Moderate and severe traumatic brain injury: lesion frequency distribution maps and prognostic importance of brain contusions on early MRI.

Abstract

Objective: Brain contusion frequency, distribution and prognostic value were investigated on early MRI in moderate-severe traumatic brain injury (TBI).

Materials and methods: We prospectively included 301 patients (8-70 years) admitted to Trondheim or Oslo University Hospitals with moderate (n = 123) or severe (n = 178) TBI and brain contusion(s) on MRI within 6 weeks (median 9 days) post-injury. Volumetric segmentation of brain contusions was performed manually on fluid-attenuated inversion recovery (FLAIR) MRI. The segmentations were combined into lesion frequency distribution maps for the whole cohort, moderate and severe TBI separately and three outcome categories. The 12-month outcome was assessed with the Glasgow Outcome Scale-Extended (GOSE). Relationship with the outcome was evaluated visually, with adjusted analyses and with voxel-based lesion-symptom mapping (VLSM).

Results: The frontal (75%) and temporal (82%) lobes had the highest frequency of brain contusions. There was no significant difference in total lesion volume between moderate and severe TBI (median: moderate TBI 15.8 cm³, severe TBI 13.6 cm³, p = 0.30). The total brain contusion volume significantly predicted the 12-month outcome in the adjusted models and decreased with increasing outcome category (GOSE score 1-4, median volume: 37.8 cm³; GOSE score 5-6, median volume: 14.5 cm³; GOSE score 7-8, median volume: 7.1 cm³; p = 0.02). There was no significant association between lesion location and the GOSE score in the VLSM analyses.

Conclusion: In this MRI cohort study, we found similar distributions and volumes of brain contusions in moderate-severe TBI. The brain contusion volume significantly predicted the 12-month outcome, whereas the lesion location was not associated with the outcome.

Key points: Question Accurate prognostic models for TBI are important for clinical decision making, but the value of including MRI measures remains unclear. Findings In moderate and severe TBI, brain contusions had the highest frequency in frontotemporal regions. Contusion volume predicted 12-month functional outcome, whereas there was no association with location. Clinical relevance Our findings indicate that brain contusion volume is more important for functional outcomes than lesion location. The brain contusion volume should be included in future AI models as one predictor of patient outcome after TBI.