6.3 HIS/RIS/EMR, PACS, and CAD
Key Takeaways
- HIS, RIS, and EMR hold orders, scheduling, and the clinical chart; PACS stores and retrieves the mammography images.
- PACS duties on the September 1, 2025 outline include storage and retrieval, backup and archive, and troubleshooting.
- Primary mammography interpretation should use original or lossless-quality data; lossy copies are not for the official read.
- CAD is a secondary reader that places marks; it does not diagnose and does not replace the interpreting physician.
- First PACS troubleshooting steps are identifier checks, send-queue review, series completeness, hanging-protocol laterality, and using a mammography-capable workstation.
6.3 HIS/RIS/EMR, PACS, and CAD
Once the detector has an image, the mammographer's job is to get the right study, at the right quality, onto the right worklist. The September 1, 2025 ARRT outline groups that work under digital image display and informatics: the medical record (HIS/RIS, EMR), PACS (storage and retrieval, backup and archive, troubleshooting), and computer-aided detection (CAD). Troubleshooting PACS is a 2025 addition. Expect items that start from a broken workflow, not from a vocabulary list.
The medical record: HIS, RIS, and EMR
These systems overlap in conversation, but they are not the same database.
| System | Spelled out | What it owns in breast imaging |
|---|---|---|
| HIS | Hospital Information System | Enterprise registration, orders, billing, admit/discharge/transfer |
| RIS | Radiology Information System | Scheduling, accession numbers, modality worklist, exam status, radiology reports |
| EMR (or EHR) | Electronic medical record | The longitudinal chart: history, problems, notes, and results the referring clinician reads |
A DICOM modality worklist typically flows from the RIS (fed by HIS/EMR orders) to the mammography unit so you select the patient instead of typing a name. Typed demographics are a classic wrong-patient path. If the worklist is empty, the order never reached the RIS, the wrong location filter is on, or the interface is down. Do not invent a new patient on the console without following downtime policy.
Image pixels do not live in the EMR. The EMR stores reports and links. PACS stores the images.
PACS: storage, retrieval, backup, and archive
PACS (Picture Archiving and Communication System) stores, retrieves, and distributes the mammography study. After you accept images at the AWS, a DICOM send moves them to PACS. The radiologist's interpretation workstation queries PACS—often through a dedicated mammography hanging-protocol application—to retrieve current images and priors.
Storage and retrieval must preserve the whole study: native or synthesized 2D frames, the DBT slice stack, and any CAD objects the facility uses. Incomplete retrieval is a clinical failure even if "something" arrived. A synthesized 2D without tomosynthesis planes is not a complete DBT exam. Planes without a 2D overview may break a hanging protocol that expects both.
Backup and archive protect legal records. MQSA and facility policy set how long images must remain available. Files retained for interpretation should be the original or lossless data, not a lossy snapshot. Backup is the copy that survives disk failure; archive is the long-term store (on-site, off-site, or both). You do not design the archive, but you do recognize when priors cannot be fetched and you escalate instead of assuming the patient has no history. Many systems prefetch priors when today's exam is scheduled; a prefetch miss is a retrieval problem, not proof that priors were never performed.
Lossless versus lossy
Lossless compression preserves every pixel so decompression matches the original. Lossy compression discards information to shrink files. FDA labeling for mammography review workstations states that mammographic images with lossy compression must not be reviewed for primary interpretation. Interpretation should use lossless or original-quality data. A blocky, overly smooth, or downsampled copy on a referring-physician portal is not the official mammography read. If the RWS image looks degraded but the AWS original looked sharp, suspect a lossy or incomplete transfer before you repeat a technically adequate exam.
Troubleshooting PACS (2025 addition)
Start with the first reversible check, then escalate to PACS/IT. Do not repeat a technically adequate mammogram solely because the radiologist cannot see it yet.
| Problem | First troubleshooting step |
|---|---|
| Missing priors | Confirm identifiers (name, date of birth, medical record number) match; search aliases and outside-facility priors; verify the prior study actually archived |
| Failed send from AWS | Check destination, study completeness on the worklist, and the send queue or error log; resend the complete study after the destination is confirmed |
| Hanging protocol laterality swap (right hung as left) | Stop the read; verify laterality markers and DICOM laterality against the patient; do not "mentally flip"; correct hanging or labeling per policy and notify the interpreting physician |
| Incomplete DBT slices | Compare slice count and series completeness at the AWS with PACS; resend the full tomosynthesis series rather than a single scout or synthesized frame |
| Images look blocky or too light only on one viewer | Confirm that viewer is not using a lossy or downsampled copy; open the study on a mammography-capable interpretation workstation |
| Wrong patient on the worklist | Do not send. Reconcile with RIS/EMR and follow wrong-patient policy |
A hanging protocol is the automatic arrangement of current and prior CC/MLO, left/right, 2D or synthesized 2D, and DBT stacks. When laterality is swapped, a right-breast finding can be described on the left. That is an informatics emergency, not a positioning critique. Electronic laterality in the DICOM header must match the patient and the on-image labeling required by MQSA. Correcting a hanging error is not the same as claiming the mammographer positioned the wrong breast.
CAD is a second reader mark, not a diagnosis
Computer-aided detection (CAD) places marks on calcification or mass candidates as a secondary reader. The interpreting physician completes an independent review, then considers CAD. CAD does not replace the physician, does not authorize the technologist to "clear" a screening exam at the AWS, and does not prove that a mark is cancer. False marks are common. A CAD-negative study can still be positive. Send CAD objects if that is the facility workflow; do not withhold images because CAD failed to run, and do not tell a patient that "the computer said it was fine."
CAD is also not synthesized 2D. Synthesized 2D is a reconstructed image for hanging and comparison. CAD is an overlay of computer-detected candidates. An exam item that treats them as the same product is testing whether you read the 2025 outline carefully.
HIPAA at a practical level
Protect protected health information (PHI) the way you already protect films: log off AWS and RWS, do not photograph worklists, send studies only through approved DICOM or secure sharing paths, and use the minimum necessary when calling another facility about priors. ARRT does not publish encryption-cipher or server-architecture specifications, and this exam will not require you to invent them. It will require you to know that a logged-in hanging protocol visible in a public hallway, a personal email of mammograms, or a hallway discussion that names a patient and her BI-RADS category is not acceptable.
If downtime forces paper orders, follow the facility downtime policy, reconcile the study to the correct accession when the RIS returns, and do not leave identifiable printouts on the AWS.
Image flow you should be able to draw
The detector creates the pixels. The AWS is where you accept, label, and send. PACS stores, backs up, archives, and retrieves. The RWS is where the calibrated diagnostic read happens. CAD, when used, is applied as a secondary mark on that interpreted dataset—not as a substitute for any box in the chain.
For primary mammography interpretation, the images opened at the radiologist workstation should be:
Computer-aided detection (CAD) in mammography is correctly described as:
A radiologist reports that only the synthesized 2D images arrived and the DBT stack is missing. The mammographer's first troubleshooting step is to: