Trauma Radiology: Part IV. Imaging of Acute Craniocerebral Trauma

Abstract

Diagnostic imaging has a key role in diagnosis and management of patients sustaining craniocerebral injuries from trauma. We review the current role of skull radiography, computed tomography (CT), and magnetic resonance (MR) in imaging patients sustaining craniocerebral trauma, and we describe the appearance of major forms of pathology as depicted by each modality. CT scan is used to assess quickly the extent of injury and to triage patients to observation, medical, or neurosurgical management. CT findings can be divided into primary craniocerebral injuries, including skull fractures; extraaxial hematomas (subdural and epidural); intraparenchymal injury, such as hematoma, contusion, and diffuse axonal shearing; and intraventricular or subarachnoid hemorrhage. Secondary manifestations of injury, such as cerebral edema and herniation, are also identified, and their course can be followed by serial CT. CT is crucial in assessing the outcome of surgical intervention and in identifying potential delayed complications of either head trauma or surgical intervention, including infection, delayed hemorrhage, cerebral infarction, and tension pneumocephalus. In recent years, MRI has been shown to be valuable in diagnosing cerebral injury. MRI has generally been shown to have greater overall accuracy than CT in identifying and characterizing most forms of traumatic cerebral pathology, but it is less accurate at demonstrating subarachnoid hemorrhage acutely, pneumocephalus, and calvarial fractures, particularly those involving the skull base. Moreover, MRI is still more difficult to perform than CT in critically ill patients, and it is generally far more time-consuming. However, MRI is unequivocally more accurate than CT at revealing certain lesions, particularly brainstem contusion, diffuse axonal shearing, predominantly nonhemorrhagic contusions, and thin collections of blood adjacent to bone, and it should be used selectively when these injuries are suspected.

Agreement of Magnetic Resonance Imaging With Computed Tomography in the Assessment for Acute Skull Fractures in a Canine and Feline Cadaver Model

“…The results of this study confirmed our hypotheses that (1) MRI would have high agreement (93.5%) with CT in the assessment for presence or absence of acute skull fractures in a canine and feline cadaver model, and (2) that there would be no statistically difference between dogs and cats. While CT has traditionally been the modality of choice for the initial assessment of acute head trauma and traumatic brain injury in people, MRI is preferred in many cases of subacute and chronic head trauma and for improved visualization, especially of brain parenchymal nonhemorrhagic lesions (15,(26)(27)(28)(29). Several studies have compared MRI to CT in human head trauma patients.…”

Imaging of Intracranial Hemorrhage

“…Traumatic SAH is the most commonly encountered form of traumatic ICH [ 6 , 7 ]. SAH occurs when there is arterial or venous injury to the vessels coursing through the subarachnoid space overlying the brain parenchyma, and is identified on CT as an abnormal hyperdensity in the subarachnoid space.…”

“…Subdural hematomas are most commonly caused by injury to the venous structures that course deep to the dura mater, and subdural hematomas are less likely to be accompanied by skull fractures [ 6 , 16 ]. Compared to epidural hematomas, subdural hematomas are less likely to be acutely symptomatic due to the slower rate of growth caused by venous injury and the larger lateral extent permitted by the subdural space.…”