For a patient with acute head trauma from a motor‑vehicle crash (on anticoagulation, GCS ≤ 8, focal neurological deficits or repeated vomiting), should the initial head CT be performed with or without contrast?

Initial Head CT for Acute Trauma Should Be Performed WITHOUT Contrast

For a patient with acute head trauma from a motor vehicle crash who is on anticoagulation, has GCS ≤ 8, focal neurological deficits, or repeated vomiting, the initial head CT must be performed without contrast. 1, 2

Why Noncontrast CT Is Mandatory

• Contrast administration obscures acute hemorrhage, which is the primary life-threatening complication you need to detect immediately in head trauma. 2
• Noncontrast CT rapidly identifies all neurosurgical emergencies: epidural hematoma, subdural hematoma, subarachnoid hemorrhage, intraparenchymal hemorrhage, cerebral edema, mass effect, herniation syndromes, and skull fractures. 3, 4
• CT with contrast provides no additional diagnostic value in acute head trauma and may actually mask early hemorrhagic complications. 2

Evidence-Based Rationale

Guideline Recommendations

• The American College of Radiology (ACR) Appropriateness Criteria explicitly recommends noncontrast head CT as the initial imaging study for moderate to severe head trauma (GCS ≤ 12). 1, 2
• The American College of Emergency Physicians gives a Level A recommendation for noncontrast head CT in patients with coagulopathy (including anticoagulation therapy), regardless of trauma severity. 2
• For patients with GCS ≤ 8 (severe head trauma), noncontrast CT is the gold standard because it detects neurosurgical lesions with near 100% sensitivity for hemorrhage. 1, 4

Your Patient's High-Risk Features

• Anticoagulation: This alone mandates CT imaging even with minimal trauma, as these patients have substantially elevated risk of intracranial hemorrhage. 2
• GCS ≤ 8: Severe head trauma has a 66% or higher prevalence of intracranial lesions requiring neurosurgical intervention. 1
• Focal neurological deficits: This is a high-risk criterion in all validated clinical decision rules (Canadian CT Head Rule, New Orleans Criteria), with an odds ratio of 7 for intracranial lesions. 3
• Repeated vomiting: Listed as an indication for CT in both major clinical decision rules. 1, 3

When Contrast Would Be Appropriate

Contrast-enhanced studies are ONLY indicated if you suspect vascular injury, in which case you would order CT angiography (CTA), not standard contrast-enhanced CT. 1, 2

Indications for CTA (not routine contrast CT):

• Suspected arterial dissection or occlusion 2
• Signs of large vessel injury from penetrating trauma 1
• Clinical suspicion of traumatic arteriovenous fistula 1

For your patient's presentation, there is no indication for CTA unless specific vascular injury is suspected based on mechanism or clinical findings. 1

Critical Pitfall to Avoid

Do not order CT with contrast for routine head trauma evaluation. This is a common error that:

• Delays diagnosis by requiring contrast administration time 2
• Obscures hemorrhage detection 2
• Provides no benefit over noncontrast CT for detecting neurosurgical lesions 1
• May complicate interpretation if delayed hemorrhage develops 4

Imaging Protocol Details

• Obtain multiplanar reformatted images to increase diagnostic accuracy. 1
• Include bone algorithm reconstructions to evaluate skull fractures. 2
• Ensure images cover the entire calvarium and skull base. 1