What the study actually measured
The research, published in Clinical Radiology and first covered by Radiology Business, is a retrospective cohort of 1,246 adult trauma patients admitted to an academic hospital in Johannesburg, South Africa between January and March 2022. Of that group, 729 patients — 59% — underwent CT imaging.
Instead of treating "imaging" as one block of time, the researchers broke the CT workflow into three separate intervals and tested each one against emergency department length of stay (ED-LOS): CT time (order to completed scan), preliminary report turnaround time (scan to the first readable report), and final report turnaround time (scan to the signed final). That decomposition is what makes the finding useful — it isolates which part of the imaging pipeline actually moves the outcome that matters to ED throughput.
Who gets stuck longest: CT patients vs. everyone else
Across the full cohort, average ED-LOS was 8.9 hours. But needing a CT scan at all was already a strong predictor of a longer stay:
| Group | Mean ED length of stay |
|---|---|
| Full cohort (n=1,246) | 8.9 hours |
| Patients who received a CT (n=729) | ≈11 hours |
| Patients who did not receive a CT | ≈6 hours |
Nearly a five-hour gap between the CT and non-CT groups is a large signal on its own. The more interesting question — and the one the study was really built to answer — is which part of the CT pipeline is responsible for it.
Three intervals, one independent driver
Among the patients who underwent CT, the three workflow intervals looked very different from one another:
| Interval | Median time |
|---|---|
| CT time (order → completed scan) | ≈5 hours |
| Preliminary report turnaround time | ≈2 hours |
| Final report turnaround time | >11 hours |
In an unadjusted analysis, CT time looked like it mattered — patients waited longest for the scan itself. But that's the kind of correlation that's easy to misread as causal. Once the researchers ran a secondary analysis adjusting for age, sex, shock index, Glasgow Coma Scale score, and CT time together, CT time dropped out as a significant factor. Only preliminary report turnaround time remained independently associated with ED length of stay.
The size of that effect: each additional hour of preliminary report turnaround time corresponded to more than a half-hour increase in emergency department stay. The scan itself — the part of the pipeline that capital spending and scanner throughput initiatives typically target — was not the independent lever. The time it took to get a readable report back was.
Why "report-drafting speed," not scanner throughput, is the metric
This matters because most imaging capacity conversations still default to the scanner: more slots, more machines, faster acquisition protocols. Those investments shorten CT time — the interval this study found was not the independent driver of ED-LOS once reporting speed was accounted for.
The interval that did survive adjustment — preliminary report turnaround time — sits entirely on the reading-room side of the workflow: the minutes between a completed scan landing in PACS and a radiologist (or a radiologist reviewing an AI-generated draft) producing a report a clinician can act on. That's consistent with separate research on the benchmarks side of this question: ACR guidance calls for routine CT reads to be signed within 24 hours, but actual turnaround benchmarks frequently run 36–72 hours, and a separate study found ED CT turnaround ran 34% longer without an on-site radiologist — both pointing at drafting capacity, not scanner capacity, as the bottleneck.
For EDs and the imaging-center or teleradiology partners that serve them, the practical implication is a measurement one: track the scan-to-preliminary-report interval as its own KPI, separate from door-to-scan or scanner utilization. This study suggests it's the interval most tightly tied to how long a patient occupies a bed.
What the study can't tell us
It's a single-center, retrospective analysis of trauma patients at one academic hospital in South Africa over a three-month window — not a multi-site U.S. trial, and not a study of routine (non-trauma) CT. The authors themselves note that a retrospective design can show association, not causation: it's possible that sicker or more complex patients both generate longer reports and stay longer for reasons unrelated to the report itself. But the mechanism the study isolates — that the gap between a completed scan and a usable report, not the scan, tracks with how long a patient stays — lines up with what turnaround benchmarking research shows in other settings, which is why it's a reasonable signal for imaging and ED leaders to act on rather than dismiss.
Where xAID fits
This finding describes exactly the interval AI-assisted CT reporting is built to compress: the time between a completed scan and a structured first draft. xAID's foundation-model system generates that draft immediately, an in-house radiologist reviews every preliminary before it goes out, and the report arrives ready-to-sign for the client's reading radiologist — shortening the interval this study flags as the one independently tied to how long a trauma patient occupies an ED bed, without touching scanner throughput at all.
Frequently asked questions
What did the study find about CT reporting and ED length of stay?
A retrospective study of 1,246 adult trauma patients treated at an academic hospital in Johannesburg, South Africa (January–March 2022) found that emergency department length of stay averaged 8.9 hours overall. Patients who had a CT scan stayed nearly 11 hours on average, versus about 6 hours for those who did not. After statistical adjustment, only preliminary CT report turnaround time — not the CT scan itself — remained independently associated with how long patients stayed.
Does CT scan speed (acquisition time) affect ED length of stay?
Not independently, according to this study. Median CT time (order to completed scan) was about 5 hours. But once researchers adjusted for age, sex, shock index, Glasgow Coma Scale score, and CT time together, CT time dropped out as a significant factor — only preliminary report turnaround time remained independently linked to length of stay.
How much does report turnaround time affect ED stay?
The study found that each additional hour of preliminary report turnaround time was associated with more than a half-hour increase in emergency department length of stay. Median preliminary report turnaround was about 2 hours in the cohort, while median final report turnaround ran past 11 hours.
Does this trauma-center finding apply to routine CT and other EDs?
The study is a single-center, retrospective analysis of trauma patients in South Africa, so it cannot prove causation and may not generalize directly to every ED or imaging setting — the authors note this limitation themselves. But the mechanism it isolates, that the interval between a completed scan and a readable report drives occupancy more than the scan itself, matches what turnaround-time benchmarking research shows across practice types, which is why reporting speed, not scanner throughput, is the metric worth tracking.
Source: Sherry et al., "Computed Tomography in the Trauma Emergency Department and Its Association with Length-of-Stay," Clinical Radiology (2026), as reported by Radiology Business. Figures are rounded as reported.