36. Lung

Question 1

Which radiographic technique should be used for TXR?

Answer 1

• Low mAs, high kVp

Question 2

What 3 characteristics of an alveolar pattern are described?

Answer 2

1) Air bronchogram
2) Lobar sign
3) Area of intense opacity without sharp margins (e.g. not a mass)

Question 3

What does a lobar sign describe?

Answer 3

Region of opaque lung bordering adjacent aerated lobe

Question 4

Detail 9 causes of an alveolar pattern (consider distribution and prevalence too..)

Answer 4

Question 5

What radiographic feature should be identified with atelectasis? What must be considered when interpreting atelectatic lung?

Answer 5

• MEDIASTINAL SHIFT
• > Can mask alveolar pathology. Cannot distinguish radiographically -> SAMPLING may be required

Question 6

In a bronchial pattern, where it the pathology?

Answer 6

• In the bronchial wall OR peribronchial space (actually a component of interstitium)

Question 7

List 5 additional radiographic features that can be seen in association with bronchial pathology

Answer 7

1) Lobar collapse
2) Rib fractures
3) Hyperlucent lung
4) Bronchiectasis
5) Bronchial mineralisationa

Question 8

List 5 causes of a bronchial pattern

Answer 8

Question 9

Which lung lobe most classically collapses in feline asthma?

Answer 9

Right middle

Question 10

What diseases have been associated with bronchiectasis? List radiographic features of bronchiectasis

Answer 10

DDx: Pneumonia, Eosionophilic bronchopneumopathy, inflammatory airway disease

Rx: Increased diameter, failure to taper in periphery, non-linear nature of wall, thickened wall (if bronchitis also)

Question 11

What 3 categories of disease have been associated with rib fractures in cats?

Answer 11

1) Respiratory (Most common)
2) Neoplasia (E.g. myeloma)
3) Metabolic (E.g. renal)

=> Osteopaenia associated with old age may play a role, as commonly older

Question 12

Which ribs are classicallly affected by spontaneous fracture in cats with respiratory disease?

Answer 12

9-13, mid-portion.

Question 13

What features of pulmonary hyperinflation may be recognised?

Answer 13

• Increased lucency
• Increased volume (increased cardiac / diaphragm distance)
• Tenting of diaphragm

Question 14

What bronchial structures may become mineralised

Answer 14

• Bronchial wall
• Bronchial plug
• Bronchial mucous glands

Question 15

In what instances is bronchial mineralisation typically seen?

Answer 15

• Cats with chronic bronchial disease -> bronchial pattern present
• Dogs with CUSHINGS -> No thickening of bronchi seen, and more diffuse

Question 16

What threshold value is suggested for pulmonary nodules on XR?

Answer 16

7-9mm

=> likely can vary depending on patient and technical factors

Question 17

What size can be used to distinguish mass from nodule?

Answer 17

20mm

Question 18

What features may be used to distinguish a pulmonary nodule from an end-on vessel?

Answer 18

Vessels:

• More opaque (as more summated)
• “tail” of vessel
• Proximity to bronchus
• Smaller diameter than expected of pulmonary nodule (visible due to increased opacity)

Question 19

Causes of interstitial nodules and masses

Answer 19

Question 20

What is the alternative name for heterotopic bone?

Answer 20

Pulmonary osseous metaplasia

Question 21

What methods can be used to confirm pulmonary location of nodule on XR?

Answer 21

• Fluoro -> coincedent movement of lung
• CT
• Check for superficial structures!
• Repeat TXR

Question 22

What radiographic features of adenocarcinoma and histiocytic sarcoma are described?

Answer 22

• Adenocarcinoma:

LEFT CAUDAL LOBE

• HS:

Tend to be larger

RIGHT MIDDLE, LEFT CRANIAL

Internal air bronchogram (>50%)

Question 23

What features of an acute traumatic bulla may distinguish it from a chronic bulla / congenital bulla?

Answer 23

• Irregular wall -> can have haemorrhage in wall
• Other features of trauma: contusion, pleural effusion, fractures etc.

Question 24

What is the difference between unstructured and structured interstitial patterns?

Answer 24

• Sturctured: Usually organised into discrete lesions
• Unstructured: NOT!

Question 25

What technical / patient factors may produce an unstructured interstitial pattern?

Answer 25

• Underexposure
• Underdevelopment
• Body habitus
• Atlectasis
• Expiratory

Question 26

List some key facts about unstructured intersititial patterns

Answer 26

• Increase in background opacity of lung
• When pathological often represent DYNAMIC pathologies e.g. oedema
• Must document in DV/VD as tendency for laterals to be opaque (atelectasis)

Question 27

Causes of unstructured intersitial pattern

Answer 27

Question 28

What does the airway vs non airway paradigm focus on?

Answer 28

• Sampling! If this dichotomy is used e.g. airway = bronchial / alveolar; nonairway = interstitial => Can guide sampling!

Airway = BAL

Non airway = FNA / biopsy

BE MINDFUL: Some patterns dont need sampling e.g. oedema. Watch for resolution and then sample if needed

Question 29

What radiographic features of cardiogenic oedema are described?

Answer 29

• Lung pattern: can be alveolar, interstitial OR BRONCHIAL (rarely) -> the latter category particularly in HCM or large dogs with DCM
• Caudodorsal or patchy most common, less commonly perihilar
• Tends to be less intense than pneumonic process
• Asymmetric vs symmetri distribution in in MVD: asymmetric vs central jet!

Question 30

What % of dogs demonstrate perihilar, diffuse or pathcy lung patterns with cardiogenic oedema?

Answer 30

Perihilar: 11.5%

Diffuse: 18%

Patchy: 70.5%

Question 31

Features of lung lobe torsion

Answer 31

• Large breeds: R middle
• Small breeds (Pugs): Left cranial
• Rx:

Vesicular pattern

Increased size

Pl effusion

Abnormal shape / position

Truncation / blunting / displacement of bronchus