What is the role of Transcranial Ultrasound (TCUS) in the management of craniosynostosis?

Role of Transcranial Ultrasound (TCUS) in Craniosynostosis Management

Transcranial ultrasound (TCUS) should be used as the first-line imaging modality for suspected craniosynostosis in infants, as it provides sufficient diagnostic information with no radiation exposure, while CT or MRI should be reserved for surgical planning. 1

Diagnostic Approach for Craniosynostosis

Initial Evaluation

• The diagnosis of craniosynostosis is primarily clinical, based on abnormal skull shape and palpation of fused sutures 1
• Key clinical findings to assess:
  • Abnormal head shape (scaphocephaly, plagiocephaly, trigonocephaly, brachycephaly)
  • Ridging along suture lines
  • Fontanelle abnormalities
  • Signs of increased intracranial pressure (bulging fontanelle, papilledema)

Role of TCUS in Diagnosis

• TCUS is the preferred initial imaging study for suspected craniosynostosis in infants 1
• Advantages of TCUS:
  • No radiation exposure (particularly important in infants)
  • Can adequately visualize cranial sutures and fontanelles
  • Non-invasive and does not require sedation
  • Cost-effective compared to CT/MRI
  • Can be performed at bedside

When to Use TCUS

• For suspected anomalies of cranial sutures and anterior fontanelle 1
• For initial screening of infants with abnormal head shapes
• For monitoring suture status in high-risk infants (e.g., those with family history)
• For follow-up after surgical intervention

Advanced Imaging Considerations

When to Escalate to CT/MRI

• CT or MRI should not be used as routine examinations for craniosynostosis 1
• Advanced imaging is indicated only when:
  1. Surgical intervention is being planned 1
  2. TCUS findings are inconclusive
  3. Complex or syndromic craniosynostosis is suspected
  4. Signs of increased intracranial pressure are present 2
  5. Evaluation of intracranial complications is needed

Specific Imaging Recommendations

• For surgical planning: CT examination is indicated 1
• For suspected intracranial hypertension: MRI with black bone sequence is recommended 1
• For syndromic cases: Consider more comprehensive imaging to evaluate associated anomalies 1

Special Considerations

Syndromic vs. Non-syndromic Craniosynostosis

• Non-syndromic cases (isolated suture fusion) are more common (~70% of cases) 3
• Syndromic cases require more extensive evaluation:
  • Loeys-Dietz Syndrome: Craniosynostosis may be present with characteristic facial features and bifid uvula 1
  • Crouzon Syndrome: May present with progressive postnatal craniosynostosis requiring vigilant monitoring 2

Monitoring for Complications

• Regular monitoring for increased intracranial pressure is essential, especially in:
  • Multiple-suture involvement
  • Progressive postnatal craniosynostosis
  • Syndromic cases
• Warning signs requiring immediate attention:
  • Papilledema
  • Anterior fontanelle bulging
  • "Thumbprinting" on skull radiographs 2

Clinical Pathway for Management

1. Clinical diagnosis based on head shape and physical examination
2. TCUS as first-line imaging for confirmation of diagnosis 1
3. Referral to multidisciplinary craniofacial team if craniosynostosis is confirmed
4. Advanced imaging (CT/MRI) only for surgical planning or suspected complications 1
5. Early surgical intervention for severe cases to prevent neurological complications 3
6. Regular follow-up to monitor for increased intracranial pressure and developmental issues 4

Pitfalls and Caveats

• Do not confuse deformational plagiocephaly (positional flattening) with true craniosynostosis
• TCUS has limitations in older infants as the acoustic window diminishes with age and ossification
• Isolated finding of abnormal skull shape without clinical symptoms does not necessarily mandate MRI 1
• Delayed diagnosis can lead to increased risk of intracranial hypertension and neurodevelopmental impairment 4
• Regular monitoring is crucial for patients with progressive postnatal craniosynostosis, as they may develop increased intracranial pressure despite initially normal head shape 2