By Don K. Dennison

A lot has been written about the merits of using a vendor neutral archive to provide a shared, consolidated medical imaging record repository that spans multiple facilities and clinical domains.

In today’s consolidated enterprise, having a solution to provide a high-quality, longitudinal patient imaging record to any authorized user or system is a keystone of an effective imaging strategy.



However, regardless of how well a VNA may be working, if it has many different or underperforming PACS connected to it, the cost savings and business objectives may not be realized.

For some organizations, consolidating the myriad PACS at their various facilities into a shared enterprise PACS is the best solution. They see the benefits of having a single, shared radiology PACS and a shared cardiology PACS in the effort to maintain and support the systems. These shared systems allow them to more easily centralize and standardize support services and knowledge. Collaboration and communication within a system is inherently easier than across systems. And if the PACS has comprehensive security controls, organizational policies can be applied consistently.

Enterprise PACS, VNA or both?
Like many things in imaging informatics, the real world is rarely so binary. There are many reasons that a combination of these approaches is used:
• In enterprises that are geographically dispersed, a single PACS may not be able to provide the necessary performance to users across the extended network. Multiple, regional systems may be required.
• In some cases, the legal business relationship among the facilities may be more of a partnership than ownership, and some level of autonomy is desired.
• Workflow at large academic centers with subspecialty reading often differs from that at community hospitals where more general reading is done. Consolidating on a single enterprise PACS may not be accepted if the solution is not ideal for everyone involved.

If an enterprise viewer is used for non-diagnostic user access, the system or systems to which it is connected will impact the overall integration complexity and cost. It may also result in inconsistent imaging and information display performance, if the source systems vary in their responsiveness.

While it is a generalization, many PACS include imaging exam acquisition and quality control (QC) workflows optimized for their intended clinical domain — radiology or cardiology, for example. VNA often provide general capabilities that are adapted, through configuration, to the acquisition workflow within each domain. The system may also include tools to capture so-called enterprise images, such as dermatology, endoscopy, wound care and others.

Even if an organization consolidates facilities on shared enterprise PACS, a VNA may still be required for managing and exchanging imaging records outside the clinical domains of the PACS, and the facilities it serves.
What is right for your organization?

Determining the most effective imaging IT solution architecture for today and tomorrow requires an examination of your current and projected needs and workflows. The design should be based on the organization’s strategy, vision, values and policies.

If the organization is regionally focused, a single PACS (per clinical domain) may yield significant benefits among the users and cost savings. As patient referral patterns tend to be localized to a region, a single PACS can reliably provide a common diagnostic image repository.

When selecting an enterprise PACS, several capabilities are commonly required, including the ability to manage multiple patient identities (including an MPI value), multiple procedure sets, organization-specific QC workflows, different pre-fetching rules and others.

Depending on the image archive capabilities of the radiology PACS, it may be capable of acting as the long-term archive for cardiology exam data and even enterprise images. Capabilities to integrate with enterprise viewer, image sharing and health information exchange applications should also be evaluated.

When an organization is large and distributed over several regions, sharing an image repository, such as a VNA, can provide a common view of all of a patient’s imaging records. Each connected PACS may serve multiple facilities within a region. In this case, the merits of an enterprise PACS are experienced among the facilities within a region where a patient commonly seeks services, and the benefits of the VNA are realized when patient record access needs to span regions.

Careful attention should be paid to how a PACS interoperates with a VNA that is acting as the long-term image archive, as this can vary and any gaps may prevent information access, cost reduction and performance objectives from being met.

An effective enterprise viewer solution can significantly reduce the number of users who access the PACS, so it is an important part of a comprehensive medical imaging strategy.

About the author: Don K. Dennison has spent more than 15 years working in the medical imaging informatics industry. He serves as a consultant specializing in imaging informatics. Dennison serves on the board of directors of the Society for Imaging Informatics in Medicine (SIIM) and several committees. He also chairs some American College of Radiology (ACR) committees.