When is a skull x-ray (radiograph) indicated in infants?

Indications for Skull X-rays in Infants

Skull x-rays should not be routinely used in infants and should be limited to cases where there is visible evidence of head injury or suspicion of non-accidental trauma. 1, 2

Clinical Decision-Making Algorithm

Skull X-rays ARE indicated in infants when:

• Suspected non-accidental trauma (child abuse) 1, 2, 3
• Visible signs of head injury (e.g., scalp hematoma) with unclear mechanism 1, 2, 3
• Clinical examination is equivocal and imaging is needed to rule out craniosynostosis 1
• Suspected depressed skull fracture or penetrating injury that requires confirmation 2, 4

Skull X-rays are NOT indicated in infants when:

• Routine screening for intracranial injury (ICI) 1, 2
• Diagnosis of mild traumatic brain injury (mTBI) 1
• Neurological signs/symptoms are present (CT is preferred) 1, 2
• Routine evaluation after minor head trauma without visible injury 3, 5

Rationale and Evidence

Limited Diagnostic Value

• Skull radiographs have only 63% sensitivity for diagnosing skull fractures in children 1
• They cannot detect intracranial injuries such as hemorrhage, midline shift, or edema 1
• Severe intracranial injury can occur in the absence of skull fracture 4

Preferred Imaging Alternatives

• CT is the gold standard for detecting both skull fractures and intracranial injuries when imaging is clinically indicated 1, 2
• MRI may provide additional diagnostic information in about 25% of children compared to CT, but is not recommended for routine acute evaluation 1, 2

Radiation Exposure Considerations

• Reducing unnecessary skull x-rays decreases radiation exposure to infants 3, 5
• One study demonstrated a 47.5% reduction in skull radiographs after policy change without missing significant injuries 3

Special Considerations for Infants

Anatomical Vulnerability

• Infants have thinner skull bones, open fontanelles, larger head-to-body ratio, and weaker neck muscles 2
• These factors make them more susceptible to head injury and require careful assessment

Clinical Assessment Challenges

• Infants are difficult to assess clinically, which historically led to overreliance on radiological examination 3
• Clinical neurological abnormalities are more reliable predictors of intracranial injury than skull x-rays 4

Common Pitfalls to Avoid

1. Over-reliance on normal skull x-rays: A normal skull x-ray does not exclude intracranial injury 5, 4
2. Missed fractures: Emergency department staff may miss up to 23% of fractures on skull radiographs 4
3. Failure to consider non-accidental trauma: Always consider this possibility when mechanism of injury is unclear or inconsistent with injury pattern 2, 3
4. Unnecessary radiation: Routine skull x-rays after minor head trauma expose infants to unnecessary radiation without clinical benefit 5

By following these evidence-based guidelines, clinicians can make appropriate decisions about when to use skull x-rays in infants, balancing the need for diagnostic information with concerns about radiation exposure and the limitations of this imaging modality.