Orthanc and OHIF for Digital Pathology: What the Open-Source Stack Can and Can't Do

Orthanc stores medical images; the OHIF Viewer displays them in a browser. Neither charges software licence fees or is CE-marked as a medical device. Budget for integration, secure operation and the requirements of your intended use.

Medired builds on this stack. Here is what it does, what needs extra work and where its limits matter.

What does each component do?

Orthanc is the archive. It receives, stores and serves images using DICOM, the medical imaging standard. It is a Picture Archiving and Communication System (PACS).
OHIF is the viewer. Users open it in a web browser. It retrieves images through DICOMweb, the web interface to a DICOM archive.
Plugins and integration connect the workflow. They add features such as whole-slide support and links to your Laboratory Information Management System (LIMS). HL7/FHIR interfaces exchange clinical information through plugins and an integration layer, rather than native Orthanc functionality.

Orthanc's storage can grow from local disks to larger database and storage systems. The right configuration depends on image volume and availability requirements.

Can it handle whole-slide images?

Yes, with the right import tools and viewer configuration. Whole-slide imaging (WSI) produces very large images with several zoom levels. There are two ways to get them into the archive:

DICOM export: a compatible scanner sends DICOM slide images to Orthanc.
Conversion: supported scanner formats are converted to DICOM. Orthanc's whole-slide imaging tools include a converter.

Test your scanner's files, image quality and viewing performance before committing. DICOM support alone does not guarantee that every viewer handles every slide. Macro photos and other DICOM images, such as CT or MR, can share the archive.

What does it cost to run?

Orthanc and OHIF have no per-seat, per-study or per-scanner licence fees. You still pay for:

Infrastructure: servers, image storage and backups.
Integration: connecting scanners, macro capture and the LIMS to the correct cases.
Operation: security, updates, monitoring, recovery testing and support.

Compare the full cost over several years with a commercial platform. The lab director's guide gives indicative component budgets.

What about CE marking and primary diagnosis?

Neither Orthanc nor OHIF is CE-marked as a medical device. The OHIF FAQ explicitly states this and makes compliance the user's responsibility.

EU software classification depends on intended purpose. Storage and communication differ from functions that support diagnosis; see the European Commission's MDCG guidance.

Our focus is archiving, macro documentation, remote review and consultation. Teaching and research are other uses. Do not assume that calling a workflow a “second opinion” settles its regulatory requirements.

For primary diagnosis, your lab needs a validation plan and regulatory advice for its intended use. Lab validation should not be treated as a substitute for meeting applicable regulations. A CE-IVDR viewer is another option to evaluate with an integrator, including compatibility with the archive.

What needs to be added?

The archive and viewer do not replace your LIMS, case worklist or reporting system. Some scanner-specific analysis features also remain in the manufacturer's software.

A professional installation should include:

Encrypted connections, controlled access and audit logs.
Backups with scheduled restore tests.
Automatic case linking and checks for mismatched identifiers.
Tested updates, monitoring and storage capacity planning.
A named support contact with agreed response times.

Who is it a good fit for?

Consider it if you want an archive you control, equipment from multiple vendors and remote review without platform licence fees. If you need a single CE-IVDR platform for primary diagnosis from the outset, compare commercial options too.

How Medired operates it

We install and maintain Orthanc and OHIF, with plugins and LIMS integration. We normally operate them on your infrastructure; dedicated EU hosting is available when needed. You pay for setup, integration and ongoing operation. The engineer who designs the system supports it.