# Timing of Magnetic Resonance Imaging (MRI) in Moderate and Severe TBI: A Systematic Review

## TL;DR

This study reviews when to use MRI for moderate and severe traumatic brain injury, finding that early scans within 72 hours may provide better prognostic insights than later ones.

## Contribution

The paper systematically reviews MRI timing in TBI, highlighting early MRI's potential for improved prognostication in ICU patients.

## Key findings

- Early MRI within 72 hours post-injury shows better prognostic value than later scans.
- Diffusion tensor imaging (DTI) between 48 to 72 hours captures critical brain changes.
- Bilateral traumatic axonal injury in brainstem or thalami on MRI predicts outcomes in severe TBI.

## Abstract

Background: Traumatic brain injury (TBI) remains a significant global health concern with a substantial socioeconomic impact. Although computed tomography (CT) is the primary initial neuroimaging technique, magnetic resonance imaging (MRI) offers a superior detection of subtle brain injuries. However, the ideal timing for MRI in critically ill patients with TBI remains unclear. Methods: This systematic literature review focused on the timing and utility of MRI in moderate and severe TBI in the early treatment phase. A comprehensive search was conducted using PubMed, employing specific search terms related to MRI timing and prognostication in TBI. The mean duration from admission to first MRI was examined in the conducting medical center for reference. Results: Early MRI, within 72 h post-injury, demonstrated a prognostic value compared with later scans. Diffusion tensor imaging (DTI) performed within 48 to 72 h captured critical pathophysiological changes. The presence of bilateral traumatic axonal injury in the brainstem or thalami on MRI served as a significant predictor of outcome in severe TBI. In pediatric TBI, most institutions performed MRI between seventy-two hours and two weeks post-injury, highlighting variability in practices. The mean interval until the first MRI at the conducting center was 16 days. Conclusions: MRI appears to be a valuable tool for prognostication in moderate to severe TBI, offering additional insights beyond those provided by CT. However, the optimal timing and modality for accurate diagnostic and prognostic utility remain uncertain. Current evidence suggests that MRI performed within 72 h after injury in ICU-treated patients with moderate and severe TBI offers valuable prognostic insights compared with delayed MRI, although further research is needed to establish standardized timing protocols and confirm the clinical impact.