One hard indication for ordering a CTA neck in the setting of trauma is to evaluate for BCVI. BCVI is an occult traumatic injury to the vessels of the neck that carries a high rate of morbidity and mortality if left untreated. In the past, BCVI was often diagnosed after a stroke.
When to suspect it: severe mechanism of injury (high energy, hyperextension/rotation, direct blow to vessels, adjacent bone fractures - C2-C6) coupled with clinical signs - focal neuro deficit or epistaxis after trauma from a suspected arterial source. Traumatic carotid-cavernous fistulas can also develop and lead to orbital pain/proptosis, hyperemia, cerebral swelling, and seizures.
How is it classified: Grades I (intimal irregularity) - V (transection/extrav) .
How is it managed: In general, patients need admission because the injury often does not occur in isolation. Patients need four vessel cerebral angiogram (FVCA) to fully diagnoseanticoagulation and a multidisciplinary approach.
East guidelines (Level II recommendation):
1. Patients presenting with any neurologic abnormality that is unexplained by a diagnosed injury should be evaluated for BCVI.
2. Blunt trauma patients presenting with epistaxis from a suspected arterial source after trauma should be evaluated for BCVI.
3. Duplex ultrasound is NOT a useful screening tool, FVCA is the gold standard diagnostic imaging modality.
Who should be screened (Level III recommendation)? LeFort fx, C-spine fx, Petrous bone fx, GCS <8, diffuse axonal injury.
Source: https://www.acep.org/uploadedFiles/ACEP/Membership/chapters/chapter_services/small_chapter_emails/BLUNT%20CEREBROVASCULAR%20INJURY.pdf