Imaging of Head Trauma

Abstract

Head trauma is a common cause of emergency room visits, and traumatic brain injury (TBI) accounts for approximately 1.4million emergency department visits per year in the United States. The scope of head trauma also includes calvarial, facial, and skull base trauma. The role of the emergency radiologist is to help identify who might benefit from imaging, to determine which imaging protocols to use, and to provide efficient and accurate interpretation of imaging studies. This article reviews these topics, focusing on practical applications. Computed tomography (CT) is the primary imaging modality used in the emergency department for the evaluation of head trauma. Although some centers use radiography for the evaluation of maxillofacial fractures, in most cases CT is the imaging study of choice to evaluate facial trauma, and CT is superior to radiography for the evaluation of skull base trauma, detecting previously unsuspected fractures. Contrast is used to evaluate for vascular injury, as discussed in the next chapter, but does not play a role in the diagnosis of traumatic brain lesions or fractures. Magnetic resonance imaging (MRI) may play a role in problem solving in the emergency department, but generally is not used for primary diagnosis in head trauma as it is more costly, more time consuming, and less well-tolerated by critically ill patients who may be undergoing intensive monitoring. Whereas conventional MRI is more sensitive than CT for detecting traumatic lesions in patients sustaining mild TBI, these findings were not correlated with neurocognitive outcome, and the utility of obtaining early MRI in this setting has not been validated. Advanced MRI techniques such as diffusion tensor imaging may play a role in predicting outcome, and functional MRI may also play a role in demonstrating sequela of mild TBI but much active research is still ongoing in this area.