Teaching Case

A 56 years old female that suddenly fell down with no pulse.

A 56 years old female suddenly fell down while she was at home, had no pulse. The ambulance tried to resuscitate and then brought the patient to the emergency department. A neuro-CT was perormed and there it showed an inversion of the normal attenuation relationship between grey and white matter; grey matter is of relatively lower attenuation than adjacent white matter (Fig. 1, 2).

Hypoxic-ischemic injury to the brain is a devastating occurrence that frequently results in death or profound long-term neurologic disability in both children and adults. CT features of the reversal sign are diffusely decreased density of cerebral cortical grey and white matter with a decreased or lost grey/white matter interface, or reversal of the grey/white matter densities and relatively increased density of the thalami, brainstem, and cerebellum.
The reversal sign indicates diffuse cerebral injury in a patient who has suffered an anoxic insult. Causes of the reversal sign include head trauma, hypoxia, birth asphyxia, drowning, status epilepticus, hypothermia, bacterial meningitis, strangulation, nonaccidental trauma, and other causes of global cerebral ischemia. When other causes have been excluded, demonstration of intracranial blood in the presence of the reversal sign should be considered an indicator of nontraumatic injury. The reversal sign is associated with a poor prognosis and indicates irreversible brain damage. Mortality rates are high in children whose CT images show the reversal sign (35%), and those who survive have profound neurologic deficits with severe developmental delay.