Data structures

The second OIDM layer: the objects that carry what was seen on an exam, keyed to the semantic foundation by code. The ladder runs Observation, Exam Finding List, Imaging Problem List, Imaging Persona. Start with the hierarchy.

• The data structure hierarchy - The four-level ladder from Observation to Exam Finding List to Imaging Problem List to Imaging Persona, what each level adds, how identifiers thread through it, and how far each level is built.
• Observation - The atomic unit of OIDM: one finding, seen or explicitly excluded, on one exam, with its location and attribute values, as it exists today inside an Exam Finding List and in the extraction pipeline.
• Exam Finding List - The per-exam structure that holds every finding declared present or absent on one imaging exam, its full field list on both branches, where its contents come from, and the FHIR and IHE encodings it is meant to reach.
• Imaging Problem List - The per-patient structure that reorganizes a patient’s imaging findings by finding rather than by date, its fields, its grouping key, the temporal status computed over it, and what it is meant to become in FHIR.
• Imaging Persona - The fourth level of the hierarchy, a stated goal with no artifact: the clinical context around a patient’s Imaging Problem List, and the life-cycle uses the 2026 deck gives for it.
• Anatomic location assignment rules - The precedence, laterality, bilateral, and specificity rules that decide which anatomic location is attached to a finding in an Exam Finding List, migrated from the imaging-problem-list development branch.
• Technical imaging findings - A draft catalog of modality-specific technical finding language, CT attenuation, MR signal, enhancement, ultrasound echogenicity, and nuclear medicine, with the search-term guidance for coding each, migrated from the imaging-problem-list development branch.
• FHIR mapping - Everything OIDM has documented about representing its data structures in FHIR, from the CDE-labeled Observation pattern of the lineage repositories to the current Exam Finding List and Imaging Problem List mappings, and the plain fact that no current code emits FHIR.
• IHE IDR alignment - What the IHE Imaging Diagnostic Report profile specifies for encoding findings as FHIR Observations, the deck’s claim that the Exam Finding List connects to it, and the fact that no OIDM repository mentions it.
• Sample data - The synthetic patients, exams, and findings that make up the Exam Finding List and Imaging Problem List sample data, what changes between branches, where the viewer bundles live, and how to regenerate everything.