65 © Springer International Publishing AG, part of Springer Nature 2018 A. Kelly et al. (eds.), Evidence-Based Emergency Imaging, Evidence-Based Imaging, https://doi.org/10.1007/978-3-319-67066-9_6 Pediatric Accidental Traumatic Brain Injury: Evidence-Based Emergency Imaging Nadja Kadom, Enrique Alvarado, and L. Santiago Medina N. Kadom (*) Children’s Healthcare of Atlanta (Egleston), Atlanta, GA, USA Emory University School of Medicine, Atlanta, GA, USA Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA, USA e-mail: nkadom@emory.edu E. Alvarado Department of Diagnostic Radiology, Puerto Rico Children’s Hospital, Bayamón, Puerto Rico e-mail: neuropedrad@gmail.com L.S. Medina Nicklaus Children’s Hospital, Miami Children’s Health Systems, Miami, FL, USA Florida International University, Herbert Wertheim College of Medicine, Miami, FL, USA e-mail: Santiago.medina@mch.com 6 Definitions and Pathophysiology The definition of TBI used by the Centers for Disease Control is a disruption in the normal function of the brain that can be caused by a bump, blow, or jolt to the head or a penetrating head injury [1]. The pathomechanism in TBI relates to primary and secondary brain injury. Primary brain injury refers to effects that result directly from transfer of external mechanical forces to the contents of the brain. These include diffuse axonal injury (Fig. 6.2a–c), focal contusions (particularly in frontal and temporal lobes), and extra-axial hemorrhages (epidural, subdural, subarachnoid) (Fig. 6.3) [2]. Secondary brain injury is the result of a cascade of molecular mechanisms that are Key Points • The PECARN decision rule can help identify children in whom imaging after TBI is unnecessary (strong evidence). • In the acute TBI setting, CT is the imag- ing modality of choice because of avail- ability, speed, and importance in deciding emergent neurosurgical approach (moderate evidence). • MRI is the preferred imaging modality in children with TBI who need additional imaging and in children with subacute or chronic TBI (moderate evidence). • Advanced neuroimaging techniques are emerging as a potential tool for diagno- sis, to guide management and to predict prognosis in pediatric patients with TBI (limited or insufficient evidence).