What do you look for on a neck computed tomography (CT) scan in a patient with suspected strangulation?

Neck CT Imaging in Strangulation Patients

In a patient with suspected strangulation, perform CT angiography (CTA) of the neck with IV contrast as the primary imaging modality to evaluate for vascular injuries (particularly carotid and vertebral artery dissections), followed by careful assessment of laryngohyoid fractures, soft tissue injuries, and airway compromise. 1, 2

Primary Imaging Approach

CTA Neck with IV Contrast is First-Line

• CTA neck should be the initial advanced imaging study in alert, stable strangulation patients, as it provides comprehensive evaluation of both vascular and non-vascular injuries with sensitivity of 90-100% and specificity of 98.6-100% for vascular injuries. 1, 2
• CTA simultaneously identifies extravascular soft-tissue and aerodigestive injuries with 100% sensitivity and 93.5-97.5% specificity. 1, 3
• Vascular injuries, particularly cervical artery dissections, are the most clinically significant findings requiring specific treatment, though they occur in only 2-4% of strangulation cases. 4, 5

When to Image

• Obtain CTA in patients with concerning findings beyond isolated neck pain, specifically: Glasgow Coma Scale (GCS) score <15, dysphagia, loss of consciousness, or neurologic deficits. 4
• Alert patients (GCS ≥13) with only neck pain and no other concerning symptoms have extremely low rates of clinically important injuries (0.6%), suggesting selective imaging may be appropriate. 4

Critical Findings to Identify on CT

Vascular Injuries (Highest Priority)

• Carotid or vertebral artery dissection: Look for vessel irregularity, wall thickening/mural hematoma, pseudoaneurysm, intimal flap, or luminal narrowing. 2
• These injuries require antiplatelet therapy (typically aspirin) even without neurologic deficits. 4
• Use thin-slice imaging (1mm) to avoid missing subtle vascular injuries. 6

Laryngohyoid Fractures

• Hyoid bone fractures are the most common skeletal injury in strangulation and are well-visualized on CT. 7, 8
• Thyroid cartilage fractures are equally important and detected with equivalent accuracy to autopsy on CT. 7, 8
• A "gas bubble sign" (gas within or adjacent to fractured laryngeal structures) may facilitate detection of these fractures. 8

Soft Tissue Injuries

• Subcutaneous emphysema indicates airway or pharyngeal injury and is readily visible on CT. 1, 3
• Soft tissue swelling and hematomas in neck musculature, though CT has limited sensitivity compared to MRI for detecting hemorrhages. 7, 8
• Airway compromise: Assess for laryngeal edema, hematoma causing airway narrowing, or tracheal injury. 1, 6

Additional Findings

• Pneumomediastinum or pneumothorax from associated airway injury. 1
• Cervical spine fractures, particularly if mechanism involved hanging or significant force. 1

Technical Considerations

CT Protocol Specifics

• Use thin-slice (1mm) acquisition to maximize detection of small fractures and subtle vascular injuries. 6
• Arterial phase timing is essential for optimal vascular evaluation. 1, 2
• Obtain multiplanar reconstructions (sagittal and coronal) to better visualize laryngohyoid structures and cervical spine. 1

Why CTA Over Non-Contrast CT

• Non-contrast CT alone misses the most clinically significant injuries (vascular dissections) that require specific treatment. 2, 4
• The added value of contrast for detecting life-threatening vascular injuries far outweighs the minimal risk of contrast administration in stable patients. 1, 2

Role of Alternative Imaging

MRI: Reserved for Specific Situations

• MRI of the neck is superior to CT for detecting soft tissue hemorrhages in neck musculature, with nearly equivalent accuracy to autopsy. 9, 8
• Consider MRI when: (1) CT is negative but high clinical suspicion persists, (2) evaluating for spinal cord injury, or (3) documenting soft tissue injuries for forensic purposes. 1, 9
• MRI should be performed "as soon as possible" after strangulation if cerebral damage is suspected. 9
• Do not obtain MRI before excluding metallic foreign bodies with radiographs or CT. 6

Plain Radiographs: Limited Utility

• Initial neck radiographs may demonstrate radio-opaque foreign bodies, gross soft-tissue swelling, or airway compromise, but have poor sensitivity for clinically significant injuries. 1, 6
• Radiographs are generally followed by CTA in the trauma setting. 1

Ultrasound: Not Recommended

• Ultrasound has limited utility due to overlying soft tissue injury, inability to evaluate deep structures, and operator dependence. 6, 2, 3

Clinical Context and Risk Stratification

High-Risk Features Requiring Imaging

• GCS score <15 (altered mental status). 4
• Dysphagia or odynophagia. 4
• Loss of consciousness during or after strangulation. 4, 5
• Neurologic deficits. 4
• Visible neck bruising/petechiae with neck tenderness (though these alone have low predictive value for vascular injury at 4.1% and 2.1% respectively). 5

Lower-Risk Presentation

• Alert patients (GCS 15) with isolated neck pain and no dysphagia have injury rates of only 1.7%, with clinically important injuries in 0.6%. 4
• However, history and physical examination alone cannot reliably predict vascular injury, as neck pain (51%), loss of consciousness (47%), and headache (22%) were common but had weak predictive value (4.1%, 4.5%, and 3.2% respectively for vascular injury). 5

Common Pitfalls to Avoid

• Do not rely on clinical examination alone to exclude vascular injury, as symptoms are non-specific and physical findings have poor predictive value. 5
• Do not obtain non-contrast CT when vascular injury is a concern—CTA is required to evaluate for dissection. 2, 4
• Do not assume CT detects all soft tissue hemorrhages—CT has limited sensitivity for muscle hemorrhages compared to MRI or autopsy. 7, 8
• Do not skip imaging in patients with altered mental status or dysphagia, even if external neck findings are minimal, as these predict higher injury rates. 4
• Do not forget to assess for end-organ injury (brain) when cervical vascular injury is identified, as stroke may occur. 1