The Semantics of Procedures and Diseases in SNOMED^® CT

Summary

Objectives: SNOMED^® CT is emerging as a reference terminology for the entire health care process. It claims to be founded on logic-based modelling principles. In this article, we analyze a special encoding scheme for diseases and procedures in SNOMED^® CT, the so-called relationship groups (RGs), which had been devised to avoid ambiguities in definitions.

Methods: We reformulate SNOMED^® CT’s relationship groups in the format of description logics in order to check whether RGs serve the needs they were designed for.

Results: We show that a considerable proportion of relationship groups represent hidden mereological relations. We also report discrepancies encountered between the defined semantics of many SNOMED^® CT terms and their intuitive meaning, as well as inconsistencies detected between the definition of various complex composed terms and the definition of their top-level parents.

Conclusions: We formulate recommendations for improving SNOMED^® CT by replacing most occurrences of relation groups by formally more adequate “part-of” relations.

Keywords

SNOMED CT - knowledge representation - logic

• References

• 1 Cimino JJ. Desiderata for controlled medical vocabularies in the twenty-first century. Methods Inf Med 1998; 37 (4/5) 394-403.
• 2 Spackman KA, Campbell K, Cote RA. SNOMED RT: A reference terminology for health care. In Masys DR. editor. AMIA’97 - Proceedings of the 1997 AMIA Annual Fall Symposium Philadelphia, PA: Hanley & Belfus 1997; pp 640-4.
• 3 Smith B. Beyond concepts, or: Ontology as reality representation. In Varzi AC, Vieu L. editors FOIS 2004 - Proceedings of the 3rd International Conference on Formal Ontology in Information Systems Amsterdam: IOS Press 2004; pp 73-84.
• 4 Spackman KA, Reynoso G.. Examining SNOMED from the perspective of formal ontological principles: Some preliminary analysis and observations. In Hahn U, Schulz S, Cornet S. editors KR-MED 2004 - Proceedings of the 1st International Workshop on Formal Biomedical Knowledge Representation, Whistler, B.C., Canada, June 1, 2004. Bethesda, MD: American Medical Informatics Association (AMIA) 2004; pp 72-80. Published via http://CEUR-WS.org/Vol-102/
• 5 Baader F, Calvanese D, McGuinness D, Nardi D, Patel-Schneider P. editors The Description Logic Handbook. Theory, Implementation and Applications. Cambridge, UK: Cambridge University Press. 2003
• 6 Spackman KA, Dionne R, Mays E, Weis J.. Role grouping as an extension to the description logic of ONTYLOG, motivated by entity modeling in SNOMED. In Kohane IS. editor. AMIA 2002 - Proceedings of the Annual Symposium of the American Medical Informatics Association, Philadelphia, PA: Hanley & Belfus 2002; pp. 712-6.
• 7 Spackman KA, Campbell KE. Compositional concept representation using SNOMED: Towards further convergence of clinical terminologies. In Chute CG, editor, AMIA ’98 - Proceedings of the 1998 AMIA Annual Fall Symposium, Philadelphia, PA: Hanley & Belfus 1998; pp 740-4.
• 8 Unified Medical Language System (UMLS). Bethesda, MD: National Library of Medicine. 2006
• 9 Simons P. Parts: A Study in Ontology. Oxford: Clarendon Press 1987