Global diagnostic accuracy and prognostic value of non-contrast CT in acute traumatic brain injury: a systematic review and meta-analysis.

BACKGROUND: Traumatic brain injury (TBI) is a global health challenge associated with high morbidity and mortality. Non-contrast computed tomography (NCCT) remains the first-line imaging modality due to its accessibility and speed, yet its diagnostic and prognostic utility across diverse populations remains underexplored. PURPOSE: To systematically evaluate and quantify the diagnostic accuracy and prognostic value of NCCT in acute TBI patients worldwide. EVIDENCE ACQUISITION: Following PRISMA 2020 guidelines, a systematic literature search was conducted in PubMed, Embase, Cochrane Library, and Scopus up to April 2025. Studies assessing the diagnostic or prognostic performance of NCCT in acute TBI were included. QUADAS-2 was used for quality assessment. Meta-analyses were performed using random-effects models. EVIDENCE SYNTHESIS: Out of 2,132 articles screened, 41 studies met inclusion criteria, encompassing over 76,000 patients. The pooled sensitivity and specificity for NCCT detecting intracranial hemorrhage were 0.92 (95% CI: 0.89-0.95) and 0.87 (95% CI: 0.82-0.91), respectively. Prognostically, features like midline shift > 5 mm and compressed basal cisterns showed a significant association with in-hospital mortality (OR: 3.6, 95% CI: 2.4-5.1). Subgroup analyses by age, GCS, and scan timing confirmed robust diagnostic consistency. CONCLUSION: NCCT demonstrates high diagnostic accuracy in detecting intracranial hemorrhage and offers substantial prognostic insights in acute TBI. It remains a cornerstone imaging tool, particularly valuable in time-sensitive emergency settings. CLINICAL IMPACT: NCCT should be prioritized in emergency protocols for early diagnosis and risk stratification in TBI, particularly in resource-constrained environments lacking advanced neuroimaging.