A 4-year-old boy was transferred because of persistently altered mental status (grogginess) after a fall down stairs despite a negative head CT result (Left Panel). Fast MRI (Right panel) identified a small, posterior subarachnoid haemorrhage. Images reproduced from Lindberg et al. Pediatrics doi: 10.1542/peds.2019-0419
Traumatic brain injury (TBI) is a common reason for children to seek emergency care. Despite a relatively low incidence of clinically significant injury in these children, 20% to 70% of them undergo CT examinations, exposing them to ionizing radiation and increased risk of cancer. A recent study (Lindberg DM et al. Feasibility and Accuracy of Fast MRI Versus CT for Traumatic Brain Injury in Young Children. Pediatrics. 2019 Oct;144(4). doi: 10.1542/peds.2019-0419) shows that “fast MRI” “ is effective in identifying traumatic brain injuries in children, and can avoid exposure to ionizing radiation and anesthesia. “We found that fast MRI is a reasonable alternative to CT,” said Dr. D Lindberg, “Nearly all – 99 percent – of fast MRIs were completed successfully, with accuracy that was similar to CT, while avoiding the harms of radiation exposure.”
Conventional MRI can identify injuries without radiation exposure, but requires the child to remain motionless for several minutes. Conventional MRI requires anesthesia, which is not practical in many injured children and may expose them to mild cognitive injury. Fast MRI avoids the need for sedation by using faster, and more motion-tolerant imaging techniques.
Between June 2015 and June 2018, the researchers recruited participants to their study. Children less than six years old who had already undergone CT scans during their emergency care were eligible to participate and those enrolled received fast MRI as soon as possible, usually within 24 hours of the CT scan.
Out of the 225 children enrolled, fast MRI was completed in 223 cases. The median imaging time in fast MRI was 6 minutes, 5 seconds. Fast MRI results matched those of CT in more than 90 percent of cases. CT showed better accuracy for identifying fractures or breaks to the skull, while fast MRI did a better job of imaging the brain and the space between the brain and skull.
One limitation of the study is that it may not apply to other settings without access to cutting-edge MRI scanners or experienced pediatric radiologists. “We were fortunate to be using newer scanning equipment and highly experienced technicians and pediatric radiologists,” Lindberg said. “While we believe our findings reveal a feasible alternative to CTs in pediatric specialty centers, further study is necessary to test the results in other settings.”