Why Does VNA Matter – and How Do You Identify it?


In this series of blogs we’ve been arguing that a Vendor-Neutral Archive (VNA) approach – where VNA needs to be read as describing a medical imaging system that can support the exchange of medical image content, however and wherever it has been generated – is a highly promising new way of thinking about building common NHS-wide electronic medical records, which the National Programme failed to do

We think that electronic medical records can be achieved by adding more fields to the system so that more patient data can be exchanged. You may not agree, but nonetheless, you are still going to have to engage with the VNA approach. This is because VNA in the context of your medical imaging platform – your PACS (Picture Archiving and Communications System) – is becoming more of an issue for health informatics leaders.

Why? Because as you start to step outside national NHS IT specifications, you have to start thinking about how to make your systems more interoperable. That’s because you will need to mix and match technology from multiple, non-Programme suppliers, and without being locked-in.

So what is a VNA exactly? Well, to be truly neutral, a VNA has to be able to make sure its tags – the metadata used to describe its contents – can be read by another vendor’s.

The reality is that not many VNAs meet these stipulations. That’s why you need to look for a VNA system where tagging (or any and all metadata manipulation, so also how it handles the headers or indexes digital image content) is only ever done in such a way that it can be preserved if a PACS file gets moved from one system to another.

That is to say, for maximum flexibility and reliability, a PACS VNA system has to be able to preserve the original tags and other metadata so that these can be restored at any point.  It also needs to be able to ‘normalise’ any platform-specific differences so that its repository can manage and interpret all documents in a uniform way, but still be able to access all the information it needs to.

That sounds like a stiff set of requirements. And it’s true there aren’t enough truly VNA-capable suppliers out there. This means, as the buyer, you have to get satisfactory answers to key questions like, ‘Can it handle content from a variety of PACS systems/modalities?’ Or ‘Does it work with any brand of storage system?’.

You will also want to know to what extent it supports true cross-document sharing (XDS), so that via a clinical portal any type of patient content (both DICOM and non-DICOM) can be called up, viewed and manipulated, regardless of its origination.

It would also be helpful if it can support lower-resolution versions of images, e.g. for quick browsing by a GP for example.

You need to be asking these questions of the next PACS vendor that comes through your door –  regardless of whether or not you think, as we do, a good VNA that adds in content management capability can be a very powerful tool for getting us nearer those elusive electronic medical records.