Which imaging finding is most indicative of pulmonary edema?

Which imaging finding is most indicative of pulmonary edema?

• A. Interstitial thickening
• B. Batwing pattern
• C. Steeple sign
• D. Thumbprint sign

Answer: (B)

Pulmonary edema shows fluid accumulating in the lung interstitium and spaces around the central airways, creating a distinctive perihilar, symmetric haziness that often extends toward the lung bases. This gives the batwing (butterfly) pattern on a frontal chest radiograph, where the edematous opacities radiate from the hila outward in a V-shaped or wing-like distribution. This pattern is the strongest radiographic clue that edema is driving the changes, especially when paired with central vascular crowding and possible mild pleural effusions. Interpreting the other signs helps confirm why they’re less indicative of edema: steeple sign points to subglottic narrowing seen in croup, and the thumbprint sign reflects an enlarged epiglottis associated with epiglottitis. Those findings pertain to airway inflammation rather than interstitial or alveolar fluid overload.

Pulmonary edema shows fluid accumulating in the lung interstitium and spaces around the central airways, creating a distinctive perihilar, symmetric haziness that often extends toward the lung bases. This gives the batwing (butterfly) pattern on a frontal chest radiograph, where the edematous opacities radiate from the hila outward in a V-shaped or wing-like distribution. This pattern is the strongest radiographic clue that edema is driving the changes, especially when paired with central vascular crowding and possible mild pleural effusions.

Interpreting the other signs helps confirm why they’re less indicative of edema: steeple sign points to subglottic narrowing seen in croup, and the thumbprint sign reflects an enlarged epiglottis associated with epiglottitis. Those findings pertain to airway inflammation rather than interstitial or alveolar fluid overload.