Introduction: Computed tomography (CT) is routinely performed in traumatic brain injury (TBI). Magnetic resonance imaging (MRI) is considered more sensitive than CT for subtle abnormalities. Because CT does not always explain the posttraumatic neurologic examination, MRI is being performed with increasing frequency. Although MRI at a later stage may be of significant prognostic value, the role of early MRI is questionable. Our objective was to evaluate the role of early MRI in the initial management of patients with TBI.
Methods: This is a 3-year prospective study (January 2005-December 2007) of adult patients with TBI who, in addition to CT, had MRI of the head within 48 hours of admission to the hospital. The findings from the two imaging studies were compared. The outcome was any change in management based on MRI findings.
Results: We identified 123 trauma patients who had MRI within 18 hours +/- 14.5 hours of CT (median: 12 hours). In 82 (67%) patients, the findings of CT and MRI were identical. In the remaining 41 patients there were discrepancies between CT and MRI: 35 patients had slight differences in the location or size of the lesions found and six had minor brain lesion detected by MRI and not CT. Compared with patients who had identical CT and MRI, those who showed differences in the two tests had higher severity of head injury, lower initial blood pressure, and a higher rate of intubation. Based on CT findings, 78 (63%) patients received TBI-related interventions: 8 craniotomies, 12 intracranial pressure monitoring catheters, 14 mannitol infusions, and 72 antiepileptic medications. There was no change in treatment because of MRI.
Conclusion: Early MRI may be superior to CT in describing subtle TBI findings, but this information does not affect management. Head CT is the only imaging test necessary in the first 48 hours after TBI.