Trends and Factors Affecting High-Dose (≥50 mSv) Computed Tomography Scans in the Emergency Department: A Four-Year Analysis.
Level 4 - case-series / case-control
Retrospective single-center observational cohort study without a control comparator
PubMed 40651301 · doi:10.1016/j.jemermed.2025.05.024
What was done
Researchers conducted a retrospective cohort study at a single tertiary care emergency department analyzing adult CT scans performed between 2019 and 2022. They identified single-examination CT scans delivering a radiation dose of ≥50 mSv and evaluated variations across patient age, sex, scan type, scanner model, contrast use, and examination year using descriptive statistics and Kruskal-Wallis tests.
What was found
Out of >166,000 CT scans, 1,357 (0.81%) delivered doses ≥50 mSv. Patients receiving these scans were 58% female and 61% under 65 years old. The most frequent high-dose scans were aorta protocols (62%) and chest/abdomen/pelvis scans (14%), while IV contrast was used in 89% of cases. The highest median doses were observed in extremity CTs (67 mSv), aorta scans (60 mSv), and chest/abdomen/pelvis studies (59 mSv). The proportion of high-dose scans increased from 0.50% in 2019 to 0.92% in 2022, alongside an increase in median dose from 57 mSv to 60 mSv. Dose variations were statistically significant across scan types, patient age, contrast use, and year, but not across patient sex or scanner model.
Why it matters
Despite advances in CT technology aimed at dose reduction, high-radiation ED scans nearly doubled in proportion over four years. Identifying specific high-dose scan types—mainly aortic and extremity protocols—highlights clear targets for protocol optimization to reduce cumulative radiation exposure in emergency patients.
Limits
The study is limited by its retrospective, single-center design, which may reflect local protocol choices rather than broader emergency medicine practice. Clinical indications, patient body mass index, cumulative lifetime radiation exposure, and subsequent clinical outcomes or malignancy rates were not evaluated.
Cited by
- supports Radiation exposure exceeding 50 millisieverts per year is generally established to increase the risk of mutagenesis.