Pediatric Emergency Imaging

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Pediatric Imaging Principles - Little Bodies, Special Rules

  • ALARA: "As Low As Reasonably Achievable" radiation. Children are radiosensitive.
    • 📌 Image Gently campaign.
  • Modality Hierarchy:
    • USG first (abdomen, pelvis): No radiation.
    • X-ray: Bones, initial chest.
    • CT: Trauma, complex cases; use low-dose protocols.
    • MRI: Soft tissue, neuro; often needs sedation.
  • Sedation: Key for motion-free MRI/CT. Consider age, procedure (e.g., chloral hydrate).
  • Contrast: Weight-based. Iodinated (CT): 1-2 mL/kg. Gadolinium (MRI): lower NSF risk.

⭐ USG is the workhorse in pediatric emergency imaging: safe, accessible, no ionizing radiation.

Pediatric CT Radiation Doses

Pediatric Trauma - Spotting Hidden Harm

  • Non-Accidental Injury (NAI):
    • Skeletal survey: Suspected NAI, unexplained fractures (#s), esp. < 2 yrs.
    • Key findings:
      • Metaphyseal "corner"/bucket-handle #s.
      • Posterior rib #s (squeezing).
      • Skull #s: multiple, bilateral, depressed, crossing sutures, different ages.
      • Spinous process, sternal, scapular #s.
      • Multiple #s in varied healing stages.

    ⭐ Metaphyseal "corner" or "bucket-handle" fractures are highly specific for NAI. Classic metaphyseal corner fractures NAI

  • Common Accidental Fractures:
    • Torus (buckle) #: Cortex bulges.
    • Greenstick #: Incomplete #, cortex bent.
  • Salter-Harris Classification (Epiphyseal Plate Injuries): 📌 SALTR
    • Type I (Slipped): Through physis.
    • Type II (Above): Physis + Metaphysis (Most common).
    • Type III (Lower): Physis + Epiphysis.
    • Type IV (Through): Metaphysis + Physis + Epiphysis.
    • Type V (Ruined): Crush injury to physis (Poor prognosis). Salter-Harris Fracture Types I-V Diagram
  • Head Trauma:
    • Initial imaging: CT for moderate/severe trauma.
    • PECARN rule helps decide CT use in low-risk children to reduce radiation.

Acute Abdomen Imaging - Gut Instincts Visualized

Key pediatric abdominal emergencies and their imaging hallmarks:

  • Intussusception
    • USG: "Target sign" (bowel-within-bowel), "pseudo-kidney sign". Best initial test. Pediatric Intussusception Ultrasound Target Sign
    • Air/Contrast Enema: Diagnostic & therapeutic; "meniscus sign" or "coiled spring" appearance.
  • Appendicitis
    • USG: Non-compressible, blind-ended tubular structure >6mm diameter; "target sign" (transverse); periappendiceal fluid/fat stranding.
    • CT: If USG equivocal or suspicion of perforation/abscess.
  • Malrotation with Volvulus
    • UGI Series (Gold Standard): "Corkscrew sign" of duodenum/jejunum. Abnormal duodenojejunal (DJ) flexure position.
    • USG: "Whirlpool sign" (SMV rotates around SMA). Inverted SMA/SMV relationship.
  • Hypertrophic Pyloric Stenosis (HPS)
    • USG: Pyloric muscle thickness >3-4mm, channel length >14-16mm. "Olive sign" (palpable), "cervix sign" (USG). Pyloric Stenosis in Infants
  • Necrotizing Enterocolitis (NEC)
    • Abdominal X-ray (Supine & Decubitus): Pneumatosis intestinalis (pathognomonic), portal venous gas, pneumoperitoneum (Rigler's sign, football sign).

⭐ Target sign (doughnut sign) on USG is pathognomonic for intussusception.

Imaging Acute RLQ Pain in Children:

Chest & Neuro Emergencies - Breathless & Brainy

  • Respiratory Emergencies:
    • Pneumonia: X-ray patterns (lobar, interstitial, round) aid diagnosis.
    • Foreign Body Aspiration (FBA):
      • Inspiratory X-ray: Unilateral hyperinflation, atelectasis.
      • Expiratory/Decubitus X-ray: Air trapping, mediastinal shift to normal side.
    • Croup (Laryngotracheobronchitis):
      • X-ray (AP neck): Steeple sign (subglottic narrowing).
    • Epiglottitis: ⚠️ Medical emergency!
      • X-ray (lateral neck): Thumb sign (swollen epiglottis). Caution: Clinical diagnosis prioritized; imaging if airway stable.
      • Thumb sign on lateral neck X-ray in epiglottitis
  • Neurological Emergencies:
    • Non-traumatic Seizures: CT/MRI if focal, prolonged, new-onset (>6mo, afebrile), abnormal exam, or post-traumatic.
    • Hydrocephalus:
      • Infants: USG (ventricular size, IVH screen).
      • Older: CT/MRI (detailed anatomy, cause).
    • Hypoxic-Ischemic Injury (HIE): MRI shows patterns (basal ganglia/thalamus-term; watershed; periventricular leukomalacia-preterm).

⭐ Steeple sign (Croup, AP) for subglottic narrowing vs. Thumb sign (Epiglottitis, Lateral) for swollen epiglottis.

High‑Yield Points - ⚡ Biggest Takeaways

  • NAI: Suspect with multiple fractures (varied healing), posterior rib, or metaphyseal corner fractures.
  • Intussusception: Target sign (USG); air/contrast enema is diagnostic & therapeutic.
  • Pyloric Stenosis: USG: thickened pylorus (>3mm), elongated canal (>14mm).
  • Malrotation/Volvulus: Upper GI series (corkscrew) is gold standard; USG: whirlpool sign.
  • Appendicitis: Graded compression USG (appendix >6mm, non-compressible) is key.
  • NEC: X-ray: pneumatosis intestinalis, portal venous gas.
  • Epiglottitis: Thumbprint sign (X-ray); Croup: Steeple sign (X-ray).

Practice Questions: Pediatric Emergency Imaging

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The Salter Harris classification is used for classifying which type of injuries?

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Flashcards: Pediatric Emergency Imaging

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What is the best modality to identify cocaine packets in a body packer?_____

CT imaging

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