CPAS System Integration & Interoperability 1 — Questions and Answers
Question 1: Which interface standard is most commonly used to communicate patient demographic and order information between a Hospital Information System (HIS) and a PACS?
- DICOM
- HL7 (Correct answer)
- IHE XDS
- FHIR R4
Correct answer: HL7
HL7 (Health Level 7) messaging is the primary standard used to exchange administrative and clinical data such as ADT, ORM, and ORU messages between HIS/RIS and PACS.
Question 2: In a PACS integration workflow, an HL7 ORM message is used to:
- Transfer DICOM images between modalities
- Send radiology orders from RIS to the modality worklist (Correct answer)
- Acknowledge receipt of a study
- Encrypt image data during transmission
Correct answer: Send radiology orders from RIS to the modality worklist
The HL7 ORM (Order Message) is sent from the RIS to populate the Modality Worklist (MWL), allowing technologists to select patient exams directly on the imaging device.
Question 3: The IHE Scheduled Workflow (SWF) integration profile defines the interaction between which of the following systems?
- PACS and teleradiology vendors only
- HIS, RIS, Modality, and PACS (Correct answer)
- PACS and EHR for image sharing
- Modality and cloud archive only
Correct answer: HIS, RIS, Modality, and PACS
IHE SWF coordinates the end-to-end radiology workflow among HIS, RIS, imaging modalities, and PACS, standardizing how orders, images, and results flow.
Question 4: A DICOM Modality Worklist (MWL) server reduces errors by:
- Automatically anonymizing patient data before archival
- Allowing technologists to retrieve pre-populated patient demographics at the scanner (Correct answer)
- Compressing images prior to transmission
- Managing PACS user authentication
Correct answer: Allowing technologists to retrieve pre-populated patient demographics at the scanner
MWL pushes scheduled exam data to modalities so technologists do not need to manually type patient information, reducing transcription errors and misidentification.
Question 5: Which IHE transaction is responsible for sending a completed study notification back to the RIS after images are stored in PACS?
- RAD-13 (Modality Images Stored) (Correct answer)
- RAD-7 (Modality Worklist Query)
- RAD-28 (Retrieve Images)
- RAD-4 (Procedure Scheduled)
Correct answer: RAD-13 (Modality Images Stored)
RAD-13 (Modality Images Stored) notifies the image manager/PACS that a modality has completed storing images, triggering downstream RIS status updates.
Question 6: When integrating PACS with an EHR using FHIR, which FHIR resource is typically used to represent a diagnostic imaging study?
- ImagingStudy (Correct answer)
- DiagnosticReport
- Observation
- Media
Correct answer: ImagingStudy
The FHIR ImagingStudy resource represents a DICOM study, including series and instance references, enabling EHR systems to link to images stored in PACS.
Question 7: A PACS administrator notices that newly registered patients in the HIS are not appearing on the RIS worklist. The MOST likely cause is:
- DICOM DIMSE services are offline
- HL7 ADT feed from HIS to RIS is broken (Correct answer)
- The PACS archive disk is full
- WADO-RS endpoint is misconfigured
Correct answer: HL7 ADT feed from HIS to RIS is broken
Patient registration data flows from HIS to RIS via HL7 ADT (Admit/Discharge/Transfer) messages; a broken ADT feed means new patients cannot be scheduled in RIS.
CPAS System Integration & Interoperability 1
Which interface standard is most commonly used to communicate patient demographic and order information between a Hospital Information System (HIS) and a PACS?