The term "tree in bud appearance" is a radiological finding seen on computed tomography (CT)

Tree in Bud Appearance

→ Distal airways (more common)

→ Distal pulmonary vasculature

→ Typically the centrilobular nodules are 2-4 mm in diameter and peripheral, within 5 mm of the pleural surface.

→ Connection to opacified or thickened branching structures extends proximally

The term “tree in bud appearance” is a radiological finding seen on computed tomography (CT) scans of the chest. It describes a pattern of small nodules or branching linear opacities that resemble the branches of a tree, with the nodules located along the bronchial tree or pulmonary vasculature. Here are some key points about the tree in bud appearance:

  1. Distal airways: The tree in bud appearance is most commonly observed in the distal airways, particularly the small bronchioles. It indicates inflammation or infection within these airways, leading to the appearance of nodules or branching opacities.
  2. Distal pulmonary vasculature: In addition to the airways, the tree in bud appearance can also involve the distal pulmonary vasculature. This can occur when the infection or inflammation extends into the small blood vessels of the lungs.
  3. Size and location of nodules: The centrilobular nodules associated with the tree in bud appearance are typically small, measuring around 2-4 mm in diameter. They are often located in the periphery of the lungs, within 5 mm of the pleural surface.
  4. Proximal extension: The nodules or branching opacities seen in the tree in bud appearance are connected to opacified or thickened branching structures that extend proximally. This suggests a relationship between the inflammatory or infectious process and the affected airways or blood vessels.

The tree in bud appearance is a nonspecific finding and can be associated with various conditions, including infections such as bronchiolitis, bronchiectasis, or pneumonia. It can also be seen in certain non-infectious conditions such as allergic bronchopulmonary aspergillosis (ABPA) or endobronchial spread of malignancies.

It is important to correlate the radiological findings with clinical symptoms, medical history, and additional diagnostic tests to determine the underlying cause and appropriate management. A thorough evaluation by a healthcare professional, such as a pulmonologist or radiologist, is essential for accurate diagnosis and management.