Aspiration Pneumonitis
Aspiration Pneumonitis

This is an image at the level of the middle lobe bronchus. It shows ill-defined nodular opacities, several mm in diameter, predominating in the posterior right lung. The nodules are centrilobular in location, as most peripheral nodules are centered about 5 mm from the pleural surface (red arrow). Some of the opacities have a branching appearance (blue arrow). This is termed "tree in bud," and may be seen with pulmonary edema of various causes, hemorrhage, bronchopneumonia, hypersensitivity pneumonitis, follicular bronchiolitis, and other forms of small-airways disease. "Tree in bud" has been reported with aspiration.