In a patient with a history of cranial trauma and left‑eye swelling, should a head CT be performed with or without contrast?

CT Head Without Contrast for Cranial Trauma with Left Eye Swelling

For a patient with cranial trauma and left eye swelling, perform CT without IV contrast—specifically either CT orbits or CT maxillofacial depending on the extent of suspected injury. Contrast is not indicated and provides no additional diagnostic value in acute traumatic settings.

Imaging Recommendation

The 2025 ACR Appropriateness Criteria explicitly state that CT maxillofacial without IV contrast and CT orbits without IV contrast are the appropriate initial imaging studies for posttraumatic vision loss and orbital trauma 1. The guidelines are unequivocal that there is no relevant literature supporting the use of contrast-enhanced CT in initial imaging of posttraumatic vision loss 1.

Which Non-Contrast CT to Order:

• CT Orbits without contrast: Use when trauma is directly localized to the orbital region (direct blunt or penetrating injury to the eye)
• CT Maxillofacial without contrast: Use when additional facial injuries are suspected beyond the orbit, as it images from the frontal sinus through the mandible 1

Given your patient has "cranial trauma" (not just isolated eye trauma) with left eye swelling, CT maxillofacial without contrast is likely the better choice as it provides comprehensive evaluation of both the orbit and surrounding facial structures that may be injured 1.

Why No Contrast?

Multiple sources confirm contrast adds no value and may be harmful in acute trauma:

• The ACR guidelines explicitly state no literature supports contrast use in posttraumatic orbital imaging 1
• Contrast can lower sensitivity for detecting hemorrhage, which is critical in trauma 2
• Research from 1984 and 2015 demonstrated no incremental diagnostic information from contrast in acute head injury 3, 4
• Non-contrast CT rapidly detects all critical traumatic findings: fractures, hemorrhage, globe injuries, retrobulbar hematoma, and optic nerve injury 1

What the CT Will Detect

Non-contrast CT effectively identifies vision-threatening injuries requiring urgent intervention 1:

• Orbital fractures: Including trapdoor fractures and orbital compartment syndrome
• Globe injuries: Rupture, intraocular hemorrhage, lens dislocation, open globe
• Retrobulbar pathology: Hematoma (retrobulbar and subperiosteal), emphysema
• Optic nerve injury: Direct and indirect traumatic optic neuropathy
• Extraocular muscle injury or herniation
• Foreign bodies: Radio-opaque intraorbital foreign bodies and bone fragments

Additional Considerations

Add CT head without contrast as a complementary study if you suspect concomitant traumatic brain injury or intracranial hemorrhage 1. This is common—68% of patients with maxillofacial injuries have associated head injury 5.

Critical Pitfall to Avoid:

Do not delay imaging to obtain contrast. The ACR guidelines emphasize that multidetector CT without contrast can be acquired quickly, allows multiplanar reformations, and can image multiple body parts concurrently in polytrauma 1. Speed is essential as some findings (severe proptosis with posterior globe tenting, orbital compartment syndrome) require emergent decompression to preserve vision 1.

Clinical Diagnosis Remains Paramount:

Note that imaging demonstration of retrobulbar hemorrhage is not sensitive for subsequent development of orbital compartment syndrome—this diagnosis must be made on clinical findings 1. Examine for afferent pupillary defect, proptosis, and vision changes regardless of imaging findings.