Acute Neuroimaging Findings Are Associated with Poor Outcome after Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Previous studies have failed to determine whether acute neuroimaging findings after mild traumatic brain injury (mTBI) are associated with poor outcomes. We performed a systematic review and meta-analysis to determine whether such indicators are associated with health outcomes, recovery-related outcomes, or concurrent indicators of injury severity. We searched MEDLINE, PsycINFO, and Web of Science in April 2024. We extracted data from prospective studies or retrospective analyses of prospective data, where computed tomography scans were acquired within 1 week of mTBI or magnetic resonance imaging scans were acquired within 3 months of injury, according to PRISMA guidelines. The primary outcome measure was the Glasgow Outcome Scale. Secondary outcomes and indicators of injury severity included self-reported loss of consciousness, post-traumatic amnesia, and post-concussion symptom scores. The protocol for this study was pre-registered (PROSPERO #CRD42020190659). We included 64 studies in the review and 25 studies in the meta-analyses. The presence of acute neuroimaging findings after mTBI was associated with higher odds of poor outcome (OR = 2.04 [1.29-3.24], <i>p</i> = 0.0024, <i>k</i> = 7, <i>n</i> = 2,947) and loss of consciousness (OR = 1.42 [1.02-1.97], <i>p</i> = 0.039, <i>k</i> = 15, <i>n</i> = 3,912) compared to those without acute neuroimaging findings, but not post-traumatic amnesia (OR = 1.27 [0.65-2.49], <i>p</i> = 0.49, <i>k</i> = 10, <i>n</i> = 5,155) or post-concussion symptoms (Hedge's <i>g</i> = 0.00 [-0.17-0.17], <i>p</i> = 0.97, <i>k</i> = 9, <i>n</i> = 3,616). Results from qualitative analysis of outcome data that could not be synthesized quantitatively are congruent. Acute neuroimaging findings after mTBI are associated with poor functional outcome and may be clinically relevant for identifying patients at a higher risk for poor outcomes.