Imaging: Lower Airway Flashcards
what is a pulmonary pattern
a radiographic sign; does NOT correspond to a specific disease
helps generate DDX
interstitial pattern appearance
MILD increase in pulmonary opacity
- “frosted glass”
- can see underlying structures but has haze over it
- poorly defined vessels
cause of interstitial pattern
increased fluid/cells in the pulmonary connective tissue (not alveoli or bronchial walls)
ddx for interstitial pattern
- normal - old dogs, obesity, artifact
- pneumonitis - viral, parasitic, metabolic, toxic
- disease in transition (early or resolving)
- neoplasia - lymphosarcoma, diffuse metastasis
- pulmonary fibrosis
vascular pattern appearance
MILD increase in pulmonary opacity
- prominent, well-defined vessels
- increased # of vessels
cause of vascular pattern
overcirculation
ddx for vascular pattern
- L to R shunts
- fluid overload
- AV fistula
bronchial pattern appearance
Increased bronchial wall visualization
- “donuts and tram tracks”
cause of bronchial pattern
increased fluid/cells within or around bronchial walls
ddx for bronchial pattern
- bronchitis - allergic, viral, parasitic
- early pulmonary edema
- neoplasia
- bronchial mineralization (mineral opacity)
alveolar pattern appearance
MARKED increased pulmonary opacity
- silhouette sign
- air bronchogram
- lobar sign
- diffuse or patchy
silhouette sign
loss of differentiation between cardiac silhouette, pulmonary vessels, and diaphragm due to increase ST opacity in surrounding areas
air bronchogram
“tree in the fog” - air filled bronchus surrounded by fluid (ST opaque)
lobar sign
abrupt/obvious demarcation between lung lobes
often affects single lobes
cause of alveolar pattern
fluid filled alveoli (transudate, exudate, blood)
or
collapsed pulmonary tissue
ddx for alveolar pattern
- pneumonia - aspiration (lobar) or embolic (diffuse/patchy)
- edema - cardiogenic vs non-cardiogenic
- hemorrhage
- atelectasis
how to ID cardiogenic pulmonary edema
L sided heart failure
concurrent cardiomegaly and enlarged pulmonary vessels w/ alveolar pattern
dogs: perihilar and caudo-dorsal alveolar pattern
cats: patchy or diffuse/ventral alveolar pattern
how to ID non-cardiogenic pulmonary edema
high pressure (fluid overload) or high permeability (ARDS, neurologic)
NO concurrent cardiomegaly and normal pulmonary veins
how to ID hemorrhagic alveolar pattern
often asymmetric
nodular pattern appearance
focal, rounded ST opacities
can be single, multiple, or large
DDX for nodular pattern
- neoplasia
- inflammatory - granulomas
- pulmonary abscess
primary neoplasia appearance
solitary, large mass
metastatic neoplasia appearance
widespread, small nodules
benign osteomas
many small (<5 mm) mineral opacities in older dogs
