Age- and Region-Stratified Growth in Emergency Department Neuroimaging Utilization within Epic Cosmos, 2016–2025

BACKGROUND: Emergency department (ED) neuroimaging utilization has reportedly increased over the past decade, but whether this growth is concentrated among a specific age range or specific geographic regions remains less well characterized. The present study aimed to address this gap using the data from participating Epic Cosmos healthcare organizations across the United States. MATERIALS AND METHODS: We analyzed deidentified aggregate data for ED encounters captured within participating healthcare organizations between January 2016 and December 2025. Annual aggregate volumes were extracted for 16 neuroimaging examination categories. Encounter-adjusted utilization rates per 1,000 ED encounters were calculated and stratified by age and U.S. Census region with temporal trends assessed using Poisson log-linear regression. RESULTS: Total neuroimaging utilization increased across all age groups from 2016 to 2025, from 21.9 to 33.5 examinations per 1,000 ED encounters in children younger than 5 years and from 377.5 to 592.6 per 1,000 ED encounters in adults aged 65 years or older. The absolute rate difference was largest among adults aged 65 years or older (+215.1 per 1,000 ED encounters) and smallest among children younger than 5 years (+11.7 per 1,000 ED encounters). Utilization also increased across all U.S. Census regions, from 174.1 to 313.4 in the South, 167.5 to 318.4 in the Midwest, 159.7 to 322.0 in the Northeast, and 193.8 to 304.0 per 1,000 ED encounters in the West. Regional absolute rate differences ranged from +110.2 per 1,000 ED encounters in the West to +162.3 in the Northeast. Formal temporal trend analysis confirmed increasing encounter-adjusted utilization across all age groups and regions, with annual incidence rate ratios ranging from 1.048 to 1.059 across age strata and from 1.050 to 1.071 across regions; all p-values for trend were <.001. CONCLUSION: Within the evolving Epic Cosmos network, ED neuroimaging utilization varied by patient age and region from 2016 to 2025, but increased consistently across all evaluated age and geographic strata rather than being limited to older adults or a specific region. However, the magnitude of increase was greater among older adults and varied modestly by region. These utilization patterns may inform neuroradiology staffing, training, scanner allocation, and imaging stewardship initiatives.