Imaging informatics — reference
Reference · Dense lookup material — the verb tables, profile versions, HL7/FHIR bridge, and failure-mode catalogue. Teaching versions live in the lessons.
Actors (functions, not fixed wiring)
| Actor | Function |
|---|---|
| Modality | scanner producing DICOM objects |
| PACS | store, query, distribution, viewer/workstation |
| VNA | standards-based (DICOM) archive role (longer-term/cross-vendor) |
| RIS | scheduling, ordering, worklists, reporting, status |
| EHR | hospital-wide clinical record |
| AI / quant service | consumer of images, producer of derived objects |
Real deployments blur PACS/VNA, fold RIS into EHR, and place the AI service inside or outside the archive.
DIMSE verbs (classic networking)
AEs (AE Title + host/port); SCU = client, SCP = server; association negotiates Presentation Contexts (SOP Classes + Transfer Syntaxes).
| Operation | Verb | What it does |
|---|---|---|
| C-STORE | send | push an object to an SCP |
| C-FIND | query | search by keys |
| C-MOVE | retrieve (via move) | source SCP sends to a destination AE (third party) |
| C-GET | retrieve (to self) | source SCP sends back to me (often disabled) |
| Q/R | C-FIND + C-MOVE/C-GET | find-then-pull loop |
| MWL | worklist | C-FIND against the worklist |
C-MOVE is three-party: asker tells source to push to a separate destination AE. Final
status is precise (PS3.4 Table C.4-2): 0000 Success = all C-STOREs succeeded;
B000 Warning = one or more sub-operations failed; A801 Failure = Move
Destination unknown (no C-STOREs attempted); other failures include A701/A702 (out
of resources) and Cxxx (unable to process). A destination/connectivity/storage
failure is therefore never 0000 — it surfaces as B000 or a Failure code.
“Nothing arrived despite Success” = delivered to a different named destination, not
the asker (expectation mismatch, not a protocol lie).
DICOMweb (HTTP re-skin, parallel transport)
| Service | Maps to | What it does |
|---|---|---|
| QIDO-RS | C-FIND | query studies/series/instances via HTTP |
| WADO-RS | C-GET | retrieve objects/pixels/metadata via HTTP |
| STOW-RS | C-STORE | upload objects via HTTP |
| UPS-RS | workitem/workflow | REST interface to the DICOM Unified Procedure Step |
Auth (HTTP/OAuth vs DIMSE/TLS/ACL), paging, and batching differ by transport. Viewer capability problems (e.g. cannot render SEG) are transport-independent.
Structured results
- DICOM SEG — segmentation referencing source series/SOPs + geometry (Ch. 2).
- DICOM SR — tree of coded findings/measurements referencing source images.
- Measurements / provenance — SR can encode measurements with source refs; capture provenance (model/version/inputs/time) or the result is unauditable.
- Screenshots/PDFs are display artefacts: not queryable/computable/linkable.
IHE profiles (recipes; all Trial Implementation; verified profiles.ihe.net)
| Profile | Full name | Addresses |
|---|---|---|
| AIW-I | AI Workflow for Imaging (Rev 1.1, TI 2020) | inference workflow on UPS-RS — dispatch/track tasks |
| AIR | AI Results (Rev 1.3, TI 2025) | storage/retrieval/display of structured AI results |
| AIRA | AI Result Assessment for Imaging (PC→TI 2025) | assessment/feedback/monitoring/drift (post-market) |
HL7 / FHIR bridge
DICOM = images/imaging objects; HL7 = orders/results/demographics. Order:
RIS→modality (MWL), RIS↔EHR (HL7). Result: reporting→RIS→EHR (HL7, increasingly
FHIR). FHIR matters because discrete measurements/AI findings need to land as
structured resources (e.g. Observation), not PDFs.
Failure-mode catalogue
Silent resampling · identity mismatch / wrong patient · lost provenance · worklist collision · AI result not retrievable · no audit trail · de-id leaks. Diagnose “deployed but ignored” via viewer capability, study linkage, timing, provenance — before blaming the model.
TRACE-CT connection
Single-machine/local today, so networking is future — but it practises informatics
discipline: the QC-bundle schema (schemas/visual-qc-bundle-v1.schema.json)
encodes provenance (SHA-256 of inputs/outputs, pipeline version, geometry entries),
aggregate_qc_reviews.py produces privacy-safe aggregate evidence, and the SEG
objects it decodes (decode_seg_file()) are exactly the structured-derived-object
handling described here. The EuSoMII AI-assisted workflow pipeline (notes §3) is the
deployment shape this chapter explains.
What to retain (chapter summary)
- Actors: modality → PACS/VNA → AI service → derived object → reporter → EHR; RIS owns order/worklist.
- DIMSE verbs (C-STORE/C-FIND/C-MOVE/C-GET, Q/R, MWL) vs DICOMweb (QIDO/WADO/STOW, UPS) — same concepts, two transports. C-MOVE is three-party.
- Structured results (SEG, SR, measurements + provenance) ≠ screenshots/PDFs.
- A large share of imaging-AI failures are identity/provenance/retrieval failures; IHE profiles (AIW-I, AIR, AIRA) are the integration recipes.
- Imaging is one subsystem in the hospital’s HL7/FHIR fabric; results must cross that bridge to affect care.