Consolidation: watch the air bronchograms move

Answer d. Movement of air bronchograms with breathing shows air flowing through open airways into consolidated lung. This dynamic sign strongly supports pneumonia. In resorptive atelectasis the airway is blocked, so the bronchograms stay still. Effusion and pneumothorax do not show air bronchograms.

Answer a. Static air bronchograms mean air is not moving through the airway. This is common in resorptive atelectasis. Some pneumonias show static bronchograms too, so their presence does not exclude infection. Use the history, examination and the rest of the scan.

Answer d. Airless lung carries the beam like solid organ tissue, so it looks like liver, a pattern called hepatisation. Its deep edge, where it meets aerated lung, is often ragged (the shred sign). A black space above the diaphragm is an effusion. A-lines with sliding are normal aerated lung. Vertical bright lines are B-lines.

Answer c. Fluid-filled airways look like black branching tubes. Colour Doppler separates them from vessels, which fill with colour. Fluid bronchograms suggest an obstructed airway, as in post-obstructive pneumonia. Air bronchograms are bright, not black.

Answer c. The linear probe gives high resolution near the surface, so it shows small subpleural consolidations and the pleural line in detail. Use the curvilinear probe for deeper or larger areas and the lung bases.