Fig. 1

- Projection of image finding terms to feature concepts in SNOMED CT “is-a” hierarchy. Part of the “is-a” hierarchical relationships is illustrated with three examples demonstrating the rules to determine the semantic distances. Four image finding terms: “cirrhosis”, “hepatic fibrosis”, “splenomegaly” and “fatty liver” are considered. The level-4 concepts are regarded as feature concepts. In this case, feature concepts: “liver finding”, “abdominal organ finding” and “fatty liver” are involved. a The term “cirrhosis” at level-7 is the descendant of “liver finding”. Their semantic distance is 3 because there are three “is-a” links between them. b The semantic distance between “hepatic fibrosis” and “liver finding” is 2. c The term “splenomegaly” is not a descendant of “liver finding” but the descendant of “abdominal organ finding”. Thus, the semantic distance between “splenomegaly” and “liver finding” is infinity and that with “abdominal organ finding” is 2. Finally, the term “fatty liver” at level 4 is also a feature concept and the semantic distance is 0