Every emergency department tracks door to doctor, door to CT and length of stay. Very few track the time between a clinician needing a patient's prior imaging and actually seeing it. That interval is rarely measured, rarely owned, and often longer than the scan itself.

The 58.5 minute problem

There is no universal benchmark for prior imaging retrieval in the ED, because the answer depends on where the prior lives. A study in the local PACS may be minutes away. A study at an outside facility may never arrive at all.

The most relevant published evidence comes from a 2017 JAMIA study of ED use of health information exchange. On average, 58.5 minutes passed between a clinician requesting outside information and actually getting access to it. That study measured outside clinical information broadly. Imaging is usually the hardest part to get, because the DICOM study has to be delivered to a viewer the clinician can use, which is harder than displaying a text report.

What an hour is worth

The same JAMIA study measured what happened when access got faster. For every one hour cut from request to access time:

• ED length of stay was 52.9 minutes shorter
• The probability of a CT fell by 2.5 percentage points
• The probability of an MRI fell by 1.6 percentage points
• The probability of radiography fell by 2.4 percentage points
• The probability of admission fell by 2.4 percentage points
• Mean charges were $1,187 lower per visit

These are associations. Faster information access may coincide with other operational strengths. Even so, the size and consistency of the effects make a strong case: how long it takes to get outside data is a throughput and utilization metric that belongs on the ED dashboard. The University of Michigan's summary of the research makes the same point about emergency care.

Consider the clock the ED already runs. A study of acute abdomen patients in AJR found a median of 1.55 hours from CT request to scan start and 0.87 hours from scan completion to first report. CT intervals accounted for 29% of total ED length of stay. An hour spent searching for priors comes on top of an imaging pathway that already makes up close to a third of the visit.

Reports arrive. Images often don't.

Exchange programs often count a success when the outside report shows up. For imaging leaders, that is half the job.

A study of radiologist and ED provider perceptions of outside image sharing captured the gap. Radiologists said outside imaging was "almost never available at time of interpretation." ED clinicians called the process of pulling outside records through multiple portals long, cumbersome and time consuming. In the workflow studied, outside reports could be retrieved electronically. The actual images could be viewed only when the patient physically brought a CD or flash drive to be imported into PACS.

A report tells the clinician a prior CT exists. The radiologist needs the images. The value of comparison studies to interpretation is documented in the literature going back decades, from reading the previous report to comparing new radiographs with prior exams.

Timing beats arrival

A prior only changes care if it arrives before the ordering decision. A prior CT that shows up after the repeat CT has been ordered technically arrived during the encounter, but it did nothing to prevent the duplicate scan, the radiation dose, or the scanner time it used.

The evidence on repeat imaging supports this. A Radiology study of ED transfer patients found that importing outside images into the local PACS was associated with lower rates of later imaging. Research in Medical Care on HIE use in emergency departments found HIE use associated with less redundant imaging. A JAMIA analysis of patient crossover across an HIE identified potentially avoidable repeat CT when patients moved between organizations.

Manual, request based retrieval fails on exactly this point. Requests are made on demand, which means after a clinician has already formed a question. By then, the decision is often made.

Where automation changes the math

Medicom's clinical automation is built to remove the request step entirely:

• Retrieval starts on its own. Registration, orders or transfer acceptance trigger a prior search, so no one has to ask. Relevant priors are identified and retrieved before the clinician opens the chart.
• Images come with the reports. Outside DICOM studies are delivered into the local PACS or enterprise viewer, where they can be compared, instead of stopping at a PDF or a portal link.
• One network, any vendor. Medicom Connect provides a single exchange across outside facilities no matter which PACS or EHR they run, which replaces logging in portal by portal.
• Fewer discs. With patient access tools, patients and outside providers can share imaging electronically, so fewer CDs need to be burned, carried and imported. More on that in Death to the Disc.
• Built into the workflow. The Medicom platform puts outside imaging where clinicians already work, including within EHR workflows.

The downstream upside

Faster priors pay off well beyond the ED:

• Fewer duplicate scans: HIE use and outside image import are both associated with less repeat imaging (Radiology, Medical Care). That means less avoidable radiation exposure and more scanner capacity for patients who need a new study.
• Lower repeat imaging costs: Research on HIE use and repeat imaging costs ties exchange to savings, in line with the $1,187 lower mean charges in the JAMIA study.
• Throughput: shorter ED stays ease the crowding and boarding that ACEP links to patient harm, a finding supported by a recent systematic review of boarding and safety.
• Fewer admissions: faster outside access was associated with a 2.4 point drop in admission probability. Clinicians who can see a stable prior finding have more confidence in a discharge decision.
• Better reads: comparison studies at the time of interpretation give radiologists the context the literature has long shown matters.
• Transfers and consults: receiving teams can review outside images before the patient arrives, the scenario the Radiology transfer study examined.
• Staff time: less manual searching, phone calls, disc intake and import work for imaging and HIM teams.

How to measure it

To make prior imaging speed a managed metric, define it simply:

‍Prior imaging availability time = the timestamp the study becomes viewable in the clinical system minus the timestamp of ED arrival or the external request

Then track it separately for:

• Reports versus diagnostic images
• Local versus external source
• Automated retrieval versus manual request
• Median and 90th percentile, since averages hide long waits
• Whether the prior arrived before or after the repeat imaging decision

A reasonable starting point for local targets:

• Local priors viewable within 1 to 5 minutes of chart open
• External reports within 10 to 15 minutes
• External images within 15 to 30 minutes for non critical cases
• Retrieval fully automated at registration or transfer acceptance for stroke, trauma and aortic pathways

Proposed targets like these are a starting point, not a published standard. Stating them turns an invisible delay into something a team can own.

The bottom line

The published evidence points one way. Faster access to outside information is associated with shorter stays, less imaging, fewer admissions and lower costs, and prior imaging is where access is slowest. Automating retrieval so priors are ready before the ordering decision is one of the clearest levers an ED and imaging enterprise can pull.

See how Medicom automates prior retrieval for emergency workflows. Book a 30 minute workflow review.