Which radiographic finding is most characteristic of meconium aspiration syndrome?

• A. Ground-glass pattern with diffuse atelectasis
• B. Diffuse reticular markings without hyperinflation
• C. Normal radiographic appearance
• D. Coarse irregular densities with hyperinflation and air trapping

Answer: (D)

Meconium aspiration syndrome disrupts airways with obstruction and inflammation, leading to air trapping and patchy lung opacities on imaging. The chest radiograph most characteristic of MAS shows coarse irregular densities distributed throughout the lungs plus hyperinflation and evidence of air trapping from the obstructed airways. This pattern reflects both the chemical pneumonitis from meconium and the airway obstruction that creates trapped air and overinflation.

Ground-glass patterns with diffuse atelectasis are more typical of surfactant deficiency/respiratory distress syndrome, not MAS. Diffuse reticular markings without hyperinflation don’t fit the MAS pattern, and a normal radiographic appearance would be unlikely in MAS.