Images Not Showing Up in PACS? A DICOM Send Troubleshooting Guide for Imaging Teams

Short answer: When images don’t arrive in PACS, work from the network up. First confirm the modality can reach the PACS (ping, then a DICOM C-ECHO). If the echo fails, check the IP address, port and AE titles on both sides, and any firewall in between. If the echo works but images still don’t arrive, look at the send queue and logs on the modality and PACS for rejected associations or C-STORE errors, and check whether the study landed in a quarantine or exception queue because of a patient or order mismatch.

“The tech says it sent, but the radiologist can’t see it” is one of the most common, and most urgent, calls in imaging IT. A missing study can delay a read, a diagnosis or a surgery. Here’s a practical, step-by-step way to find out where the images stopped.

How a DICOM send works (in one minute)

When a modality (CT, MR, ultrasound, X-ray) sends images, it opens a DICOM association with the destination. During that handshake, the two systems confirm each other’s Application Entity (AE) titles and agree on what they’ll exchange: the type of object (the SOP class) and the encoding (the transfer syntax). Then the modality sends each image with a C-STORE request, and the destination replies with a status. If any part of that chain breaks, images stay behind.

Step 1: Narrow down the scope

Before touching settings, ask:

One modality or all of them? One points to that device or its configuration. All of them points to PACS, the network or a router/gateway.
One study or every study? One study often means a data problem. Everything means a connection problem.
When did it start? Recent changes like a new IP address, firewall rule, PACS upgrade, modality service visit or certificate change are prime suspects.
Is it missing or just slow? Some studies arrive late because of a backed-up queue, not a failure.

Step 2: Test basic network connectivity

From the modality (or a workstation on the same network), confirm the PACS server is reachable. A ping that fails, or a modality that recently switched to a new IP through DHCP, explains a lot. Also confirm the DICOM port is open. Firewalls, VLAN changes and VPN tunnels to remote sites frequently block DICOM traffic while everything else still works.

Step 3: Run a DICOM C-ECHO

A C-ECHO (often called a “DICOM ping” or “verify”) tests the DICOM connection itself, including AE titles and port. Most modalities have a “Verify” or “Test” button on their network configuration screen. Admins can also use tools like DCMTK’s echoscu.

Echo succeeds: the connection is fine. Skip to Step 5.
Echo fails: go to Step 4.

Step 4: Check AE titles, IP and port on both sides

DICOM configuration has to match on both ends:

The modality must have the PACS’s called AE title, IP address and port exactly right.
The PACS must have the modality configured as a known device, with its calling AE title and IP, if it restricts which devices can send.
AE titles are limited to 16 characters. Watch for typos, extra spaces and upper/lowercase differences.
Common DICOM ports include 104 and 11112, but your PACS may use another. If you use DICOM over TLS, certificates must be valid and trusted on both sides.

An association that’s rejected with “called AE title not recognized” or “calling AE title not recognized” almost always comes down to this step.

Step 5: Echo works, but images don’t arrive

Now look at the send queue on the modality and the receive logs on PACS. Common causes:

Rejected presentation context: the PACS doesn’t accept that object type (for example, a newer enhanced object, structured report or vendor-specific object) or that transfer syntax (such as a particular compression). The fix is usually a configuration change on PACS or changing the modality’s send settings.
C-STORE error statuses: a status of 0000 means success. Statuses starting with A7 mean the receiver is out of resources, A9 means the data doesn’t match the object type, and statuses starting with C mean the receiver can’t understand the data. B statuses are warnings, often meaning the receiver modified some values.
Storage full or a service down on the PACS or archive side.
Timeouts on large studies (big CT or tomosynthesis series), especially over slow WAN or VPN links.
A stuck queue: one bad image blocks everything behind it until it’s cleared or retried.

Step 6: Check quarantine and exception queues

Many PACS accept images but hold them if the data doesn’t match what’s expected. The study is “there,” but no one can see it on the worklist. Look for:

Patient ID or accession number mismatches with the order from the RIS or EHR
Studies manually entered at the modality instead of pulled from the modality worklist
Duplicate identifiers (the same Study or SOP Instance UID already in the system)
Studies routed to the wrong site or facility in a multi-site PACS

Reconciling these usually requires matching the study to the correct order, which is part of the PACS administrator’s daily workflow.

Step 7: Fix the root cause, not just the study

Once the study is recovered, prevent the next one:

Give modalities static IPs or DHCP reservations.
Document AE titles, IPs and ports for every device in one place.
Monitor queues and exception lists daily, with alerts when sends fail.
Coordinate change control between IT, PACS admins and modality vendors so firewall or network changes don’t surprise the imaging team.

What our clients say

“While assisting Dr. Chan, SHIS pinpointed a DNS issue causing delays, and Cesar quickly identified the root cause. He went above and beyond by developing a custom Python application to perform network and security checks. Cesar’s dedication and skill significantly improved our workflow efficiency.” — Dr Chan, Radiologist

Source: client testimonial as shown on sacredheartimagingsolutions.com.

Frequently asked questions

What does a DICOM C-ECHO test? It confirms that two DICOM devices can open an association using the configured AE titles, IP and port. It doesn’t send images, so a successful echo doesn’t guarantee a send will succeed.

Why does the modality say “sent” when PACS doesn’t show the study? The images may have been received but placed in a quarantine or exception queue because of a patient or order mismatch, or they may still be waiting in a queue.

Are DICOM AE titles case-sensitive? Treat them as if they are. Many systems match AE titles exactly, so use the same spelling and capitalization everywhere.

Who should fix DICOM send problems? Usually a mix of the PACS administrator, network/IT team and modality vendor. A PACS consultant can coordinate all three and trace the problem end to end.

Get help with missing studies and DICOM connectivity

Sacred Heart Imaging Solutions is led by Cesar Ramirez, who brings 20+ years of healthcare IT experience across PACS, DICOM, HL7, Sectra, Visage, Epic and PowerScribe, plus a B.S. in Computer Engineering from Cal Poly San Luis Obispo. We help with PACS installation and configuration, troubleshooting, integration with EHR and RIS systems, data migration and vendor coordination. For network and IT support for medical practices, we partner with A. Computer Doctor.