What is the recommended initial imaging modality for a suspected C-spine (cervical spine) injury?

Initial Imaging for Suspected Cervical Spine Injury

CT of the cervical spine without IV contrast is the recommended initial imaging modality for suspected cervical spine injury when imaging is indicated by NEXUS or Canadian C-Spine Rule (CCR) clinical criteria. 1

Clinical Decision Rules for Imaging

Before proceeding with any imaging, patients should be evaluated using validated clinical decision rules:

• NEXUS Criteria: No imaging needed if ALL criteria are met:

  • No midline cervical tenderness
  • No focal neurologic deficit
  • Normal alertness
  • No intoxication
  • No painful distracting injury

• Canadian C-Spine Rule (CCR): No imaging needed if:

  • No high-risk factors (age ≥65, dangerous mechanism, paresthesias)
  • Has low-risk factors that allow range of motion assessment
  • Able to rotate neck 45° left and right

Both criteria have high sensitivity (81.2-99.6% for NEXUS, 100% for CCR) but low specificity (12.9-45.8% for NEXUS, 0.6-42.5% for CCR). 1

Imaging Algorithm for Suspected C-Spine Injury

1. Initial Imaging: CT Cervical Spine Without IV Contrast

   • Gold standard for identifying cervical spine fractures 1
   • Significantly more sensitive than radiographs (97% vs 33% detection rate) 1, 2
   • Outperforms radiographs in high-, moderate-, and low-risk stratifications 1
   • Recent studies report sensitivity of 88.6% (specificity 99%) 3

2. Secondary Imaging: MRI Cervical Spine Without IV Contrast when:

   • Neurologic deficits are present
   • Suspected spinal cord or nerve root injury
   • Suspected ligamentous injury
   • Obtunded patients with negative CT
   • CT findings are equivocal

3. Supplemental Lateral Radiograph may be considered:

   • To evaluate the C2 region if there is concern about horizontal plane fractures that might be missed on CT 2
   • As a problem-solving tool in case of motion on cervical spine CT 1

Strengths and Limitations of Each Modality

CT Cervical Spine

• Strengths:
  • Excellent for identifying fractures (97% detection rate) 4
  • Fast acquisition time
  • Widely available in trauma centers
• Limitations:
  • Limited for soft tissue injuries (0% detection of spinal cord injuries, 25% of ligamentous injuries) 4
  • Radiation exposure
  • May miss horizontal plane fractures at C2 2

MRI Cervical Spine

• Strengths:
  • Superior for soft tissue evaluation (100% detection of spinal cord injuries, 100% of ligamentous injuries) 4
  • No radiation exposure
  • Can identify injuries missed on CT in 5-24% of cases 1
• Limitations:
  • Limited availability in emergency settings
  • Longer acquisition time
  • May require sedation in uncooperative patients
  • Less sensitive for fracture detection (55% detection rate) 4

Radiographs

• Limitations:
  • Poor sensitivity (identifies only about 33% of fractures visible on CT) 1
  • Largely supplanted by CT for trauma evaluation
  • Requires multiple views (anteroposterior, lateral, open-mouth odontoid)
  • Often inadequate visualization of cervicothoracic junction

Special Considerations

• Obtunded Patients: MRI is recommended following negative CT to evaluate for ligamentous injury 1
• Pediatric Patients: Different approach may be needed - radiographs may be appropriate initial imaging in low-risk scenarios to minimize radiation exposure 1
• Concomitant Facial Trauma: Higher risk of cervical spine injury (7-11.3% of facial fracture patients have concomitant cervical spine injury) 1

Common Pitfalls to Avoid

1. Relying solely on radiographs - they miss approximately 67% of fractures visible on CT 1
2. Failing to obtain MRI when neurologic symptoms are present despite negative CT
3. Not evaluating the cervicothoracic junction - ensure complete visualization
4. Overreliance on flexion-extension views - often inadequate and rarely demonstrate instability not seen on conventional imaging 1
5. Missing C2 fractures on CT - consider supplemental lateral radiograph if there is high clinical suspicion 2

The most recent evidence supports CT as the primary imaging modality for suspected cervical spine injury, with MRI as a complementary examination when soft tissue or neurological injury is suspected or when CT findings are equivocal.