Is CT (Computed Tomography) scan contraindicated in children?

CT Scans in Children: Risks and Appropriate Use

CT scans are not contraindicated in children, but should be used judiciously with careful consideration of radiation risks versus diagnostic benefits, following the ALARA (as low as reasonably achievable) principle.

Radiation Risks in Pediatric CT

Children are particularly vulnerable to radiation exposure from CT scans due to:

• Greater radiation sensitivity of actively dividing cells 1
• Longer life span allowing more time for radiation-induced tumor development 1, 2
• Increased lifetime cancer risk compared to adults 3, 4

Recent studies have provided evidence of small but real cancer risks:

• A Dutch nationwide study found that cumulative brain dose from CT scans (average 38.5 mGy) was significantly associated with increased risk for brain tumors (ERR/100 mGy: 0.86) 5
• Three large-scale studies from the UK, Australia, and USA have demonstrated a small but real risk of malignancy associated with CT scans in early life 4

Appropriate Use Guidelines

When CT is Appropriate:

1. Trauma situations:

   • First-line test for acute moderate and severe traumatic brain injury 1
   • For suspected vascular trauma 1
   • When evaluating for skull fractures or bone lesions 1

2. When MRI is contraindicated:

   • Patients with cochlear implants, cardiac pacemakers, or other MRI contraindications 1
   • When MRI will have significantly limited diagnostic yield due to spinal hardware 1

3. Emergency situations:

   • Unstable patients requiring rapid imaging 1
   • When acute intracranial hemorrhage is suspected 1

Risk Reduction Strategies:

1. Clinical observation before CT:

   • For mild traumatic brain injury (GCS scores 14-15), clinical observation before deciding on CT is an effective strategy to reduce unnecessary radiation exposure 1
   • Every additional hour of ED observation is associated with decreased CT rates without delaying diagnosis of significant injuries 1

2. Use of clinical decision rules:

   • The Pediatric Emergency Care Applied Research Network (PECARN) rule helps identify children at very low risk for clinically important TBI who can safely avoid CT scans 1

3. Technical considerations:

   • Weight and size-based CT parameters should be adjusted for pediatric patients 1
   • Use of adaptive statistical iterative reconstruction tools can reduce radiation dose by approximately 20% 1
   • Following the Image Gently® campaign guidelines to minimize radiation exposure 1

Alternative Imaging Modalities

When clinically appropriate, consider these alternatives:

1. MRI:

   • Preferred for neuroimaging due to lack of ionizing radiation 1
   • Superior detection of soft tissue abnormalities 1
   • Ideal for evaluation of children with positive neurologic findings 1

2. Ultrasonography:

   • Non-radiating imaging modality that has increased in pediatric use 1
   • May replace CT for many conditions, though it is operator-dependent 1

Common Pitfalls to Avoid

1. Routine whole-body CT in pediatric trauma:

   • Should not be performed in pediatric trauma patients 1
   • Not recommended for screening asymptomatic children with high-energy mechanism 1

2. Inadequate dose reduction:

   • Nearly 25% of EDs do not have reduced-dose radiation protocols for CT imaging 1
   • Ensure pediatric-specific protocols are in place 1

3. Unnecessary repeat imaging:

   • Repeat assessment of mild TBI with negative initial CT results is not recommended 1

Conclusion

While CT scans deliver higher radiation doses than most imaging modalities, they remain a powerful diagnostic tool when used appropriately. The clinical benefits of a medically necessary CT scan almost always outweigh the small long-term risk of malignancy 4. Implementation of CT guidelines in pediatric trauma centers has been shown to significantly decrease CT use without negatively impacting clinical outcomes 6.