Monday, August 29, 2016

Deconstructed PACS part 2 of 4: Implementation within the VA

This is part 2 of 4 of the Deconstructed PACS series, the full video and corresponding slides of the webcast can be viewed here

The VA Midwest Health Care Network, otherwise known as VISN 23 (Veterans Integrated Service Network) implemented a deconstructed PACS between September, 2014 and August, 2015.  Our legacy PACS hardware, originally purchased as part of a Brit Systems installation was at end of life.  The leadership team in VISN 23 made the decision to proceed with a deconstructed PACS solution to replace our traditional PACS.

VISN 23 encompasses all of Minnesota, Iowa, North Dakota, South Dakota and Nebraska and small parts of additional surrounding states.  The largest facility is Minneapolis with 130,000 studies per year.  All told, the 11 facilities register 460,000 studies per year.

Prior to making the decision to proceed with a deconstructed PACS, the VISN 23 PACS and Imaging Service lines achieved successful implementations of various PACS “sub-components”.  These consisted of Corepoint Healthcare’s HL7 integration engine, PowerScribe 360®, Laurel Bridge Compass® DICOM Router, Pacsgear PACS Connect®, TeraRecon Intuition® Advanced Visualization as well as various CD burning and importing solutions across the enterprise.  Having the experience of researching, evaluating and procuring these various components encouraged the teams to move forward with a fully deconstructed PACS.

The primary three components of the deconstructed PACS in VISN 23 are Visage Imaging as the viewing solution, Lexmark Acuo as the VNA and Medicalis as the radiologists’ worklist. Due to concerns about bandwidth across the enterprise, VISN 23 chose to install a Visage server at 8 of the 11 campuses along with an Acuo local server which Acuo labels a “temporal”.  Acuo data centers are installed at both Minneapolis and Omaha with DICOM replication between these two.  The Medicalis servers are installed in Omaha.  Also installed in Omaha are the HL7, modality worklist and PowerScribe servers for the enterprise.

Prior to deconstructing the PACS, VISN 23 made extensive use of DICOM routers to ingest studies from the modality layer.  Also a third party modality worklist solution purchased from Pacsgear was implemented well ahead of the deconstructed PACS.  This allowed the biomed teams to fully configure the modalities to interact with these two systems before during and after implementing a deconstructed PACS.  This freed up time and resources during the actual implementation of the primary three components of the deconstructed PACS.

The VISN 23 team faced several challenges during implementation. First, we discovered that new internal policies prevented installation of the Visage viewer on enterprise desktops for clinical use.  Second, since the legacy PACS hardware was at end of life, implementation was begun before the legacy studies had been migrated.  Therefore, at the first site, we initiated a “just in time” or “Ad Hoc” migration meaning priors were retrieved from legacy systems for current studies as they were performed.  However, since we had to maintain the legacy PACS for the enterprise desktop viewer, we had to be cautious to avoid overburdening the legacy PACS with prior retrievals.  We managed this, but it was a delicate balancing act that went on for nearly six months.

Another challenge VISN 23 faced (and will continue to face regardless of PACS type) is that the VA’s HIS/RIS, known as VistA, will only generate an HL7 message at the time of patient registration.  This means that, essentially, there is no pre-fetch but rather a “post-fetch” or “just-in-time fetch”.  As we worked through the issues, there were times when priors were not fully available for the radiologists.  In response to this, we had a few users who innocently fetched entire jackets on multiple patients to get priors.  This caused serious system performance issues. This was easily remedied with education.

VISN 23 teams also discovered during the process of migration and priors retrieval that there were inconsistencies in some DICOM tags on these legacy studies.  We addressed this by using the evaluative tag morphing and writing capabilities of the DICOM routers mentioned earlier.

Lastly, at the request of the radiologists, support teams went back to the study description source in VistA’s RIS and improved the efficiency of the descriptions.  For example, if a CT Chest and a CT Abdomen/Pelvis were acquired together, all of the images were usually stored under the CT Chest description.  We modified the description for these studies to read “CT (CAP) Chest”.

Successes achieved during our implementation were several. The viewer and VNA were able to achieve a very tight integration for study and patient splits, edits, merges, and so on.  We found it much easier to view images from other facilities. Clinical staff easily adapted to the Visage viewer on the enterprise desktop.  The tag morphing and writing will lead to a much cleaner database.  The server side rendering of the Visage viewer allowed near instant viewing of even volumetric CT studies using minimal bandwidth. 

In summary, our vendors worked remarkably well together. VISN 23’s experience proved that a deconstructed PACS is a feasible alternative even in a challenging security environment such as the VA.

The author, Michael Ryan played a leading role in the implementation of the deconstructed PACS in the VA Midwest Health Care Network (VISN 23).  Michael has since retired from the VA and is now providing consulting services as MCR Consulting, LLC.  You can reach Mike at MCR Consulting, LLC,