2. centrilobu-lar bronchial dilatation and filling by
mucus, pus, or fluid resembles a budding tree
Usually somewhat nodular in appearance, the tree-in-bud pattern is
generally most pro-nounced in the lung periphery and associated with
abnormalities of the larger airways
3. The tree-in-bud pattern is indicative of a spectrum of
endo- and peribronchiolar disorders with dilatation;
bronchiolar wall thickening;
peribronchiolar inflammation;
bronchiolar luminal impaction with mucus, pus, fluid, or, as more
recently, tumor emboli.
7. Viral Infection
CMV in immunocompromised pts
an cause bronchiolitis with centrilobular nodules and thickening of the bronchovascular
bundles that produce the tree-in-bud pattern.
Progress>> GGO’s
+- poorly defined nodules with the CT halo sign.
9. Kartagener Syndrome
dyskinetic cilia syndromes
CT findings
bilateral bronchiectasis with a basal predominance.
Airway damage can extend to the smaller airways,
causing bronchiolectasis,air trapping,
centrilobular opacities producing the tree-in-bud pattern
10. Idiopathic Disorders
Obliterative Bronchiolitis
also known as constrictive bronchiolitis, is an irreversible fibrosis
of small airway walls that narrows or obliterates the lumen, leading
to chronic airway obstruction
Causes include infection (viral, bacterial, mycoplasma),
inhalation of toxic fumes,
drug treatment (penicillamine or gold),
collagen vascular disease (rheumatoid arthritis,
especially after the therapies mentioned),
chronic lung transplant rejection,
and bone marrow transplantation with chronic graft-versus-host disease.
12. Aspiration or Inhalation of Foreign Substances
chronic inflammatory reaction
Predisposing factors : structural abnormalities
of the pharynx, esophageal disorders (achalasia, Zenker
diverticulum, hiatal hernia and
reflux, esophageal carcinoma), neurologic defects, and
chronic illness
In acute cases, extensive exudative bronchiolar disease
may develop and result in centrilobular nodules and the
tree-in-bud pattern in a distribution characteristic of
aspirated material.
13. Immunologic Disorders
Allergic bronchopulmonary aspergillosis -> IgE and IgG antibodies->inflammatory reaction
damage to the bronchial wall, central bronchiectasis, and the formation of mucous plugs coniains mucus and
plugs
finger-in-glove sign of large airway impaction, Involvement of the small airways causes the tree-in-
bud pattern
14. Connective Tissue Disorders
Rheumatoid Arthritis
CT Findings :
Interstitial pneumonia and fibrosis,
Pleural effusion or pleural thickening,
Necrobiotic nodules,
Organizing pneumonia,
Bronchiectasis,
Obliterative bronchiolitis.
More extensive lymphocytic
infiltrations may be associated with lymphoid interstitial
pneumonia (LIP), with groundglass
opacities, consolidation, septal thickening mimicking the
lymphangitic spread of carcinoma,
and cystic air spaces. This condition progresses to fibrosis
in about one third of patients
15. Sjögren Syndrome
Clinical triad of keratoconjunctivitis sicca, xerostomia, and recurrent swelling of the parotid gland.
follicular bronchiolitis, interstitial pneumonia, organized pneumonia, tracheobronchial gland
inflammation, and pleuritis with or without effusion
Peripheral Pulmonary Vascular Disease
The lung is a frequent site of tumor embolism, most commonly from choriocarcinoma and
primary malignancies of the liver, breast, kidney, stomach, and prostate.
Filling of the centrilobular arteries with tumor cells or a rare widespread fibrocellular intimal hyperplasia of
small pulmonary arteries (carcinomatous endarteritis) may produce the tree-in-bud pattern.
the tree-in-bud pattern is indicative of a spectrum of endo- and peribronchiolar disorders with dilatation; bronchiolar
wall thickening; peribronchiolar inflammation; and bronchiolar luminal impaction with mucus, pus, fluid, or, as described more recently,
tumor emboli.
First described in cases of endobronchial spread of Mycobacteriu tuberculosis, the tree-in-bud pattern is now recognized as a CT manifestation of such
various entities as infection
In Bacterial diseases-most common postprimary tb, The tree-in-bud pattern suggests active and contagious disease, especially when associated with adjacent cavitary disease within the lungs
In Bacterial diseases-most common postprimary tb, may reflect reinfection with
new organismsThe tree-in-bud pattern suggests active and contagious disease, especially when associated with adjacent cavitary disease within the lungs.
Tuberculosis.A and B, Peripheral treein bud opacities (circle, A) combine to produce more peripheral centrilobular nodules
The most common CT findings are centrilobular nodules and branching linear and nodular opacities
Invasive airway aspergillosis causing bronchiolitis occurs most commonly in neutropenic patients and individuals who are immunologically suppressed with AIDS.
Invasive airway aspergillosis causing bronchiolitis occurs most commonly in neutropenic patients and individuals who are immunologically suppressed with AIDS. Fungal hyphae are often found in the airway lumen.pneumonia and tracheobronchitis.
Invasive airway aspergillosis should be suggested when the tree-in-bud pattern + consolidation+ halo of ground-glass opacity
autosomal-recessive hereditary disorder involving the exocrine glands, resulting in the production of abnormal secretions by the salivary and sweat glands, pancreas,
large bowel, deferent ducts, and tracheobronchial tree. A block in the transport of chloride into the bronchial lumen and the excessive resorption of sodium leads to the production of thick and dry mucus, resulting in decreased clearance of mucus and eventually mucous plugging in small and large airways and subsequent bacterial infection.
cystic fibrosis showing widespread cylindrical bronchiectasis and mucus plugging of the large and smaller airways (the latter is seen as a “tree-in-bud” pattern in the right middle lobe). The apparent wall thickening of some of the bronchiectatic airways is considerable (arrows), and in part reflects endoluminal secretions.
Obliterative bronchiolitis. CT image shows extensive right lower lobe area of peripheral treein-bud opacities (arrows). Nodular component of opacities is smaller but well defined.
It represents a transmural infiltration of lymphocytes and plasma cells, with mucus and neutrophils filling the lumen of affected bronchioles.
Most affected individuals are nonsmokers and have chronic sinusitis.
In addition to thick-walled bronchioles filled with mucus and producing the tree-in-bud pattern, there may be nodules, bronchiectasis, large cystic opacities accompanied by dilated proximal bronchi, and mosaic perfusion or air trapping.
Chronic aspiration. Tree-in-bud opacities (arrows) in right lower lobe. Note hiatal hernia. Nodular component of changes may later coalesce and create ground-glass appearance.
hyperimmune response to airway colonization with Aspergillus species commonly seen in patients with asthma and cystic fibrosis.
Peripheral tree-in-bud opacities (arrows, A) can often be accompanied by more proximal airway abnormalities, such as mucous plugging B
A lymphoid interstitial infiltrate in the walls of the small airways (follicular bronchiolitis) may cause small centrilobular nodules and the tree-in-bud pattern
As with rheumatoid arthritis, lymphoid interstitial infiltrate in the wallsof the small airways may produce the tree-in-bud pattern
