Computed tomography brain scan utilization in patients with headache presenting to emergency departments: a multinational study.

Background And Importance: Recommended indications for emergency computed tomography (CT) brain scans are not only complex and evolving, but it is also unknown whether they are being followed in emergency departments (EDs).

Objective: To determine the CT utilization and diagnostic yield in the ED in patients with headaches across broad geographical regions.

Design: Secondary analysis of data from a multinational cross-sectional study of ED headache presentations over one month in 2019.

Setting And Participants: Hospitals from 10 participating countries were divided into five geographical regions [Australia and New Zealand (ANZ); Colombia; Europe: Belgium, France, UK, and Romania; Hong Kong and Singapore (HKS); and Turkey). Adult patients with nontraumatic headache as the primary presenting complaint were included. Patients were identified from ED management systems.

Outcome Measures And Analysis: The outcome measures were CT utilization and diagnostic yield. CT utilization was calculated using a multilevel binary logistic regression model to account for clustering of patients within hospitals and regions. Imaging data (CT requests and reports) were sourced from radiology management systems.

Main Results: The study included 5281 participants. Median (interquartile range) age was 40 (29-55) years, 66% were women. Overall mean CT utilization was 38.5% [95% confidence interval (CI), 30.4-47.4%]. Regional utilization was highest in Europe (46.0%) and lowest in Turkey (28.9%), with HKS (38.0%), ANZ (40.0%), and Colombia (40.8%) in between. Its distribution across hospitals was approximately symmetrical. There was greater variation in CT utilization between hospitals within a region than between regions (hospital variance 0.422, region variance 0.100). Overall mean CT diagnostic yield was 9.9% (95% CI, 8.7-11.3%). Its distribution across hospitals was positively skewed. Regional yield was lower in Europe (5.4%) than in other regions: Colombia (9.1%), HKS (9.7%), Turkey (10.6%), and ANZ (11.2%). There was a weak negative correlation between utilization and diagnostic yield ( r  = -0.248).

Conclusion: In this international study, there was a high variation (28.9-46.6%) in CT utilization and diagnostic yield (5.4-11.2%) across broad geographic regions. Europe had the highest utilization and the lowest yield. The study findings provide a foundation to address variation in neuroimaging in ED headache presentations.