So what the heck is a VNA?

There is no standard definition of a VNA, so various vendors have published their own. For example, according to Iron Mountain, a VNA:

• Must interface with other clinical systems and disparate PACS for the purpose of communicating imaging data, by means of DICOM
• Must interface with other clinical information systems for communication of reports, results, workflow, etc. by means of HL7
• Must have the ability to store the complete suit of DICOM SOP classes including presentation states and key image notes
• Must store all objects in a non-proprietary format such as DICOM part 102
• Must support the most inclusive DICOM query/ retrieve specification as a service provider for information stored in the archive at all information levels
• Must provide context management, i.e., the ability to manipulate DICOM tags so as to convert the DICOM implementation and demographic needs of one PACS vendor (or imaging application) to the DICOM expectations of another PACS vendor (or imaging application) with no significant impact on the customer's daily operation. Context management includes the ability to prepare a PACS  through HL7 for ingestion of images from another, disparate PACS
• Must handle ADT updates to image files stored in the archive
• Must support a wide variety of store infrastructure solutions so as to facilitate storage hardware upgrades and replacement with little impact on the clinical enterprise
• Must include a separate, independent, commercially available database product which supports SQL, as as to allow for easy integration with an IT department's everyday management operations
• Must ingest any type of electronic document through the use of an API and characterize that information with the lowest level association that can be made within the archive.

This lack of standardization means prospective purchasers must look closely at the specification of vendors' products to see which will meet their needs for vendor neutrality, interoperability and conformance to open standards.

According to Leonard, there are several reasons why VNA isn't being even more widely adopted.

"Overall, there's still a lack of understanding of what a VNA is," he says. "There's also trepidation at switching your archiving strategy. That can be a pretty big change."

Also, "Cost is often seen as a barrier -- as if a VNA is an all or nothing proposition," says Leonard. "In reality VNA can be staged over time. It doesn't have to be a forklift shift. That's becoming a common way to apply VNA."