SNOMED CT is constantly evolving and improving, thanks to the efforts and engagement of our many different stakeholder communities.

In this Q&A, SNOMED International Chief Terminologist Dr. Jim Case and Senior Terminologist Maria Braithwaite discuss an initiative to improve the clinical quality and consistency of the Radiology hierarchy – why changes are being made, who among our stakeholders we are working with and how it will contribute to improved clarity and consistency in SNOMED CT – and better outcomes for patients. 

Q: What is the issue with the current hierarchy and how has that affected users? 

A: There is a long-standing inconsistency with the subtypes of 363680008|Radiographic imaging procedure (procedure)| with the Fully Specified Name (FSN) varying between: ‘Radiography of X,’, ‘X-ray of X,’, ‘Plain X-ray of X.’ There are many examples where all of these terms are applied synonymously to the same concept, which can obviously lead to confusion.

As well, the modeling for these concepts is inconsistent where the value for the method attribute does not align with the FSN, a type of description which uniquely and fully captures the meaning of the clinical idea.

As this is a highly used content area affecting a significant number of users, these naming and modeling issues have resulted in suboptimal subsumption in descendants of 363680008|Radiographic imaging procedure (procedure).  For example, 268425006|Pelvis X-ray (procedure) has the FSN 'X-ray' but is modeled with imaging action 278110001 |Radiographic imaging - action (qualifier value)|.

If 268425006|Pelvis X-ray (procedure) is remodeled to align with the FSN and the imaging action of 312254007|Plain X-ray imaging - action (qualifier value), this will result in equivalency between 268425006|Pelvis X-ray (procedure) and 713021002|Plain radiography of pelvis (procedure), which is currently a subtype.

Q: What changes are being proposed? 

A: The proposed changes to the hierarchy are not minor. We need to differentiate between a plain X-ray and imaging procedures that utilize radiographic imaging in its broadest application.

We are proposing revisions to both the descriptions and model for in-scope subtypes of 363680008|Radiographic imaging procedure (procedure)| namely, concepts with descriptions “Radiography of X,” “X-ray of X” and “Plain X-ray of X.”

Q: What is your goal?

A: SNOMED International’s goal is to improve the quality of content in this hierarchy by:

• Implementing a consistent description pattern for the FSN and preferred term;

• Implementing a consistent value for the method attribute that aligns with the concept FSN;

• Improving hierarchical subsumption; and

• Inactivating duplicate concepts.

Full details of the proposal are available in this briefing note.

Q: What is the scope of this work?

A: This work will involve reviewing the relevant inconsistent descriptions and updating them. It’s important to note that we are proposing that the bulk of content in scope for this update be remodeled without concept inactivation, avoiding a negative impact on established implementations. However, where identified, duplicate concepts will be inactivated. 

We will also review inconsistent modeling and create new templates to encourage future consistency while also removing duplication. 

By drafting new editorial guidance for the addition of future content of this type, we aim to ensure that future content editing for this area of content aligns with the agreed-upon approach and does not recreate or replicate the existing content issues.

Q: What is the timeline to complete and release this work? Where are you in the process? What are the next steps?

A: We developed a briefing note and asked our Members and our community of practice to review it and provide their input by August 3, 2023, although this period will be extended to August 17, 2023 to allow for wider community input. Following the feedback process, the changes will be addressed and promoted to the SNOMED CT International Edition release sequentially over a number of releases, starting after the review and feedback period closes. The hierarchy will be reviewed in subsections and the content will be promoted over sequential releases until the changes are complete. They will also be included in the early visibility Confluence page and in the release notes of the International Edition to align with the month in which they are published.

Q: How has SNOMED International engaged the relevant communities and what are you hearing?

A: We have shared the briefing note with the Editorial Advisory Group, the Member Forum, the Content Managers Advisory Group, our Clinical Leads and relevant standards partner DICOM.  We have also added it to the early visibility Confluence page as noted above.  

Those providing feedback so far have expressed the importance of avoiding any negative impacts to established implementations. For example, inactivation of active concepts may impact established implementations. This will be managed using historical association to an active concept.

This is just the first step, however, and we will continue to seek feedback and input from the groups and organizations most affected by these changes.

Q: How can people get involved in the process? 

A: If you are interested, we suggest you review the briefing note and provide feedback by August 17, 2023. You can also contact Maria Braithwaite at mbr@snomed.org.