Which statement best characterizes the CT findings of diffuse axonal injury (DAI)?

Which statement best characterizes the CT findings of diffuse axonal injury (DAI)?

• A. CT often shows few early abnormalities, with possible small petechial hemorrhages in white matter tracts
• B. CT shows large mass effect and midline shift in most cases
• C. CT reveals widespread calcifications in the basal ganglia
• D. CT typically demonstrates hyperdensity in the gray-white matter junction

Answer: (D)

Diffuse axonal injury comes from rapid acceleration-deceleration that shears axons at the gray–white matter interfaces. On CT, the acute hallmark is tiny hemorrhages along these interfaces, seen as hyperdense foci at the gray–white junction. CT can be normal early, but when abnormalities are present, this pattern of microhemorrhages best reflects the underlying injury rather than a focal mass or diffuse edema. Large mass effect or midline shift suggests a bulky hematoma, while basal ganglia calcifications are not typical of acute DAI. MRI is more sensitive, but the hyperdense gray–white junction foci on CT are the best single CT descriptor of DAI.

Diffuse axonal injury comes from rapid acceleration-deceleration that shears axons at the gray–white matter interfaces. On CT, the acute hallmark is tiny hemorrhages along these interfaces, seen as hyperdense foci at the gray–white junction. CT can be normal early, but when abnormalities are present, this pattern of microhemorrhages best reflects the underlying injury rather than a focal mass or diffuse edema. Large mass effect or midline shift suggests a bulky hematoma, while basal ganglia calcifications are not typical of acute DAI. MRI is more sensitive, but the hyperdense gray–white junction foci on CT are the best single CT descriptor of DAI.