The effect of COVID-19 on emergency department imaging: what can we learn?

Purpose: To investigate the effect of the COVID-19 pandemic on emergency department (ED) imaging.

Methods: This retrospective study included all ED visits at a four-hospital academic health system in two matched 5-week periods. Demographic information, COVID-19 status, and disposition were reviewed. Type of imaging, acquisition time, and radiology reports were analyzed. Significance level was set at p < 0.05.

Results: A 43.2% decrease in ED visits and 12% reduction in overall ED imaging occurred during the pandemic period. Mean age was unchanged, but a shift in gender and racial characteristics was observed (p < 0.001). In the pandemic period, COVID-19 ED patients were older (61.8 ± 16.9 years, p < 0.001) and more likely to be Black (64.2%; p < 0.001) than non-COVID-19 patients. Imaging per ED encounter increased to 2.4 ± 2.8 exams from 1.7 ± 1.1 (p < 0.001). Radiography increased (57.2% vs. 52.4%) as a fraction of total ED imaging, while computed tomography (23.4% vs. 27.2%) and ultrasound (8.5% vs. 9.6%) decreased (pre-pandemic vs. pandemic). COVID-19 ED patients underwent CT and US at a lower rate (11.5% and 5.4%) than non-COVID-19 patients (25.4% and 9.1%). The proportion of imaging study reports concluding "no disease" or "no acute disease" decreased from 56.7 to 40.6% (p < 0.001).

Conclusion: The COVID-19 pandemic led to a significant reduction in ED visits, a shift in patient demographics, and a significant decrease in imaging volume. Additional impact included a significant increase in the proportion of positive imaging studies.