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
