Pediatric Radiology
Core Concepts
Pediatric radiology emphasizes radiation protection, age-specific imaging protocols, and recognition of congenital and developmental anomalies. You must know the common pediatric emergencies: pyloric stenosis (ultrasound showing thickened pyloric muscle), intussusception (target sign on ultrasound, barium enema for reduction), malrotation with volvulus (upper GI series showing corkscrew sign), and necrotizing enterocolitis (pneumatosis intestinalis). Also, understand the differences in pediatric chest imaging: thymus (sail sign), round pneumonia, and foreign body aspiration (decubitus views).
Common Traps
A common trap is choosing the wrong modality: ultrasound is preferred for pyloric stenosis and intussusception, while upper GI series is needed for malrotation. Another trap is misinterpreting normal variants as pathology, such as the thymic sail sign or prominent periventricular halos in neonates. Also, beware of radiation dose: ALARA is paramount; use ultrasound and MRI when possible.
Worked Example
A 6-week-old boy with projectile vomiting. Ultrasound shows a pyloric muscle thickness >3 mm and channel length >15 mm, diagnostic of pyloric stenosis. The next step is surgical pyloromyotomy. Rule of thumb: projectile vomiting in a 3-6 week old = pyloric stenosis until proven otherwise.
Key Points
- Pyloric stenosis: ultrasound is diagnostic (muscle thickness >3 mm).
- Intussusception: ultrasound shows target sign; barium enema is therapeutic.
- Malrotation: upper GI series shows corkscrew sign.
- Necrotizing enterocolitis: pneumatosis intestinalis on X-ray.
- ALARA: minimize radiation in children.