Critical Care Registered Nurse (CCRN) Practice Exam

What imaging findings are common in patients with diffuse axonal injury?

1. Visible hemorrhage in the CT scan

2. Localized mass lesions

3. Shearing of brain tissue on MRI

4. Calcifications in the basal ganglia

The correct answer is: Shearing of brain tissue on MRI

In diffuse axonal injury (DAI), the hallmark imaging findings are characterized by shearing of brain tissue. This type of injury results from acceleration-deceleration forces, causing widespread damage to axons throughout the brain. When evaluated using MRI, one can observe specific patterns indicative of DAI, such as lesions in the white matter and at the junctions of gray and white matter, which are not typically seen on CT scans. MRI is particularly sensitive in detecting the microstructural changes and subtle areas of injury, including the presence of small lesions caused by disrupted axonal integrity. Recognizing these sheared axons is crucial, as it aids in diagnosing the extent of the injury and informing prognosis. Thus, the identification of shearing on MRI is a key finding in patients suspected of having diffuse axonal injury.