DICOM for Digital Pathology Interoperability

by Dan Hosseinzadeh, CEO, Pathcore and Co-Chair, DICOM Working Group for Pathology (WG-26)

Recently, there’s been a whirlwind of activity in the DICOM community surrounding digital pathology. Among the highlights were the DICOM Digital Pathology Connectathon events that brought vendors from all corners of the digital pathology community together for demonstrations of interoperability. DICOM’s Pathology Working Group (WG-26) has organized four DICOM Digital Pathology Connectathons during the past year.

“The DICOM Connectathons are the next best thing to have happened in Digital Pathology since FDA approval of WSI for primary diagnosis. It is encouraging to see different vendors working together to make their systems plug & play in our labs. This affirms that we are on the right path ahead for WSI”. – Liron Pantanowitz, MD, UPMC

In this blog post, we’ll review the motivation behind adopting the DICOM standard for digital pathology, introduce WG-26 and discuss the need for hosting DICOM-based pathology Connectathons (we had four since last year!). These four interoperability events, hosted by the volunteer-run WG-26, were impressive feats, and will have a lasting positive impact on our evolving field.  More on the DICOM Digital Pathology Connectathon can be found here.

Demonstrating interoperability in digital pathology using open, free and publicly available DICOM standards

What is DICOM? DICOM (Digital Imaging and Communications in Medicine) is the international standard to transmit, store, retrieve, print, process, and display medical imaging information.  DICOM makes medical imaging data interoperable by enabling integration of image acquisition devices, archive solutions and workstations across different vendors. In radiology, the DICOM standard is universally used. DICOM has been deployed in hundreds of thousands of medical imaging devices worldwide, with hundreds of billions of DICOM images archived to date[1]. The standard is administered by the DICOM Standards Committee with support from the Medical Imaging Technology Alliance (MITA) division of the National Electrical Manufacturers Association (NEMA), which holds the trademarks and copyrights, and  publishes the standard along with plans and activities at https://www.dicomstandard.org/.  A recent article from the National Academy of Medicine: Procuring Interoperability: Achieving High-Quality, Connected, and Person-Centered Care highlights the adoption of standards for true interoperability, resulting in more patient-centric and high quality care for patients.

DICOM is the universal standard for medical imaging

With pathology making the transition to a digital practice, many vendors are commercializing hardware and software solutions to support digital pathology.  For example, one vendor may create database/archival systems, another vendor may design whole slide imaging scanners, and yet another may build viewers, workstations and analysis tools. In order for these devices to communicate successfully, a common data standard must be implemented by the vendors in order to achieve true digital pathology interoperability.  Without a vendor neutral pathology imaging format, these devices are siloed in labs around the world, creating massive workflow bottlenecks.  As a result, DICOM established Working Group 26 (WG-26) to expand the DICOM standard to pathology imaging using open, free and publicly available standards.

Who is WG-26? DICOM’s Working Group 26 (WG-26) was established in 2005 to develop and extend the DICOM medical imaging standard for pathology and whole slide imaging (WSI). It is run by a group of dedicated volunteers comprised of members from industry, clinicians and academics who have common interests in advancing the field of digital pathology through interoperability and standards development.  DICOM and WG-26 are public entities; anyone can become a member and attend their meetings. WG-26 meets by teleconference and at international pathology events including Pathology Visions, United States & Canadian Academy of Pathology (USCAP) Annual Meeting, Pathology Informatics (PI) Summit, European Congress of Pathology (ECP), European Congress on Digital Pathology (ECDP), and more. You can join our mailing list here or learn more about WG-26 here.

Why organize Connectathons? In order to encourage vendors to become active participants in standards development and increase the availability of DICOM-compliant solutions in pathology, WG-26 organized several DICOM Digital Pathology Connectathon events. The Connectathons have been a blend of education and technical validation for implementers. Vendors mix solutions, experiment, and demonstrate that pathology images and data can be passed from one system to the next, thereby achieving interoperability. The Connectathons provided an opportunity for those interested in DICOM to discuss one-on-one with vendors, to see interconnected, interoperable systems working together, and to participate in panel discussions where vendors and DICOM experts discussed their vision for DICOM and answered attendeed questions.

The fourth DICOM Digital Pathology Connectathon took place during Pathology Visions 2018 in San Diego and was the largest and most successful event to date, drawing the most participants and generating impressive outcomes.  Digital pathology vendors demonstrated true interoperability through the DICOM standard, since whole slide scanners, image viewers and workflow solutions from different vendors successfully communicated data between each other and showed that the images could be used by the receiver. A total of thirteen (13) groups have participated in at least one of the four events.  You can read more about these events here.

Remember, if you are purchasing or upgrading a digital pathology system in the next two years (whether the solution is image management, slide viewing, or workflow related), consider if these investments can interoperate with other devices years down the road. If you are in the midst of adopting digital pathology, consider how DICOM affects your procurement process today and in the future. Chat with your colleagues from radiology to learn more about their experiences with DICOM.


[1] Brad Genereau. Introduction to DICOM and DICOMweb Concepts. FHIR Developer Days, 2016

Disclaimer: In seeking to foster discourse on a wide array of ideas, the Digital Pathology Association believes that it is important to share a range of prominent industry viewpoints. This article does not necessarily express the viewpoints of the DPA, however we view this as a valuable point with which to facilitate discussion.

6 comments on “DICOM for Digital Pathology Interoperability

  • Jon Aarbakke says:

    Hi Dan,
    I have a background in radiology and a half-decent grasp of DICOM from that angle. I am curious to know how much work, if any, has been done on creating metadata profiles for the “pathology” information. By that I mean not all the technical details of scanners and images, but such things as sample numbers, cassettes, staining data, macro photography, macro descriptions and so on. I have this (blurry) vision exploiting the study-series-image/object hierarchy to create a single self-contained structure where you might have a very rich representation of the case/sample/study in a single DICOM study. You could have one series containing say all images scanned from one cassette and any photos of the corresponding tissues; the next DICOM series for the next cassette, and so on. Would that be “neat”? Is it being done? You could then also chuck in the report and so on. I write from a position of near total ignorance, as I am sure I have by now revealed. Yours, Jon Aarbakke

    Reply
    • Hi Jon,

      Great question! The goal of DICOM, as you have pointed out, is to create a persistent record of an image, which by itself, contains the minimum information required for diagnostic use.
      As a result, DICOM WSI objects can encode a “ton” of information about the specimen in addition to the study, series and image information, that are required in all DICOM objects. Attributes such as optical path, magnification, scanning properties, collection method, fixation, processing, staining, and anatomical information (among other attributes) can be encoded in DICOM WSI objects. Much of this data model became part of the standard in 2008 and was introduced via Supplement 122 “Specimen Module and Revised Pathology SOP Classes” (see ftp://medical.nema.org/medical/dicom/final/sup122_ft2.pdf).

      And yes, there is a way to group related images together in a study (i.e. a series for each macro and slide created from a block or specimen). Each of these images would be a unique series pyramidal WSI objects are usually encoded as multiple instances belonging to the same series. And yes, having related images is “neat”!

      DICOM WSI is in use. Most notable is the VGR region (i.e. a network of hospitals) in Sweden, who adopted DICOM for their pathology workflow. However, the vast majority of adopters are using proprietary systems.

      Regards,
      Dan

      Reply
  • Thank you very much for this article! The Connectathons are a great way to promote the collaboration between digital pathology solution vendors and pathology community. Is there a next one planned already?

    Reply
    • Hi Aleksandra, our pleasure. There’s a Connectathon planned for the ECDP conference in April. Please also see this link for more information on upcoming and past Connetathons: pathcore.com/connectathon

      Reply

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