Tree-in-bud pattern
Updates to Article Attributes
The treeTree-in-bud sign describes the CT appearance of multiple areas of centrilobular nodules with a linear branching pattern. Although initially described in patients with endobronchial tuberculosis, it is now recognised in a large number of conditions.
Pathology
Pathogenesis
The tree-in-bud sign occurs as a result of a number of processes, although often they co-exist in the same condition:
- bronchioles filled with pus or inflammatory exudate
-
bronchiolitis
- thickening: thickening of bronchiolar walls and bronchovascular bundle- e.g. cytomegalovirus pneumonitis, obliterative bronchiolitis
-
bronchiectasis with mucus plugging
- e.g. cystic fibrosis
-
tumour emboli to centrilobular arteries (or carcinomatous endarteritis) 3
- e.g. breast cancer, stomach cancer
- bronchovascular interstitial infiltration
- e.g. lymphoma, leukaemia 4-5
Aetiology
The tree-in-bud appearance represents endobronchial spread of infection. Causes include:
- infective bronchiolitis
- congenital
- connective tissue disorders
- bronchial
- neoplastic
Radiographic features
Tree-in-bud sign is not visible on plain film 2 and is best seen on HRCT. Typically they are composed of centrilobular nodules (which are usually 2-4mm in diameter and peripheral, within 5 mm of pleural surface) connected by opacified or thickened branching structures extending proximally (representing the dilated and opacified bronchioles) 1-3.
-<p>The <strong>tree-in-bud sign</strong> describes the CT appearance of multiple areas of <a href="/articles/centrilobular-lung-nodules-1">centrilobular nodules</a> with a linear branching pattern. Although initially described in patients with <a href="/articles/pulmonary-manifestations-of-tuberculosis">endobronchial tuberculosis</a>, it is now recognised in a large number of conditions.</p><h4>Pathology</h4><h5>Pathogenesis</h5><p>The tree-in-bud sign occurs as a result of a number of processes, although often they co-exist in the same condition:</p><ul>- +<p><strong>Tree-in-bud sign</strong> describes the CT appearance of multiple areas of <a href="/articles/centrilobular-lung-nodules-1">centrilobular nodules</a> with a linear branching pattern. Although initially described in patients with <a href="/articles/pulmonary-manifestations-of-tuberculosis">endobronchial tuberculosis</a>, it is now recognised in a large number of conditions.</p><h4>Pathology</h4><h5>Pathogenesis</h5><p>The tree-in-bud sign occurs as a result of a number of processes, although often they co-exist in the same condition:</p><ul>
-<a href="/articles/bronchiolitis">bronchiolitis</a> - thickening of bronchiolar walls and bronchovascular bundle<ul><li>e.g. cytomegalovirus pneumonitis, <a href="/articles/obliterative-bronchiolitis">obliterative bronchiolitis</a>- +<a href="/articles/bronchiolitis">bronchiolitis</a>: thickening of bronchiolar walls and bronchovascular bundle<ul><li>e.g. cytomegalovirus pneumonitis, <a href="/articles/obliterative-bronchiolitis">obliterative bronchiolitis</a>
-</ul><h5>Aetiology</h5><p>The tree-in-bud appearance represents endobronchial spread of infection. Causes include</p><ul>- +</ul><h5>Aetiology</h5><p>The tree-in-bud appearance represents endobronchial spread of infection. Causes include:</p><ul>
Image 1 Photo ( update )
Image 6 CT (lung window) ( update )
Image 7 CT (lung window) ( update )
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