Case 100 - Non-accidental trauma: neuroimaging

Summary

Imaging description

Head trauma is the leading cause of child abuse fatality and a major factor in long-term morbidity [1, 2]. It is important to image the brain in all suspected cases of inflicted trauma. This is typically performed with a CT head without contrast, for its ability to detect intracranial hemorrhage, cerebral edema, and skull fractures. MRI is occasionally performed to better characterize extra-axial fluid collections, identify parenchymal infarcts or ischemia in the setting of suffocation, and recognize subtle cases of shear injury [3, 4]. Cranial ultrasound does not play a significant role in the initial neuroimaging evaluation of nonaccidental trauma.

Subdural hemorrhage is the most common intracranial manifestation of inflicted trauma [1]. As in adults, acute subdural blood is hyperattenuating on a non-contrast CT, the result of shear forces tearing bridging cortical veins that drain into the dural venous sinuses. Subdural hemorrhage is non-specific for traumatic injury. Close correlation with available clinical history is warranted when differentiating accidental versus non-accidental trauma. Nonaccidental injury produces hemorrhage that is more frequently bilateral and distant from the site of calvarial fracture, due to shear forces rather than direct coup injury [5]. Acute subdural hemorrhage must also be distinguished from the normal falx cerebri and tentorium cerebelli, which are prominent in infants. The latter are symmetrically dense and thickened on non-contrast CT, while hemorrhage thickens these dural reflections in an asymmetric or nodular fashion [6, 7].