Which radiographic finding is most consistent with pneumonia in a postoperative patient?

• A. Bilateral edema
• B. Normal chest X-ray
• C. Bibasilar infiltrates
• D. Pleural effusion

Answer: (C)

Pneumonia on chest X-ray shows air-space (alveolar) opacities from filling of the alveoli with inflammatory exudate. In a postoperative patient, the bases are a common site for infection to produce this pattern because gravity and shallow breathing tend to affect the lower lungs. Therefore, bibasilar infiltrates best fit pneumonia on radiographs in this context.

Edema usually produces a more diffuse, often perihilar or interstitial pattern rather than discrete base infiltrates. A normal chest X-ray would not be consistent with pneumonia. Pleural effusions can accompany infection but would show fluid at the costophrenic angles and may obscure or accompany base infiltrates rather than defining pneumonia itself.