Cranial CT utilisation, diagnostic yield and clinical outcomes in mild traumatic brain injury: a retrospective emergency department cohort

Mild traumatic brain injury (mTBI) increasingly affects older adults and frequently prompts cranial computed tomography (CT). We assessed CT utilisation, radiological diagnostic yield and short-term clinical outcomes, and examined factors associated with the decision to perform initial CT. We conducted a retrospective single-centre cohort study of patients aged ≥ 14 years with clinically confirmed mTBI presenting to a Spanish emergency department between January 2019 and January 2022. Radiological outcomes were assessed among patients undergoing CT. Multivariable logistic regression evaluated initial CT utilisation (yes/no) in the full cohort. Among 3,088 patients, 1,636 (53.0%) were aged ≥ 75 years. Initial CT was performed in 2,657 (86.0%); 457 of those imaged (17.2%) had any reported radiological finding, whereas 84 (3.2%) had an acute traumatic intracranial injury. Repeat CT was performed in 562 patients (18.2% of the cohort); progression of existing lesions was documented in 20 (3.6% of repeat scans), and newly detected lesions in six (1.1%). In multivariable logistic regression, age ≥ 75 years (adjusted odds ratio [aOR] 25.79, 95% confidence interval [CI] 15.68–43.60) and anticoagulant treatment (aOR 9.29, 95% CI 3.80–30.73) were strongly associated with initial CT utilisation. Two patients (0.06%) required neurosurgical intervention; 66 (2.1%) were readmitted and three (0.1%) died within 30 days. In this predominantly older mTBI cohort, initial cranial CT utilisation was high, while acute traumatic intracranial injury was identified in 3.2% of those imaged. Older age and antithrombotic treatment were associated with CT utilisation, not independently established predictors of intracranial injury. Diagnostic yield alone cannot determine imaging appropriateness or the safety of omitting CT.