Pediatric Radiology
Paediatric Radiology tests age-appropriate protocols, radiation reduction, congenital disease and non-accidental injury.
Dose and technique
Children have higher radiosensitivity and longer lifetime risk. Use as low as reasonably achievable with weight-based kVp and mAs, iterative reconstruction, gonadal shielding where appropriate, and ultrasound or MRI instead of CT when possible. The Image Gently campaign summarises these principles.
Common emergencies
Intussusception: target sign on ultrasound; air enema reduction is first line if there is no perforation or peritonitis. Pyloric stenosis: pylorus over 3 mm thick and over 14 mm long on ultrasound. Malrotation: volvulus with a swirl sign; upper gastrointestinal contrast study shows an abnormal duodenojejunal junction. Necrotising enterocolitis: pneumatosis intestinalis in a premature infant. Developmental dysplasia of the hip: ultrasound before 6 months, radiograph after.
Non-accidental injury
Fractures of different ages, posterior rib fractures, metaphyseal corner fractures and unexplained injuries should prompt a skeletal survey and child protection referral.
Worked example
A 4-month-old with bilious vomiting has an ultrasound showing a swirl sign and a contrast study with a corkscrew duodenum. This is midgut volvulus from malrotation; the next step is urgent surgical review, not a barium meal follow-through.
Traps
Using adult CT parameters in a child; mistaking a normal thymus for a mass; calling a round pneumonia a tumour; delaying surgery for volvulus to complete imaging; forgetting a skeletal survey in suspected abuse.