often included as part of the initial trauma evaluation.

CTA: CTA is an appropriate modality in the setting of

penetrating neck injury, cervical fracture/subluxation, skull

base fractures that traverse the carotid canal or a dural venous

sinus, and suspected vascular dissections.

MR: MR is generally a secondary modality most often used in

the late acute or subacute stages of brain injury. It is helpful in

detecting focal/regional/global perfusion alterations,

assessing the extent of hemorrhagic and nonhemorrhagic

injuries, and assisting in long-term prognosis. MR should also

be considered if nonaccidental trauma is suspected either

clinically or on the basis of initial CT scan findings.

Who and When to Image?

Liberal use of head CT scans even in minor trauma (normal

neurologic examination, no loss of consciousness) is

increasingly common. Many clinical studies have attempted to

determine whom to image and when. Three major clinically

based appropriateness criteria for imaging acute head trauma

are currently in widespread use. These are: (1) The American

College of Radiology (ACR) Appropriateness Criteria, (2) the

New Orleans Criteria (NOC), and (3) the Canadian Head CT

Rule (CHCR).

The American College of Radiology has delineated and

published updated appropriateness criteria for imaging head

trauma. Emergent NECT in mild/minor CHI with the presence

of a focal neurologic deficit &/or other risk factors is deemed

very appropriate, as is imaging all traumatized children under

2 years of age.

Between 6-7% of patients with minor head injury have

positive findings on head CT scans; most also have headache,

vomiting, drug or alcohol intoxication, seizure, short-term

memory deficits, or physical evidence of trauma above the

clavicles. CT should be used liberally in these cases as well as in

patients over 60 years of age and in children under the age of

2.