Pediatric Chest Imaging

On this page

Normal Chest & Variants - Tiny Thorax Tour

  • Thymus: Prominent in infants; variable appearance.
    • Sail sign: triangular opacity, often right upper lobe (RUL).
    • Wave sign: undulating border from rib indentations.
    • Notch sign: inferiorly at cardiophrenic angle.
  • Cardiothoracic Ratio (CTR):
    • Neonate: < 0.6
    • Infant (<1yr): < 0.55
    • Child (>1yr): < 0.5
  • Ribs: More horizontal. Adequate inspiration: 8-9 posterior ribs visible.
  • Lungs: Appear more hyperlucent than adult lungs.
  • Trachea: Slight rightward deviation is common.
  • Common Variants: Azygos lobe/fissure.

⭐ The thymic sail sign and wave sign are classic normal findings in infants and young children, not to be mistaken for consolidation or mass.

Congenital Anomalies - Born This Way Lungs

  • Congenital Diaphragmatic Hernia (CDH): Herniation of abdominal contents into thorax; pulmonary hypoplasia.
    • Bochdalek (posterolateral, L>R), Morgagni (anteromedial).
  • Congenital Pulmonary Airway Malformation (CPAM): Hamartomatous lung lesion; communicates with airway. Types 0-4.
  • Pulmonary Sequestration: Non-functioning lung; systemic arterial supply; no normal bronchial communication.
    • Intralobar (ILS): No own pleura; drains to pulmonary veins.
    • Extralobar (ELS): Own pleura; drains to systemic veins.
  • Bronchogenic Cyst: Foregut duplication; mediastinal/intrapulmonary; no airway communication.
  • Congenital Lobar Emphysema (CLE): Lobar overinflation; check-valve mechanism.

⭐ Bochdalek hernia: most common CDH (~85%), posterolateral, usually left; scaphoid abdomen.

Infections & Inflammations - Little Lung Invaders

Key differences in common pediatric pneumonias:

FeatureViral PneumoniaBacterial Pneumonia
PatternDiffuse interstitial, peribronchial cuffingLobar/segmental consolidation, air bronchograms
LateralityOften bilateralOften unilateral
Pleural EffusionLess commonMore common
Common PathogensRSV, Influenza, AdenovirusS. pneumoniae, H. influenzae
> ⭐ Round pneumonia is characteristic in children <**8** years due to underdeveloped pores of Kohn and canals of Lambert.
  • Miliary TB: Diffuse, fine 1-2 mm nodular opacities (millet seed pattern) throughout both lungs. Pediatric chest X-ray: Miliary pattern (TB)

Neonatal Distress - First Breath Battles

  • Respiratory Distress Syndrome (RDS): Prematurity, surfactant deficiency.
    • CXR: Fine reticular/ground-glass opacities, air bronchograms, low lung volumes.
  • Transient Tachypnea of Newborn (TTN): Delayed resorption of fetal lung fluid.
    • CXR: Perihilar streaking, fluid in fissures, pleural effusions. Resolves 24-72 hrs.
  • Meconium Aspiration Syndrome (MAS): Post-term, fetal distress.
    • CXR: Coarse, patchy opacities, hyperinflation, risk of pneumothorax.
  • Neonatal Pneumonia: Group B Strep common.
    • CXR: Diffuse alveolar opacities, consolidation; can mimic RDS.
  • Pulmonary Interstitial Emphysema (PIE): Barotrauma (ventilated infants).
    • CXR: Linear or cystic lucencies.

⭐ Respiratory Distress Syndrome (RDS) classically presents with fine reticular or ground-glass opacities and prominent air bronchograms on chest X-ray, primarily due to surfactant deficiency in premature infants.

CXR: Neonatal RDS ground glass opacities

Airway Issues & Tumors - Windpipe Woes & Growths

  • Croup (Laryngotracheobronchitis): Viral; subglottic edema. X-ray: Steeple sign (AP).

  • Epiglottitis: Bacterial; supraglottic. X-ray: Thumb sign (lateral). ⚠️ Emergency. Thumb sign on lateral neck X-ray

  • Foreign Body Aspiration (FBA): Peak 1-3 yrs. Expiratory X-ray: air trapping, mediastinal shift.

    ⭐ The right main bronchus is the most common location for inhaled foreign body aspiration in children.

  • Tracheomalacia: Dynamic tracheal collapse (expiration). Fluoroscopy/CT.

  • Pediatric Mediastinal Masses:

    CompartmentCommon Masses
    Anterior📌 "4 T's": Thymus, Teratoma, Thyroid, Terrible Lymphoma
    MiddleLymphadenopathy (lymphoma, TB), Cysts (Bronchogenic, Duplication)
    PosteriorNeurogenic (Neuroblastoma - common), Cysts (Duplication)
    Pediatric posterior mediastinal masses by decade

High‑Yield Points - ⚡ Biggest Takeaways

  • Thymic "sail sign" on CXR is normal in infants, not a mass.
  • RDS shows diffuse ground-glass opacities, air bronchograms, and low lung volumes.
  • TTN presents with perihilar streaking, interlobar fluid, resolving in 24-72 hrs.
  • MAS features coarse, patchy infiltrates, hyperinflation, and risk of pneumothorax.
  • CDH (Bochdalek) has bowel in chest, scaphoid abdomen, usually left-sided.
  • Round pneumonia is common in children <8 years, appearing as a posterior round opacity.
  • Foreign body aspiration causes unilateral air trapping (expiratory/decubitus views).

Practice Questions: Pediatric Chest Imaging

Test your understanding with these related questions

The 'steeple sign' on X-ray neck (as shown in the image) is characteristically seen in which of the following diseases?

1 of 5

Flashcards: Pediatric Chest Imaging

1/10

What is the imaging of choice for diagnosing appendicitis in children?_____

TAP TO REVEAL ANSWER

What is the imaging of choice for diagnosing appendicitis in children?_____

USG

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial