NPCR-internal code system identifying the four observation types that together form an MRI findings observation in NPCR Anmälan: prostate volume measured by MRI, highest PI-RADS category, extraprostatic extension likelihood, and seminal vesicle invasion likelihood.

This CodeSystem is used as the code binding for Observation.component.code in NPCRMRIFindingsObservation, enabling FHIR component slicing discrimination across the four findings collected from a single MRI examination.

Rationale: NPCR Informationsspecifikation §7 does not provide terminology bindings for MR findings (contrast with §7.2.2 Prostatavolym where SNOMED CT-SE 249606000 is specified for TRUL measurements). International terminologies such as SNOMED CT and LOINC do contain concepts for PI-RADS, EPE, and SVI, but NPCR documentation does not specify which to use. This NPCR-internal CodeSystem preserves documentation fidelity by mirroring NPCR's Variabelbeskrivning variable structure, avoiding researcher-introduced terminology choices.

Thesis Discussion note: Component slicing in FHIR requires a discriminating code value for each component; unlike the main Observation.code (which can be left unbound as resource identification falls back to meta.profile), component.code cannot be left empty because the FHIR validator needs it to distinguish slices. This pragmatic requirement necessitates a code value even when NPCR documentation provides none—a tradeoff between documentation fidelity and FHIR structural constraints.