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Fig. 4.72 Inspiration (a) and expiration (b) HRCT demonstrating lucency from air-trapping on the expiration CT (arrows in b) due to bronchiolitis obliterans
4 Abnormal Lung Patterns
a
b
Bronchial Wall Thickening
The following section starts with causes of bronchial wall thickening, findings, and an analog to demonstrate why the findings appear the way they do.
Bronchial Wall Thickening Causes
Bronchial wall thickening (bronchiectasis) involves a large differential diagnosis. Table 4.2 contains a complete list of causes.
Figure 4.73 is an example case from a patient with cystic fibrosis.
Bronchial Wall Thickening Model
Figures 4.74 and 4.75a are presented as a model to help explain bronchial wall thickening. This was published by Slotto and Folio and reprinted with permission [5].
Airway (Bronchial) Patterns |
97 |
Table 4.2 Causes of bronchiectasis |
|
|
|
Congenital |
Cystic fibrosis |
|
Kartagener’s syndrome |
|
Alpha-1-antitrypsin deficiency |
|
Bronchomalacia |
|
Yellow nail syndrome |
Severe inflammation |
Mycobacterium (i.e., tuberculosis) or NTM (Non-TB |
|
mycobacterium) |
|
MRSA |
|
Toxoplasmosis, rubella, CMV, herpes simplex, syphilis |
|
(TORCHES) |
|
Fungal infection |
Obstructive |
Foreign body aspiration |
|
Bronchial stricture |
|
Airway mass/tumor |
|
External compression |
Reprinted with permission from Slotto and Folio [5]
For organizational purposes, it is useful to divide bronchial wall thickening into the three broad categories shown on the left. Within each category, the most common disease entities are shown on the right
a |
b |
Fig. 4.73 Note the diffuse tram tracks and peribronchial cuffing representing the thickened bronchial walls on PA (a) and lateral (b). See the following analog for more detail of the findings
Figure 4.74 are gross photos of the experimental setup for plain computed radiography. The green sponge has contrast medium on half, and the blue has been soaked with water to better simulate tissue density.
Figure 4.75a shows the tram track in the experimental model, with plain film to the left and axial CT on the right. The plain film shows one straw in profile (left) and
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4 Abnormal Lung Patterns |
Fig. 4.74 |
Experimental |
setup for bronchial wall thickening model. Plain computed radiography (CR, a) and CT (b) were obtained of a sponge and an apple with straws piercing through to demonstrate air bronchograms (apple) and tram tracks (sponge) by analogy
a
b
Fig. 4.75a, b Tram track in experimental model. The plain CR image (a) is not as revealing as the CT (b)