Fast MRI for Pediatric Traumatic Brain Injury: What Findings Are Missed Compared with Routine MRI?

BACKGROUND AND PURPOSE: Traumatic brain injury (TBI) is a frequent indication for neuroimaging in young children. Head CT is widely available and fast, but it exposes children to ionizing radiation. Routine MRI avoids radiation but is longer and frequently requires sedation. Fast MRI without sedation is increasingly used instead of head CT in young children with head trauma, but the intracranial findings it may miss relative to routine MRI are not well defined. MATERIALS AND METHODS: We retrospectively studied children 6 years of age or younger who underwent fast brain MRI for evaluation of TBI and subsequent routine brain MRI within 7 days from 2014 through 2024. Reports were abstracted for traumatic intracranial findings. To address selection bias of the paired cohort, we also identified children who underwent fast MRI as their initial neuroimaging study for evaluation of TBI who did not undergo a subsequent routine MRI within 7 days. We reviewed any return emergency department or inpatient visits within 1 year of the initial fast MRI for evidence of a missed traumatic brain injury. RESULTS: The selected paired cohort included 69 children; 68 had traumatic intracranial findings on routine MRI. Fast MRI detected at least one traumatic intracranial abnormality in all 68 routine-MRI-positive cases. Compared with routine MRI, fast MRI was less sensitive for SAH (18/24, 75.0%) and parenchymal injury (20/31, 64.5%). Among 2471 children with an initially negative fast MRI, 1,122 re-presented to the emergency department or inpatient setting within one year. Four had traumatic findings on follow-up neuroimaging, all attributed to new trauma rather than delayed recognition. CONCLUSIONS: In this selected cohort, fast MRI detected traumatic brain injury consistently, while selected components were apparent only on routine MRI. Fast MRI may serve as an initial screening and triage examination in hemodynamically stable children when skull fracture detection or complete forensic characterization is not needed.