Enterprise Imaging Vendor Neutral Archive (VNA)

The use of digital imaging has substantially grown in recent decades, in traditional services, new specialties, and departments. The need to share these data among departments and caregivers necessitated central archiving systems that can communicate with various viewing applications and electronic medical records. The need to aggregate and share imaging data from various departments promoted the development of enterprise-imaging (EI) solutions that replace departmental silos of data with central healthcare databases. This promoted the development of modern vendor-neutral archive (VNA) systems.

What Is Enterprise Imaging Vendor Neutral Archive (VNA)?

A VNA consolidates all imaging data from multiple systems, departments, facilities, and vendors into a centralized access point serving as a single source of truth for patient imaging information. VNAs have the ability to store and display any file format, images, or multimedia content, DICOM or non-DICOM, as well as retrieve data in its native format. The VNA can also act as a workflow engine by creating a DICOM Modality Worklist to, route, prefetch, and send notifications. Today, VNA needs to support DICOMweb and FHIR connectivity and provide various APIs to deliver the data in and out of the VNA reliably and efficiently.

What is Vendor Neutrality?

A VNA consolidates all imaging data from multiple systems, departments, facilities, and vendors into a centralized access point serving as a single source of truth for patient imaging information. VNAs can store and display any file format, images, or multimedia content, DICOM or non-DICOM, and retrieve data in its native format. The VNA can also act as a workflow engine by creating a DICOM Modality Worklist to, route, prefetch, and send notifications. Today, VNA must support DICOMweb and FHIR connectivity and provide various APIs to deliver the data in and out of the VNA reliably and efficiently.

This standardization is the “vendor-neutral” component of the name. In enterprise imaging, VNA breaks down the common barriers of a proprietary system (single vendor) to allow enterprise document sharing. All the components of the enterprise imaging workflow should use industry standards in order to communicate properly with the VNA.

Evolution of VNAs

The need to store medical images and have them easily accessible has been most common in the radiology and nuclear medicine departments and has been implemented in the form of sub-specialty and departmental (PACS/MIMPS).

Prior to VNAs, a single vendor would provide components of the system to a department, which resulted in a lack of strict adherence to standards. These prior solutions had 5 main consequences:

  • Vendor “lock-ins” The inability to combine system components from different vendors or to switch from one vendor to another, making it difficult, for example, to replace the viewer from the vendor providing the archive solution with a viewer from another vendor or to simply migrate image data from one solution to another.
  • Data silos within each department limited information sharing between departments.
  • Separate storage was required by each department which made the sharing of data, interoperability, and centralized and consolidated storage difficult.
  • Data migration challenges. Lack of universal adherence to DICOMweb and DICOM standards by the vendors caused data migration challenges.
  • No third-party integration. APIs like DICOMweb or FHIR were not used, making any type of third-party integration difficult.
In the late 1990s, archive solutions were decoupled from viewing applications to avoid vendor lock-in. There was also a concept that future PACS/MIMPS systems would handle digital image data from multiple departments and display them wherever needed. Thus, the need for VNAs in enterprise imaging (EI) consequently emerged.

Over time, storage infrastructures have been eliminated from (PACS/MIMPS) at the hardware and file system Direct Attached Storage (DAS), Network Attached Storage (NAS), and Storage Area Network (SAN) levels, and are supplied instead by non-domain-specific computer data storage vendors.

As more medical specialties incorporated images in their practice, image storage and distribution capability extended to other departments, enterprise-wide. There was also a desire to inter-operate at a higher application level, separating departmental-specific workflows, display, and analysis solutions from image storage infrastructure, using standard protocols that are image and metadata-aware, without sacrificing display performance.
VNAs may offer both digital imaging and communications in medical (DICOM) and non-DICOM image storing, with access and viewing across a range of systems and specialties. This allows for continuous workflows to be achieved and holistic patient care to ensue.

Examples of specialty departments and file types include:

  • Cardiology: Echocardiography (echo), catheterization (cath), nuclear, and ECG ultrasounds.
  • Dental: Periapical, panoramic, and cephalometric radiographs.
  • Dermatology: Photos and dermatology reports.
  • Ear, nose, and throat: MP4, JPG, and otoscopes.
  • Endoscopy: MP4, JPG, and endoscopes.
  • Mammography: Digital mammography (FFDM), computer-aided detection (CAD), and breast tomosynthesis (3-D) mammography.
  • Oncology: Fluorodeoxyglucose (FDG)-positron emission tomography (PET), CT scans, X- rays, and treatment plans.
  • Ophthalmology: Ophthalmology laser images, voice dictations, and formatted PDF reports.
  • Orthopedics: MPR, JPG, gait studies, and range of motion videos.
  • Point-of-care ultrasound (POCUS): Audio-video interleave (AVI), jpegs (JPG), and ultrasound reports.
  • Radiology: MRIs, CT scans, X-rays, voice dictation files, and advanced visualization images.
  • Sleep lab: Polysomnograms and sleep study videos.
  • Surgery: In-department X-rays, endoscopes, arthroscopes, and surgery reports.
  • Wound care: Photographs and reports.


PACS/MIMPS is a medical imaging technology that provides economical storage and convenient access to images from multiple modalities. Medical images and reports are transmitted digitally via PACS/MIMPS. The universal format for PACS/MIMPS image storage and transfer is DICOM. Non-DICOM data, such as scanned documents, may be incorporated using formats like PDF, once encapsulated in DICOM. PACS/MIMPS systems are designed for workflow improvement functions including storage, archiving, backup, and retrieval. These are typically restricted to operating on a single-system-single-department basis, PACS/MIMPS is not ideal for interdepartmental collaboration.
Unlike a PACS/MIMPS system, a VNA allows medical images received from several devices, modalities, and locations to be viewed and stored in a collaborative manner. Images can be stored using a standard interface, enabling access via any workstation, regardless of vendor. VNAs are built for long-term data storage and archiving facilitating cross-vendor migration without risk of imaging data loss. VNA is also capable of managing imaging data from different PACS/MIMPS repositories, helping increase control over medical data. VNA allows organizations to migrate from one vendor to another without imaging data loss.

Comparison of PACS/MIMPS vs. VNA. Source: SIIM

Advantages of VNAs

VNAs are a critical component of health IT and interoperability. Images and data are received and translated into a standardized format that can then be transferred to or accessed by referring physicians, radiologists, Radiology Information System (RIS), or to any radiology workstation, regardless of its physical location.

The benefits of a vendor-neutral archive include:

  • Centralized and Consolidated Storage Architecture: an enterprise archive that manages image and object data, regardless of its originating clinical system or specialty, allowing an organization to consolidate storage (hardware and software) to reduce silos.
  • Cost Savings: VNA implementations have been shown to help reduce overall costs for storage and data management by providing a centralized location. Having fewer systems to manage, back up, upgrade, and support can also result in overall operational savings.
  • Enhanced Data Security: VNA systems can help improve resilience and security for imaging data by providing storage backups and disaster recovery, logging, and other security features.
  • Interoperability: VNAs allow for interoperability across departments and systems, making access to information seamless and efficient for providers while remaining secure and HIPAA-compliant.
  • Lifecycle Management: VNAs are designed with the future in mind. They require no data migration after initial setup and offer image lifecycle management (ILM) benefits. ILM is a necessary component of any data system, as it identifies data for purging and optimizes files to lower the storage costs associated with long-term data archiving.

What Is VNA Commonly Used For?

Centralized and Consolidated Storage Architecture: A VNA can act as a centralized point of integration within an organization and into the Healthcare Information Exchange (HIE) for enterprise analytics. Management and integration support for organizations involving multiple PACS/MIMPS systems can now be managed by a centralized integration point. This less fragmented or siloed approach can help improve overall performance.

Centralized and Consolidated Storage Architecture: A VNA can act as a centralized point of integration within an organization and into the Healthcare Information Exchange (HIE) for enterprise analytics. Management and integration support for organizations involving multiple PACS/MIMPS systems can now be managed by a centralized integration point. This less fragmented or siloed approach can help improve overall performance.

Disaster Recovery (DR) is a set of best practices designed to prevent or minimize data loss and business disruption resulting from catastrophic events— from localized power outages, equipment failures, cyberattacks, civil emergencies, criminal or military attacks, and natural disasters like hurricanes, tornados, or earthquakes, etc. VNA is essential to maintaining business continuity when such events occur. Whether on-premise or in the Cloud, a VNA safely stores files located in various facilities as well as individual data centers. VNAs also perform as backup DICOM image viewers. Additionally, a database affected by a disaster event may be rebuilt with a VNA leveraging indexed metadata via a DICOM header.

Hanging Protocols provides a unique set of viewing instructions determining the layout and display of medical images, allowing the user to view an image or study based on the modality type, number of images, and comparison images as well as other user-specified criteria. Predefined Hanging Protocols allow the viewer to immediately begin the interpretation process using optimal viewing settings for the specific image or exam type. Effective use of adequately configured hanging protocols alleviates the need to arrange and adjust images upon initial display. VNAs allow hanging protocols to function properly, increasing the efficiency and productivity of the diagnostic reader.

Image Lifecycle Management is a process of storing an organization’s medical images and data and the tools needed to migrate content from one repository to another as new modalities are deployed and older ones are decommissioned. This data retention tool is used to manage the lifespan of medical images and data. Storing data at a centralized point of integration like a VNA makes it easier to manage the data and helps reduce the effort associated with multiple storages. A VNA has the ability to apply rule sets to determine when data can be removed making it more efficient in terms of data deletion because it can be done from the centralized point of integration.

Considerations and actions when implementing Image Lifecycle Management.

Image Object Change Management ensures data integrity between systems and allows one system to communicate changes to the other ones that manage copies of the same imaging objects in their local environment. This typically includes deletions of studies and images and mergers of studies. In a VNA, an Image Object Change Management assures data integrity between systems by defining how one system can transmit local modifications to other systems that process copies of the same imaging objects in their own local systems. This usually entails study merges and deletions, and medical image expungements.

Non-DICOM Content: Non-DICOM file formats including PDF, XML, or images generated by specialized equipment and modalities. VNAs have the ability to store non-DICOM content in addition to DICOM images and data. For example, a scanned document may be stored as a PDF which is converted by the PACS/MIMPS system into a DICOM PDF object with the metadata needed for easy identification and management. A key feature driving the adoption of VNAs is the ability to manage all non-DICOM data in addition to DICOM data and images and particularly non-DICOM data.

VNA for Non-DICOM Objects: Interfaces

Enhanced Data Security: VNA systems can help improve resilience and security for imaging data by providing storage backups and disaster recovery, logging, and other security features. A VNA unifies access points and procedures, allowing for more efficient access management, and auditing.

Tag Morphing (Transformation) refers to changing the values in one or more DICOM attributes. A tag that identifies the attribute is usually in the format (XXXX,XXXX) with hexadecimal numbers.

Examples of DICOM attribute tags include:

  • Patient’s Name
  • Patient’s Age
  • Allergies
  • Smoking Status
  • Clinical Trial Subject ID
  • Body Part Examined
And dozens of other attributes related to a patient record or parameters of the imaging study.
For a VNA to function at full capacity, tag morphing is executed statically through singular mapping, or dynamically through several mappings, each customized to a specific recipient. Tag morphing allows for the metadata to be managed while processing discrepancies. Any non-DICOM data sent can be standardized for easy consumption by the recipient or destination side.

Do you need a VNA? Choosing and adopting the right VNA for your organization.

A VNA should offer features that help improve workflows, such as scalability and interoperability for storing, organizing, and viewing, any imaging data with secure access from any device.

First and foremost assess your enterprise imaging ecosystem
How many systems are there? The VNA strategy largely depends on the number and variety of data sources you are going to connect to the consolidated archive. Let’s look through five options.

  • A single-department scenario. If only one department feeds images and related data to the archive, all needs are successfully covered by a scalable cloud-based PACS/MIMPS. In this scenario, there’s no rush to acquire the VNA. Yet, you may at least consider its benefits in view of future migrations and expansion of your healthcare organization.
  • A multi-department scenario. At this level, the idea of having a centralized archive becomes more worthwhile. A VNA will break down data silos created by different PACS systems, each using its own tags for DICOM files.
  • A multi-specialty scenario. Besides various systems, this case involves ingesting non-DICOM formats (such as JPEGs, PDFs, texts, and videos) used by different medical specialties. The VNA will definitely boost diagnostic efficiency as it keeps all this information in one place and makes it available across ophthalmology, dermatology, cardiology, gastroenterology, and other departments.
  • An enterprise scenario. This case is about serving the needs of multiple sites of the same hospital chain or diagnostic imaging network. The VNA with its open architecture and consolidation capabilities can become a silver bullet for data integration, management, and exchange on an enterprise level.

VNA Vendor Selection

Experience: Select a VNA solution provider with archiving and migrating studies in a vendor-neutral format from multiple PACS vendor systems. Ask for customer references.

Cost-effectiveness: Ask about migration charges for archived studies or XDS content: When using standards for ingesting and storing data, a VNA vendor should not require a migration charge for the archived study data in its system due to a software upgrade, new platform, or change in storage media or location.

Expected IHE integration profiles: A VNA should conform to Integrated Healthcare Enterprise (IHE). To ensure IHE conformance, the VNA vendor should readily publish an IHE integration statement annually.

For more information on VNA vendor selection visit this RFI/RFP Checklist resource.

VNA Configurations

  • Hub and spoke model (multi-site) allows users local access to clinical information at remote sites and
    provides dynamic synchronization.
  • Multi-tenancy allows users to manage internal organizational data independently from metadata and storage.
  • High availability and business continuity capability within a scalable framework.

Deploying a VNA: From PACS to VNA or from VNA to PAC?

Once the acquisition of the VNA is approved, you need to choose between bottom-up and top-down approaches to its implementation.
PACS to VNA means that you will expand the capabilities of your existing PACS, gradually adding new integrations and features. Many PACS vendors simplify this task, offering VNA solutions. Verify with your system provider. This step-by-step strategy can be quite feasible even at a single-department level. It also fits multi-department and even multi-specialty scenarios in the event that “multi” amounts to “several’” rather than to “dozens of.”
VNA to PACS involves the installation of a new VNA system, connecting it to all sources of images, and massive data migration to centralized storage. This strategy is more effective to cobble together numerous PACSs and other systems of healthcare enterprises and large multi-facility hospitals.

Deploying On-Premise, Cloud, or Hybrid?

To determine the best place for your data to be housed for long-term effectiveness on-premise, in the cloud, or hybrid, assess your current workflow and understand the final application.


  • Radiologist and physician viewing workflow(s)
  • HL7 and DICOM protocols behave differently with high latency
  • Faster connections cost more but can increase data access
    • Migrating to cloud storage demands security and typically an express route or encrypted end-to-end network.
  • The workflow needs change and AI demands faster data access.
    • AI algorithms may require increased investments in more performant storage.
  • Data security is paramount.
    • Enterprise Imaging vendors leveraging S3 or equivalent can gain security with data encrypted in flight and at rest (vendor dependent).

Enterprise imaging considerations before deploying on-premise, Cloud, or hybrid.

What are the primary drivers and net benefits of moving to the cloud?

What problems are you trying to solve:

  • Addressing productivity/burnout
  • Looking to save money
  • Further understanding of pathologies, clinical conditions, triaging patients, from evaluating new angles (aggregated data sources)
  • Competitive advantage

Additional questions to ask:

  • Which cloud provider would be best for our organization?
  • What if we need to switch cloud providers?
  • Are the applications we depend on going to take advantage of the cloud?
  • How are we going to get there, what tools and resources do we require?
  • Are there newer technologies and solutions that offer the same benefits as the cloud, that might be a better fit?

VNAs and Imaging Data Storage: Hot, Warm or Cold

Medical records retention is the practice of keeping patient data on file. Proper medical records retention is advisable for successful long-term patient treatment. It is also valuable for legal and compliance issues, like medical malpractice suits, licensing board complaints, or audits. Several factors determine the number of years for which medical records and medical imaging need to be stored, and the type of storage used.

As medical imaging becomes increasingly digital, medical image archives are growing in size. VNAs require significant amounts of storage, which needs to be highly scalable, resilient and easy to backup, and compliant with healthcare industry standards. When planning storage solutions for imaging archives, imaging data can be segmented based on how often it needs to be accessed, and stored in different tiers of storage.
There are three types of storage traditionally used for medical records and data. Hot storage refers to fast, easy-to-access data storage like a local hard drive or a quick-access cloud storage provider. In contrast, cold storage is for archival data that is rarely accessed and usually stored offsite. Cold storage is generally less expensive than hot storage, but can often take much longer to access. Warm data storage sits in the middle of the two, with the data stored close enough for easy access, but with fewer financial hits than your hot storage data.
Data that is processed closest to its source will be the fastest. Data that has to travel over a few different networks and arrive on to Clinician’s screen can take longer to access. All data that you need to be able to access immediately must be placed in hot storage.

Comparison of different data storage types.


Dicom Systems Unifier VNA

Dicom Systems Unifier VNA provides relevant imaging storage and retrieval services on-premise, in the Cloud, or hybrid and has customers in hospitals, IDNs, Radiology Groups, and DOD. Unifier VNA is agnostic and can be deployed with any Cloud provider public or private.

Unifier VNA Deployment Methods:

  • On-premise
  • Hybrid
  • Cloud (Public or Private). In addition to our Cloud Partners, we are also available on AWS, Google Cloud, and Azure Marketplaces.

Find us on AWS marketplace

Find us on Google Cloud Marketplace

Find us on Azure marketplace

Dicom Systems Unifier VNA Benefits:

  • Enhanced security: Cloud-based patient data storage security is subject to continuous improvements with little or no disruption to the storage and access of files.
  • Scalability: Cloud VNA can quickly adapt to the latest needs or changes in protocols, so as the patient data increases or shrinks, cloud VNA adjusts accordingly. This means that storage and retrieval capabilities are continuously operating at peak performance.
  • Cost-Savings: Storing patient and provider data in the cloud may produce a significant reduction in the size of the IT staff without a decrease in performance.
  • Protection: Cloud VNA information is safe and secure, insulated from, for example, power outages or sabotage.
  • Access: Provides access through any computer or mobile device, anywhere there is Internet access, 24/7/365.
  • Interoperability: Addresses the unknown: Reduces the stress of upgrades by seamless integration into the current cloud operating system.
  • Enhances interoperability by providing a long-term, sustainable strategy that offers universal storage, viewing, and sharing solutions without the overhead and cumbersome qualities of an on-prem option.
  • Standard archive functionality – DICOM Support for standard archive functions is built-in: Store SCP, Query/Retrieve SCP, Storage Commitment SCP, and Verification SCP/SCU
  • 100% web-based solution
  • JPEG2000 compression and JPEG-LS compression
  • Transfer syntax handling – Configurable transfer syntax support allows databases to be converted to and stored in any specified transfer syntax
  • DICOM and HL7 pre/post-filtering, morphing, and routing – Powerful rule-based DICOM tag morphing and routing.
  • Virtual Archive Data storages capability gives you a flexible, low-cost alternative
  • Self-recoverable database architecture with DICOM engine for image archiving and management
  • SNMPv3 management module with more statistics and monitoring
  • Easy HIPAA-compliant logging and monitoring of all DICOM transactions in a user-friendly format
Learn more about our VNA projects:
Cancer Center Deploys Dicom Systems Unifier Vendor Neutral Archive (VNA) on Google Cloud Case Study

Dicom Systems Awarded DoD Dental Records Archiving Contract

Want to learn more about VNA with the Dicom Systems Unifier platform? Meet with one of our enterprise imaging workflow experts.