice to configure a Radiology or Cardiology PACS with sufficient on-line storage media to manage the most recent 18 to 24 months of study data and install a Hierarchical Storage Management system to support near-line media in a jukebox, for example a digital tape library.  The near-line library has nearly unlimited expansion capabilities if it is linked to a shelf storage repository.  While this approach creates a sense of unlimited storage capacity, the practicality of the near-line library is limited by cartridge access rates and the manual loading and unloading of the tape cartridges.  All of this activity results in delays in image access.  After a few years of experience with the work flow associated with tape management, it is clear why the better solution is the expansion of the on-line storage solution.

Even if the Radiology PACS was configured with an all-spinning storage solution, the volume of storage required two or more years later has probably been underestimated. Whether the PACS is configured with a single or multiple tier storage solution, a storage upgrade is probably inevitable.  The question is, “What is the most strategic upgrade solution?”.

Adding additional media (drives), especially of the same type to the existing storage solution may not be the best solution.  In the last two or more years, the storage media technology has changed dramatically.  If the existing storage solution is approaching five years in age, it should probably be replaced, not expanded.   A completely new storage solution based on the latest technology would represent the best value, the most capacity per dollar invested.

Of course this type of upgrade, total replacement of the existing storage solution with a current generation storage solution with three to four times the capacity for the same dollars, will require a media to media data migration.   This type of data migration is not the onerous DICOM data migration that is required when one changes PACS, and that is the point!  A simple media to media migration moves all of the study data over to a new storage solution, preserving all of the ID errors, and retaining all of the DICOM idiosyncrasies of the existing PACS.  In my opinion, this could be viewed as a wasted opportunity.

The need for a storage expansion should be viewed as an opportunity to upgrade the storage technology AND normalize the image data format.

There are numerous arguments in favor of creating a PACS-Neutral Enterprise Archive: [1] Consolidation of multiple department PACS storage requirements into a single centrally administered storage solution, [2] Elimination of the cost of future DICOM data migrations, [3] Provision of data Acquisition and Management resources for imaging departments that have no PACS resources, and [4] Creation of a consolidated data repository for the Electronic Medical Record, accessible through the Physician Portal, viewable by a UniViewer display application.  The most significant problem limiting the deployment of this Enterprise Archive is the initial expense.

The same problem limited the early development of the Radiology PACS market.  Full-featured PACS was pretty expensive back in those days.  What finally got the PACS market going, what put the market on the upswing of the technology adoption curve was the invention of baby steps in the form of Teleradiology Systems and mini-PACS, individual systems that addressed individual needs that might be upgraded expanded or assimilated in to the larger more encompassing PACS that is commonplace today.

The emerging PACS-Neutral Enterprise Archive market needs a baby step, a “starter kit”, a “mini-PACS”.   I suggest that that starter kit could be a PACS-Neutral Storage Expansion subsystem for an existing PACS.  In  my next post, I’ll attempt to describe what I mean by a Neutral Storage Expansion subsystem, and why I believe that such a system is the right strategic move for any organization facing the need to expand their image storage.

Enterprise Archive should be more than a Long-term Storage Solution

The original concept of the Enterprise Archive was to provide a centralized long-term storage solution for multiple department PACS, like Radiology, Cardiology, etc. Deploying the individual “archives” incorporated into each of the Health System’s department PACS often requires supporting multiple technologies. That and the obvious redundancy means higher cost of ownership. Several years ago, the simple solution was to deploy a single storage solution that could be shared by the various department PACS, and with a growing number of Radiology and Cardiology PACS vendors supporting open storage solutions, this simple solution was a reasonable solution.

While this solution reduced some of the redundancy, it did nothing to standardize the data. As more and more Health Systems began to realize that replacement of an old PACS with a new PACS required a migration of the data to the new PACS, it became obvious that a solution was also required to address this problem. Thus the original concept of the Enterprise Archive was modified to include a solution to the expensive and painful problem of data migration.

A storage solution alone is not equipped to handle the data migration issue. The management of Radiology and Cardiology data objects requires a feature-rich layer of DICOM services on top of the storage solution. More specifically a DICOM service is required to convert the idiosyncrasies in the DICOM format used by vendor A into the idiosyncrasies in the DICOM format used by vendor B. Simply put, the tools typically used by the data migration service organizations to migrate data from PACS A to PACS B would need to be integrated into the DICOM services package that sits on top of the storage solution. The common term for this format conversion is Tag Morphing. The integration of Tag Morphing into the DICOM layer of a storage solution would enable any PACS to forward image data to this storage solution as well as retrieve image data deposited by itself or any other PACS.

Tag Morphing eliminates the need for future data migration, and Tag Morphing enables data exchange between disparate PACS. Hence the term PACS-Neutral Archive.

The evolution from shared storage solution to PACS-Neutral Archive was a pretty nifty evolution in concept, and it was clearly the genesis of an emerging new segment of the image management market. There are at least six vendors in the United States that offer a product that meets the basic requirements of a PACS-Neutral Archive: Acuo Technologies, Agfa Healthcare, DeJarnette Research, Emageon, InSiteOne, and TeraMedica. There are already several installations of such systems in the United States, and several more in Europe.

But the Enterprise Archive needs to be more than a PACS-Neutral Archive.

Several years ago the concept of accessing image data through the Electronic Medical Record (EMR) was popularized. Then and now, the concept of an EMR is that the vast majority of physicians in a Health System would post their charts and research their patient’s study results in the EMR. Therefore it would be convenient if they could access the images associated with those results while remaining in the EMR application. To date EMR products do not include the specialized viewer software required to view Radiology, Cardiology, Ophthalmology, etc. images. Furthermore the EMR is not typically configured with the volume of digital storage required to store a copy of all of these modality images. Instead of incorporating the Image Viewer in the EMR and instead of creating yet another image data repository in the EMR, a much better solution has evolved. A URL interface links the patient study instance in the EMR to the corresponding Department PACS that provides the long-term digital archiving of the study data, as well as the viewing application for the display of the images. The EMR user clicks on a study listed in the EMR and a link takes the user directly to the PACS where the images related to that study are being archived. The viewing application is the same viewer that would otherwise be accessed if the user logged directly into the department PACS. In this case, the user has the benefit of using the department PACS without having to really leave the EMR environment.

This approach is really a major step forward in information access, but it didn’t take long to foresee two significant problems. First, enterprises with multiple department PACS would have to support separate URL links between the EMR and each of those PACS. In really large Enterprises, the number of separate PACS is a big number. Second, the physicians who choose to view images from within the EMR application have to learn how to use multiple viewers, each supported by the different PACS.

A PACS-Neutral Archive can obviously become the EMR Data Repository, as it is the single enterprise archive where all image data from all PACS is stored. But the PACS-Neutral Archive alone is not equipped to provide the EMR with a viewing application. Archives are typically not expected to support a viewing application, but that is exactly what is needed to solve this new problem. The ideal Enterprise Archive would first of all be a PACS-Neutral Archive and therefore be the EMR data repository, and secondly it must support a thin client or web-delivered image viewing application that could display any of the image objects that have been committed to the Enterprise Archive. The trick of course is being able to display different types of images (Radiology, Cardiology, Pathology, Visible Light, etc.) with the same viewing software, maybe on the same display screen and in the same working session. This would be the ultimate multi-modality medical image viewer!

The PACS-Neutral Enterprise Archive configured with a Multi-modality Viewer for the EMR would be extremely useful to even a small enterprise. But there are still more key issues that need to be resolved before one could accurately describe this new kind of Archive. What kind of data objects can it accept? How does it treat different types of data objects? Does every object have to be DICOM? What display feature set is appropriate for the EMR user? Interestingly enough, all of these issues are inter-related, and there is a significant difference of opinion on these issues among the developers of the new Enterprise Archive. In my next post, I’ll present some interesting positions on these issues and attempt to defend my own personal opinions.

Cost-effective Business Continuity Solutions – So much more than Data Back-up

Most Radiology PACS currently in use have some sort of data back-up in place. At the very least, the Directory database and the Data database are backed up daily to digital tape. In my opinion, digital tape is not reliable and the problem is you don’t know what data you have lost until you try and retrieve it. My low opinion of digital tape is supported by a number of reports from the field. I suspect the vendors that continue to insert digital tape back-up solutions in their early round quotes, do so in order to keep the price of the system down, but a much better solution is worth a few dollars more.

The “tape-less” back-up is a much better back-up solution. Instead of digital tape on a shelf or in a mechanical jukebox, a far more reliable and performance-oriented solution is to store the back-up copy of the Directory and the Data on spinning disk. Thanks to today’s pricing, a multi-processor, multi-core server coupled with a disk-based storage solution is only slightly more expensive than a digital tape library. I think the reliability is worth the additional investment.

Why stop there?

Instead of just writing a copy of the Directory on the back-up storage solution, why not install a second instance of the Directory application (Oracle, Sybase, DB2, SQL, etc.) on the back-up server? Now you have a reasonably cost-effective Disaster Recovery solution, depending on where you have physically placed that back-up system.

Why stop there?

Why not add a second instance of the PACS application to the back-up server? Now you have a reasonably cost-effective Business Continuity solution. Of course this complicates the PACS application considerably. The optimal software configuration would have the two Servers (Primary and Secondary) functioning in an “Active-Active”mode, and that would mean that the Directories are being automatically synchronized in near-real-time, and the study data is being copied from Primary to Secondary on a fairly regular basis.

Only the newest generation of PACS can support this configuration. Most of the PACS being sold today can support a “tape-less” back-up server, but they do not support a second instance of the Directory application on that back-up server. The few that do support a second Directory do not support a second instance of the PACS application. Fewer still that support a second instance of the Directory and the PACS application have the back-up system operating in a standby mode. The Back-up takes over only when the Primary is off-line for scheduled or unscheduled maintenance. While this version of back-up may not sound so bad, the fact is that the failover and eventual reconstitution processes are often manual and labor intensive.

The point in all of this is, with today’s cost of hardware it doesn’t make sense to settle for a back-up solution with questionable reliability, when a much more reliable Business Continuity solution is affordable. The problem is most PACS currently being sold are “old” generations of system architecture wrapped in pretty GUI and flashy 3D applications. While GUI and display applications are important, I believe that the system architecture that supports a solid Business Continuity solution is more important, and sooner or later those old generation PACS are going to be upgraded. You can tell a lot about the longevity of a PACS, by investigating the various back-up solutions that it can support. Why start a five year contract with an old PACS? Do you have room for a forklift in your data center?

The Problem with Proprietary Data/Object Formats – their Impact long after Data Migration

This is another take on a long-standing problem with most of today’s Radiology PACS: proprietary Data/Object Formats. It has been at least four years since Presentation States and Key Image Notes were included in the DICOM standard, yet the majority of PACS vendors continue to treat these key work products as proprietary objects. The most consistent excuse is “There are many more features on our engineering schedule considered to be more important to our users.”

I can almost believe that story, since I have found that most users are not aware of the implications of proprietary data objects. Since almost every PACS supports the creation and display of Presentation States and Key Image Notes, the fact that most PACS treat these as proprietary objects is lost on most buyers and eventual users. Provided that these objects are kept within a given PACS, there is no apparent negative to their being proprietary. The user may not experience a situation where the proprietary nature of these objects presents a problem.

The problem arises when the user of one of these proprietary PACS tries to forward study data to another Facility or Health System that is using a different PACS. Whether that other PACS is DICOM conformant or not, unless it is the same PACS, those presentation States and Key Image Notes cannot be transferred, accessed, or displayed. Physicians using the other PACS will not have the benefit of seeing exactly what the radiologist interpreting the study saw in the images or what he may have typed as a text message. The benefit of these “work products” is lost.

The problem also arises when a user of one of these proprietary PACS tries to copy study data to a CD/DVD. The proprietary work products either cannot be copied, or they cannot be accessed and displayed by another PACS. This is one of the reasons why there is so much consternation over the current CD/DVD copying solutions on the market. The vendors of these proprietary PACS typically have to place a copy of their own viewing software on these CD/DVDs, because their proprietary viewer is the only way to view their proprietary study data.

The real problem will manifest itself only after the user has decided to replace the proprietary PACS with the next PACS. Data migration services will typically migrate the study pixel data to the next PACS, but few of these services currently migrate any proprietary study-related data objects. To do so would require knowing where these objects were stored in the PACS, how to extract them and how to convert them to their DICOM counterparts. This extraction, conversion, migration is not being performed and as a result, those proprietary data objects are lost forever. The images are available for historical comparison in the next PACS, but none of the proprietary work products are available. Now imagine the implication of having to window and level all of these priors again, when they are recalled for viewing with the new images. Imagine not having the spine labels, and not having any other annotation or overlay graphics created when the prior was first interpreted. That’s working without benefit of prior information, or a possible expenditure of time redoing all that work.

A PACS should treat Presentation States, Key Image Notes, .wav files, Technologist Notes, Scanned Documents, even the Radiology Report as DICOM Objects, not only so they can be shared with other systems today, but also so they can easily be migrated and used in the next PACS. DICOM-conformance is always in the user’s best interest.

Now if a prospective buyer knew the negatives associated with proprietary data objects, would they choose a proprietary PACS anyway? Logic suggests that they should think twice. At the very least, if an organization goes ahead with the purchase of a PACS that still creates any proprietary data/object formats, that organization should negotiate a “no-cost” data migration clause in their contract that pins the cost of moving these proprietary objects to the next PACS on the vendor who has continued to choose NOT to conform to the standard.

Lack of DICOM conformance is a type of vendor lock. I believe that the PACS vendors still believe that anything that complicates moving to another vendor’s PACS may persuade the organization to stay with the incumbent. It’s time to make them pay for that strategy.

Coming Up For Air

Here it is February. Where did January go? For that matter, where did December go? My bad! I’ve been so negligent with keeping my site up to date. It’s not that I was chasing snow or anything. I’ve been very busy with a number of projects; two separate RFPs for Radiology PACS, a Project Plan for a large multi-site health system, and a PACS-neutral Archive project.

I really did want to publish a commentary or two on my RSNA ’07 observations. There certainly was plenty of inspirational Material.

  • GE finally has a decent Radiology PACS (through acquisition). Now what?
  • A number of vendors start talking about PACS-neutral archives, but you really have to look hard for the vendors, and then look even harder for anyone who can speak to the subject.
  • It’s truly amazing how few vendors consider themselves DICOM-conformant, yet they do not support DICOM Presentation States.
  • Apparently 3 MP color display panels are now the norm in Diagnostic display stations.

Let’s just say I have some new things to say about some old subjects, and a few things to say about some new subjects. Sorry for the tease, but I need a little time to collect my thoughts. Check back in a few days and you’ll find some posts on such subjects as:

  • The problem with proprietary data/object formats, their impact long after data migration
  • The beauty of media-neutral storage solutions
  • Cost-effective Business Continuity Solutions, so much more than data back-up
  • Double-check that quote configuration, because there are lots of hidden costs that sneak into the picture at contract time.

Take the Archive Out of PACS

Those of you that have been following my recent posts on the subject of PACS-Neutral Archive might find it useful to visit the HIMSS or Emageon web sites to access a webinar delivered today to an audience of 70+ members of HIMSS.

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The seminar covered the subject of Tag Morphing and explained how some very common problems faced by Health Systems today can be resolved by deploying a PACS-Neutral Archive; problems such as the sharing of a single archive among multiple dissimilar PACS, and the elimination of future data migrations. The Emageon web site offers the visitor the option of downloading a collection of white papers that describe the concept of PACS-Neutral Archive and Tag Morphing in more detail.

Check it out.

Is new Stark Exemption an Opportunity?

I came across an article in Imaging Economics titled “Surveys Show Paper Legacy Tough to Shake”

What caught my eye was the second paragraph statement “A new Stark exception allows hospitals to donate health information technology in the form of an EMR to private physicians.”

I was wondering if the definition of “EMR” could be extended to radiology web viewer? Is this possibly a mechanism for providing the necessary hardware (PC), software and connectivity services to the referring physician office to get them to stop requesting paper and film?

The article is worth reading as it explains why “more than 50% (hospitals) continue to print and distribute paper lab and imaging reports.” This does not come as a surprise to me, but it occurs to me that if so many hospitals are still printing paper radiology reports, a similarly large number must also be distributing hardcopy images.

Clearly the success of a Radiology PACS depends on turning off a large percentage of hardcopy and getting the referring physicians to access images and reports from their offices electronically. I have long argued that the cost of providing a suitable PC and basic connectivity services is more than paid for by the value of the hardcopy. Many clients were concerned about the Stark implication. Is this exception an opportunity?

The article goes on to explain that 62% of hospital executives surveyed in February said their organization had no plans to donate technology. “They’re waiting to see how the government changes the landscape. How will it affect their nonprofit standing, that kind of thing.” Once again, I think this is a shortsighted point of view. The continued printing of hardcopy films is certainly affecting their bottom line. Why not take advantage of this opportunity to legally equip their referring physicians with a much less expensive method to access images and reports?