Focal Lesions in Acute Mild Traumatic Brain Injury and Neurocognitive Outcome: CT versus 3T MRI

TLDR

Mild traumatic brain injury is linked to long‑term cognitive deficits. The study aimed to compare the detection rate of acute post‑traumatic focal lesions on CT versus 3T MRI and their association with neurocognitive outcomes. A prospective cohort of 36 adults with single mTBI underwent CT within 24 h and 3T MRI within 2 weeks, with scans reviewed by blinded neuroradiologists, and 28 patients plus 18 matched controls completed serial neurocognitive testing. 3T MRI identified parenchymal lesions in 75 % of patients—higher than CT—but neither modality correlated with working‑memory impairment, suggesting that advanced techniques such as diffusion tensor imaging may be required to find biomarkers for neurocognitive outcomes.

Abstract

Mild traumatic brain injury (mTBI) is associated with long-term cognitive deficits. This study compared the detection rate of acute post-traumatic focal lesions on computed tomography (CT) and 3T (Tesla) magnetic resonance (MR) imaging with neurocognitive outcomes. Adults (n = 36; age range, 19-52 years) with a single episode of mTBI (Glasgow Coma Scale 13-15, as well as loss of consciousness and post-traumatic amnesia) were prospectively enrolled and had CT within 24 h of injury and 3T MR within 2 weeks of injury. The CT and MR scans were reviewed by two neuroradiologists who were blinded to clinical information. Twenty-eight of these mTBI subjects and 18 matched healthy volunteers also underwent serial neurocognitive testing. Of the 36 mTBI cases, intraparenchymal lesions were detected in 18 CT and 27 acute MR exams, consisting of hemorrhagic traumatic axonal injury (TAI) (eight CT, 17 MR), non-hemorrhagic TAI (zero CT, four MR), and cerebral contusions (13 CT, 21 MR). Mild TBI patients had significantly worse performance on working memory tasks than matched controls at the acute time point (<2 weeks), and at 1 month and at 1 year post-injury; yet there was no significant correlation of imaging findings with working memory impairment. In conclusion, 3T MR detected parenchymal lesions in 75% of this mTBI cohort with loss of consciousness and post-traumatic amnesia, a much higher rate than CT. However, the CT and 3T MR imaging findings did not account for cognitive impairment, suggesting that newer imaging techniques such as diffusion tensor imaging are needed to provide biomarkers for neurocognitive and functional outcome in mTBI.