Short Article

The Growing Role of MR in Evaluating Pediatric Head Trauma

Traumatic brain injury (TBI) is a leading cause of death and disability in children and a serious public health issue with significant socioeconomic consequences.Although most head injuries are classified as mild, it's estimated that 10 to 15 percent of children sustain a severe intracranial injury following head trauma.2 Even among those children who present in the emergency department without any initial symptoms suggestive of TBI, the long-term effects of an untreated TBI can have devastating consequences for neurocognitive functioning and psychosocial behavior.1 Given the potential toll of a TBI, the earlier intracranial injuries are diagnosed, the more likely the appropriate interventions can be put into place and the outcomes potentially improved.1,2,3

Modalities for assessing head injury in children

Although the Glasgow Coma Scale has been the traditional means of classifying TBI severity, computed tomography (CT) imaging is the preferred modality for the evaluation of TBI in the ED based on its widespread availability, that it can be completed quickly and doesn't require sedation; it also has the ability to accurately identify lesions, such as fracture or acute hemorrhage, that may warrant emergency neurosurgery.1,2

But recently there has been a growing awareness within the medical community of an increased theoretical cancer risk from head CT examinations performed in children younger than 15 years of age, particularly in minor head injuries, in which the risks of CT may outweigh the potential benefits.2,3 

Because of that, magnetic resonance imaging (MRI) is increasingly becoming an alternate to CT scans, particularly as multiple studies continue to report that MR demonstrates greater sensitivity in the detection of most types of head injuries, with greater anatomic detail of brain parenchyma—the functional tissue in the brain that if damaged, may result in a loss of cognitive ability or even death—without radiation the exposure of CT imaging.2,3

In one recent retrospective study of five hundred pediatic patients in which 78 percent had mild TBI, it was found that MR detected a greater number of intraparenchymal lesions, 34 percent, compared to CT, which picked up 15 percent.2 Among patients with abusive head trauma (AHT), MRI detected intraparenchymal lesions in 43 percent of patients, compared with only 4 percent that CT detected. Further, among eight children who had a normal CT scan, six were found to have abnormal lesions on an MR exam.2

In another study, it was concluded that MRI had greater sensitivity in the detection of most types of head injuries, in comparison to CT, with the exception of skull fractures.1 This extensive analysis of the literature on pediatric head trauma, TBI, and imaging in head trauma also detailed several key points regarding the unique ability of MRI in providing additional clinical information compared to CT exams in sub-acute and chronic TBI, which may be especially important in imaging older injuries in AHT, as well as imaging acute injuries, such as intracranial hemorrhage and parenchymal injuries, which may help in guiding treatment and predicting clinical outcomes.1

The case for MR as the initial imaging modality in pediatric head trauma

Numerous recent studies have demonstrated the important role of MR in evaluating pediatric head injury in the acute setting as well as the sub-acute evaluation of TBI. In all instances, the studies have shown MR’s sensitivity in providing critical information that is not delineated on CT, as well as decreasing radiation exposure and the theoretical cancer risk in children.1,2,3

Currently, CT remains the most common imaging modality in evaluating head injuries in children due to its widespread availability in hospital EDs, as well as issues around the cost of MR, the possible need for sedation, and access to trained MR personal.1 Yet, MRI continues to demonstrate a vital, if not superior, role in the detailed evaluation of head injuries and TBI in children. Further studies, including the use of rapid-sequence MR imaging, are clearly warranted in order to determine the potential role for MR as the initial imaging modality in pediatric head trauma.1,3

  

References

  1. MRI Brain Imaging in Assessment of Pediatric Head Trauma, Radiol Open J. March, 2019. https://openventio.org/wp-content/uploads/MRI-Brain-Imaging-in-Assessment-of-Pediatric-Head-Trauma-ROJ-3-121.pdf Accessed September 12, 2019.
  2. Computed Tomography Vs Magnetic Resonance Imaging for Identifying Acute Lesions in Pediatric Traumatic Brain Injury, Hospital Pediatrics, © The American Academy of Pediatrics, 2015. https://www.researchgate.net/publication/272083348_Computed_Tomography_Vs_Magnetic_Resonance_Imaging_for_Identifying_Acute_Lesions_in_Pediatric_Traumatic_Brain_Injury Accessed September 12, 2019.
  3. Minimizing Radiation Exposure in Evaluation of Pediatric Head Trauma: Use of Rapid MR Imaging, AJNR Am J Neuroradiol, January 2016. http://www.ajnr.org/content/37/1/11.long Accessed September 12, 2019.