Head CT in Adult Mild Traumatic Brain Injury: A Global Review of Indications and Decision Rules

Mild traumatic brain injury (mTBI) in adults is extremely common worldwide, but only a small fraction of these patients harbor clinically significant intracranial injuries. Computed tomography (CT) of the head is the standard diagnostic tool to detect traumatic brain hemorrhages or lesions, yet indiscriminate CT scanning of all mTBI patients is inefficient, costly, and exposes patients to ionizing radiation. To optimize patient care, numerous clinical decision rules and guidelines have been developed internationally to identify which adult patients with mTBI should undergo head CT. This review provides a global perspective on the indications for head CT in adult mTBI, comparing key decision rules including the Canadian CT Head Rule, New Orleans Criteria, UK NICE Head Injury Guidelines, and others. Methods: We conducted a comprehensive analysis of major international guidelines and decision rules for head CT in adult mTBI, focusing on their inclusion criteria, risk factors, and diagnostic performance. Results: All the examined rules prioritize near-100% sensitivity for identifying patients who need neurosurgical intervention, but they differ greatly in specificity and recommended CT utilization rates. North American rules such as the New Orleans Criteria tend to favor higher sensitivity, scanning almost all patients with any symptom, whereas the Canadian CT Head Rule and certain European guidelines (NICE, Scandinavian) are more selective, significantly reducing CT usage while maintaining safety. Discussion: We discuss how these variations reflect different healthcare settings and risk tolerances, and we examine the implications for neurosurgical practice. We also highlight challenges in guideline implementation, the impact on global CT utilization, and emerging approaches (such as biomarker-assisted triage) that may further refine decision-making. In conclusion, appropriate use of clinical decision rules for head CT in mTBI can safely minimize unnecessary imaging, but local adaptation and clinician judgment remain crucial to ensure that no significant injuries are missed while avoiding over-scanning.