Herman Oosterwijk, principal of Otech Inc., reported his observations of the recent Society of Imaging Informatics in Medicine (SIIM, formerly SCAR) conference that was held in Providence, Rhode Island. In Herman’s article, he laments that it was hard to find anything “new”. I have heard much of the same, from several colleagues that were also in attendance.

I stopped attending the SCAR meetings several years ago, believing that many of the presentations either focused on updates of old subjects, or introduced concepts that were too impractical for commercial implementation. I decided to break my personal embargo in 2006 and attended the meeting in Austin, Texas. I came away with the same feelings that Herman expressed this year: “nothing new”. To me it seems as if there is a major disconnect between the subject matter of the papers in the meeting hall and the subject matter of the vendor booths in the exhibit hall. Perhaps I’m growing jaded, but if an idea is not compelling enough to quickly make its way into a commercial offering, is it worth looking at? At the 2006 meeting, one of the presenters suggested the time was right to replace the mouse with wireless video gamer gloves, sort of creating the diagnostic play station. Well the creators of the Nintendo Wii thought that was a good idea, but…

Actually I did mine some nuggets in Austin, but they were found on the other side of the street. I spent enough time in the Exhibitor’s Hall to discover several technologies that would prove to be the next new thing; “The PACS-neutral Enterprise Archive”.

In Herman’s June 15 story, he reported on an interesting paper presented by representatives from the Mayo Clinic. I’d love to give them credit here, but the SIIM papers are not yet available on-line.

Mayo has apparently constructed a massive central image archive that uses “16 servers for image archiving and provides access to more than 100 million images for tens of thousand of users”.

According to the paper, the Mayo Clinic uses “a commercial PACS only for short-term archiving (less than 3 months)”. Herman points out that this dual-tier storage strategy underscores “how much information goes back and forth between the image manager and long-term archive”. Actually it underscores how little data is going back and forth. Sizing the short-term cache on the PACS is all about matching the age of the priors. In this case, the heaviest recall is obviously within three months.

At any rate, the interesting point made in this article is;

“The presenters commented that the lack of standardization between the PACS image manager and the image archive could definitely be improved.”

Well, good luck. There are numerous reasons why even the current PACS do not “play well” with standalone DICOM archives, and I don’t believe for a minute that those reasons are technology challenges. I don’t see the PACS vendors giving up the Archive any time soon. Proprietary data objects or use of Private Tags simply locks the archive (and the data) to the PACS.

Therefore, the more practical strategy for anyone wishing to pair a PACS from one vendor with an Enterprise Archive from another is to expect that the PACS will continue to store some key meta data objects as proprietary objects, or store them as DICOM objects in Private Tags, or use proprietary Value Representations (the text that describes the encoding of the Tag).

The only way to defeat this particular marketing strategy is to deploy an Enterprise Archive that is capable of Tag Morphing. When confronted with a PACS that does not treat all key meta data objects as DICOM objects stored in Public Tags, the vendor can simply program the Archive to extract a copy of the meta data and convert it to a DICOM object and place it in a Public Tag, before committing it to the Archive’s long-term storage solution. The Image Header now contains the original PACS meta data and a copy placed by the Archive in a Public DICOM tag. When the originating PACS requests the data back, the original meta data objects (in their original format) are still where the originating PACS expects them to be.

If a different PACS were to request this data from the Enterprise Archive, there are two possibilities. If the second PACS is capable of reading Public DICOM Tags, the vendor of the second PACS can be given the Group and Element numbers of all the Public Tags where the meta data can be found in the Archived version of the image data file. If the second PACS cannot read the Public Tags, the Enterprise Archive can Morph the Image Header once again and transfer the copy of the meta data from its Public Tag to any Public or Private Tag that is utilized by the second PACS to store this meta data.

DICOM Tag Morphing is an intriguing example of “reverse engineering”, but it is not new or a stretch of the imagination.  It has been perfected over time by those individuals and companies that have been doing the dirty work of DICOM data migrations.   The library of their morphing experience is simply being put to use in the Archiving application.  Tag Morphing in the Enterprise Archive is the only practical solution today to deal with the inconsistencies in the way meta data is treated by many of the current PACS. You cannot hold your breath waiting for the PACS vendors to truly standardize.

I’ve found only three vendors that have deployed Enterprise Archives capable of Tag Morphing: Acuo Technologies, DeJarnette Research Systems, Emageon Inc. If there are others, they haven’t made this capability apparent.

I’ve written a few other pieces on this subject that can be found on this web site.

PACS-neutral Enterprise Archive – Who will build it?
Looking for a PACS-neutral DICOM Archive?
An Enhanced DICOM Archive would be the ticket!
PACS Vendors think PACS-neutral Archive is crazy idea
SCAR ’06 Update

I was rummaging through some search returns on Google today, when I caught an article written back in October 2006 by Nadim Daher, a Medical Imaging Market Analyst for Frost & Sullivan. What caught my eye was his observation about the makeup of a PACS.

The article, well worth reading, goes on to discuss the advantages of building a single shared Enterprise Archive that is capable of managing both DICOM and non-DICOM data objects and therefore capable of being the archive for radiology, cardiology, and other medical imaging modalities.

While I’m all for looking ahead to the data repository for the EMR, forgive me if I am presently more concerned about building an Enterprise Archive that can exchange data between different PACS. The ability to dynamically translate DICOM header tags in order to accommodate dissimilarities between PACS, would eliminate the need for costly and time-consuming data migrations required every time a PACS is replaced.

There are a number of Enterprise Archives currently in the market that can share their data between different PACS, but most of these systems can only share DICOM data objects, and they assume that each of the PACS are capable of interpreting all of the essential meta data that is stored in the DICOM header. Unfortunately, too many PACS in operation today treat one or more key meta data objects associated with the study data as proprietary objects, or they store these objects in private tags. Few PACS systems can actually interpret all of the data transferred from another PACS, and no matter how DICOM-conformant the archive may be, if it simply accepts, stores, and returns whatever DICOM objects it is given, that archive can not solve the interpretation problem.

Nadim talks about “enterprise archive management middleware”, that special software that would “fill in this new-found gap in the structure of the modern-day information system”. In my view that middleware has to go beyond DICOM object management and Information Lifecycle Management strategies triggered by patient and study specific information stored in the header. What must be included in this middleware is the tag morphing software that would dynamically translate header information is such a way as to make the data created in PACS A become completely understandable to PACS B, and vice versa. Not only would this make it possible for disparate PACS to simultaneously share a common enterprise archive, it would also eliminate the need for future data migrations.

I have come to believe that what we now think of as a Picture Archiving and Communications System is going to bifurcate into two distinct subsystems, each evolving as they become more specialized. The front-end or clinical part of the PACS would focus on work list management, display functions, and clinical information distribution, becoming the Picture Communications System (PCS). In this new paradigm, the “A” or Archive in PACS is removed and upgraded to become the Enterprise Archive subsystem.

There is considerable speculation on which companies will be drawn to which path. It is perhaps easy to see the bigger established PACS vendors, especially those with modality product lines, continuing to develop the clinical subsystem. They have the army of software engineers required to implement and support the clinical applications. But which companies will be drawn to the evolving Enterprise Archive path? Open systems is rarely seen as an admirable quality to either the big PACS vendors or the big Storage Hardware vendors, and the concept of an Enterprise Archive absolutely demands an open system approach. There are a few specialized medical archive software vendors out there, and I think the time has come for them to step forward. There are early adopters ready to take the right steps towards building the PACS-neutral Enterprise Archive.

In a news piece released today on auntminnie.com, it appears that PACS vendor Carestream Health and storage vendor Hitachi Data Systems have entered into a collaborative agreement to create a clinical information archive. The collaboration will combine Carestream’s Versatile Intelligent Patient Archive (VIParchive) and the newly enhanced Hitachi Content Archive Platform into a single footprint.

This means that three of the top storage solution vendors (Hitachi, HP, and IBM) now have “partnerships” that add the all-important DICOM layer to an otherwise basic storage solution. This latest Carestream/Hitachi storage solution will enable multiple application servers (Radiology PACS, Cardiology PACS) from different vendors to share a common storage solution.

Unlike the DeJarnette/HP and Acuo Technologies/IBM combo systems, this new Carestream/Hitachi entry does not appear capable of modifying the DICOM file formats to accommodate differences between the vendor’s use of the DICOM header. In this case the archive stores exactly what it is given and returns the same. If the requesting application server does not know how to interpret the DICOM header created by another vendor’s server, too bad! Both the DeJarnette and Acuo software packages are capable of DICOM Tag Morphing, which effectively translates one vendor’s DICOM header format into the other’s.

The PACS vendor Emageon is also marketing an Enterprise Content Manager (archive) that is capable of Tag Morphing to accommodate any differences that may exist between the way two vendors store metadata in the DICOM header. A plus for the Emageon approach is the fact that their ECM software is hardware agnostic and can be hosted by a variety of platforms and is validated with a variety of storage solutions.

Is the Carestream/Hitachi agreement an indication that the storage wars are taking a new turn?