Tree-in-bud is a pattern seen on chest CT where small airways and their associated tiny lung sacs appear as branching, budded shapes — typically a sign of infection or inflammation in the small airways.
The pattern itself is an imaging finding; the underlying cause may produce cough (sometimes with sputum), fever, breathlessness, or chest discomfort.
Imaging shows the pattern's distribution, which helps narrow the cause — bacterial infection, tuberculosis, atypical infections, or chronic small airway disease.
High-resolution CT of the chest is the test that shows the pattern best.
Treatment targets the underlying cause — antibiotics for bacterial infection, anti-tuberculous therapy when TB is confirmed, and specialist care for atypical infections or chronic small airway disease.
This entry explains the word. If it appeared on your report, the next step is getting that report interpreted for your case.