Pulmonary Radiography Flashcards
describe the lung lobes
- named for the branching of the principle bronchi into the lobar bronchi
-dogs and cats: 4 lobes on the right, 2 lobes on the left - left principle bronchus:
-2 lobar bronchi: cranial and caudal
-cranial lobar bronchus immediately divides into cranial and caudal subsegments of the cranial lobe - right principle bronchus:
-3 lobar bronchi: cranial, middle, caudal
-accessory originates from the right caudal lobar bronchus
describe the pulmonary parenchyma
3 components contribute to what is seen (CT is gold standard for pulm eval)
Air within the small airways and vessels
Blood vessels
Airway walls
describe radiographic eval of lungs
- always take 3 projections of thorax
-due to lesion conspicuity
-both laterals (RL and LL)
-VD or DV - pulmonary opacity:
-normal, reduced, or increased
-increased: in most diseases, where we see pulmonary patterns
-normal: should see vessels spreading to periphery; if don’t see vessels well = something abnormal
describe reduced pulmonary opacity
- also called pulmonary (hyper) lucency
- lungs appear darker/more black
- increased gas opacity and decreased soft tissue opacity in the lungs
-small vessels or no vessels
describe 3 causes of diffuse reduced pulmonary opacity
- hypovolemia:
-small vessels, small heart, small CdVC
-hypovolemic shock, hypoadrenocorticism - increased thoracic volume:
-hyperinflation/air trapping: feline asthma - artifact: over exposure
describe 3 ddx for focal reduced pulmonary opacity
- (multi)focal lucency (ies)
-bulla, bleb, pneumatocele, cavitated mass - regional oligemia: pulmonary thromboembolism
3, bronchial dilation: bronchiectasis
GENERALLY describe pulmonary lung patterns
- increased pulmonary opacity: lungs appear wider
-occurs in most of the diseases - causes:
-soft tissue opaque material within the air spaces: blood, pus, water, cells
-thickening of the pulmonary interstitium/connective tissue
-nodules/masses
-bronchial wall thickening
-enlarged pulmonary vessels
what are the 4 types of lung patterns?
- alveolar
- interstitial:
-unstructured
-structured (miliary, nodular, masses) - bronchial
- +/- vascular:
-enlarged pulmonary arteries, veins, or both
-small pulmonary arteries, veins, or both
first question is: can I see the vessels? if so, probs normal
many patterns are actually mixed, search for the most predominant and go from there
describe how unstructured interstitial and alveolar patterns are related
a continuum! with a similar list of differential diagnoses
try to classify differentials by location:
1. cranioventral: bronchopneumonia
2. caudodorsal: pulmonary edema
3. ventral: aspiration pneumonia
4. multifocal: contusions, fungal pneumonia, metastasis
5. diffuse: lymphoma, ARDS
pattern reflects SEVERITY: progresses FROM unstructured interstitial TO alveolar, like fog is less bad closer to the ground and gets worse as move up (more opaque = worse)
use your recheck exam to determine which way you are moving on the continuum
what are common differentials for alveolar and unstructured interstitial
- atelectasis
- aspiration pneumonia
- bronchopneumonia
- pneumonitis
- pulmonary edema
-cardiogenic
-non-cardiogenic - neoplasia: lymphoma (unstructured interstitial)
describe the alveolar lung pattern
VERY important!! if you miss and don’t do anything, patient will probs die overnight
4 main features: don’t need to have ALL 4 to = alveolar pattern
1. uniform grey: absent visualization of vessels (thick fog in the woods)
- border effacement with adjacent soft tissue/fluid opaque structures
- air broncograms:
-air filled bronchus surrounded by soft tissue opaque lung - lobar sign:
-abnormal lung border contrasted with normal lung border; the disease is respecting the lobar border!
-will not see if disease affecting all lung lobes
describe the unstructured interstitial lung pattern
radiographic findings:
- increased soft tissue opacity that PARTIALLY obscures pulmonary vascular margins
- hazy
- never mild!! always moderate or severe
-mild = too many ddx so is artifactual essentially, only label of moderate to severe
rank the amount of connective tissue in the lungs of different species
dogs and cats < horses < farm animals
can see vessels better with less CT, horses more opaque compared to dogs and cats, ruminants more opaque, alligator snapping turtle hella opaque
describe fake outs (3) and ddx (4) for unstructured interstitial patterns
fake outs:
1. underexposure
- expiratory radiographs: smaller lung lobe volume causes vessels to be closer together and look more opaque
- large body habitus: overweight
if real: very nonspecific unless know location
1. pneumonia
2. pneumonitis
3. fibrosis: WHWT
4. lymphoma
describe the structured interstitial lung pattern
- technical name for nodules and masses
-most commonly soft tissue opacity, but could be mineral opacity or gas opaque or mixed - based on difference in size
-miliary: approx 1mm; very small nodules/pinpoint lesions
-nodule: <3cm; can be subtle; look over diaphragm and vertebrae
-mass: >3cm
give 2 common ddx for miliary structured interstitial
fungal pneumonia, metastatic neoplasia
give 3 common ddx for nodules and 5 fake outs
- metastatic neoplasia
-mammary carcinoma, hemangiosarc, thyroid carcinoma) - fungal pneumonia (blastomycosis, often with TB lymphadenopathy)
- benign pulmonary osteomas (miner opaque)
-could be abscess and granuloma formation, but this is less common in small animals
fake outs:
1. end-on vessels: same or smaller size and more opaque than adjacent longitudinal (side-on) vessel, less numerous in periphery
2. cutaneous nodules
3. nipples
4. ectoparasites
5. osteomas
give 5 common ddx for masses
- primary neoplasia: more common if only see one mass (metastasis is more likely multiple masses)
-broncheoalveolar carcinoma: usually caudal lungs
-histiocytic sarcoma: usually mass superimposed over cardiac silhouette
-lymphoma - inflammatory: usually in young dogs (young dog = less likely neoplasia initially, but are so severe could become neoplastic over time)
-pulmonary eosinophilic granulomatosis
-lymphatoid granulomatosis - abscess: migrating foreign bodies most commonly
- granuloma
- lung lobe torsion: not a true structured interstitial pattern but may look like a mass
describe structured interstitial pattern of pulmonary osseous metaplasia
- heterotopic bone, pulmonary osteomas, osteomata, pneumoliths
-common in collies and shelties - small (<5mm), may be numerous, often more ventrally
- MINERAL OPAQUE
describe cutaneous nodules
- skin tags, nipples, papillomas, ticks
-distinct, sharply marginated opacity superimposed on lungs
-surrounded by air (half of the surface)
-but the margin in contact with the skin is ill-defined
-a pulmonary nodule is well defined all the way around - careful exam of patient is critical
- use positive contract (Barium) or a metallic marker and then re-radiograph
describe the bronchial pattern
- due to chronic inflammation;
-many bronchi are normally visible in a centrally (hilar) position so always look in periphery = more variation and easier to tell if thickened walls - thickened walls are abnormal
- RINGS and LINES: donut and tram lines
-rings: end-on small airways
-lines: airways moving from central to peripheral position - usually generalized disease
- cats: may have concurrent mucous plugs (small nodules)
describe the common differentials for the bronchial pattern
- bronchial wall mineralization (dogs) is NOT a bronchial pattern, just happens
- chronic bronchitis: infectious, allergic, irritant
- asthma: cats
- eosinophilic bronchopneumopathy: dogs
- heartworm disease: in combo with other findings
describe the bronchial pattern with bronchiectasis
- abnormal and PERMANENT bronchial dilation secondary to chronic airway disease
- rad findings:
-increased bronchial lumen diameter: failure to taper peripherally
-thickened bronchial wall
what are the ways to describe distribution of pulmonary changes?
- cranial or caudal, dorsal or ventral
- focal (lobar), multifocal, or diffuse
- hilar, mid-zone, peripheral
give the common differentials for variable location lung patterns, also where cardiogenic edema, pulmonary pneumonia, and aspiration and bronchopneumonia usually life
1.variable locations:
-hemorrhage/trauma or diffuse coagulopathy
-PTE (pulmonary thromboembolism: peripheral to diffuse
-ARDS: usually diffuse
(acute respiratory distress syndrome)
- cardiogenic edema: usually caudodorsal, perihilar
- caudodorsal: pulmonary edema usually affects here
- cranioventral: aspiration pneumonia and bronchopneumonia usually live here
describe consolidation
-increased opacity with NORMAL TO INCREASED lung volume
-lungs are filled with something other than air (blood, pus, water, cells)
-will result in an unstructured interstitial to alveolar pattern
describe atelectasis/collapse
- lungs are collapsed
- increased opacity with DECREASED lung volume
-usually see shift of cardiac silhouette to fill the gap (ipsilateral mediastinal shift) - possible underlying disease
- will result in an unstructured interstitial to alveolar pattern
describe bullas/blebs
gas filled structures with a thin soft tissue opaque wall!
diff from masses (thick, ill-defined walls)
describe lung lobe torsion
- uncommon
- important ddx for lobar consolidation
- +/- vesicular pattern: pathognomonic of lung lobe torsion (gas trapped and forms bubbles inside torsed lobe initially, rabsorbed later on)
-abnormal lobar bronchial path: easier to see on CT; may see interruption of lung lobe lumen (CT is gold standard to eval for lung lobe torsion) - concurrent pleural effusion is very common
- caudal lobes rarely torsion
-pugs: left cranial LL
-afghan hounds: right middle LL
-rare in cats
describe the vascular pattern
any changes along pulmonary lobar vessels:
-enlarged
-small
-tortuous
describe ddx for enlarged arteries and veins
- fluid overload
- left sided cardiac failure: esp cats
describe ddx for enlarged arteries with normal veins
- pulmonary hypertension
-due to heartworm disease or important pulmonary fibrosis
describe didx for small arteries and veins
- hypovolemia
- addison’s disease
describe ddx for enlarged veins with normal arteries
left-sided heart failure
describe equine pulmonary disease
- same pulmonary patterns as SA
-just need craniodorsal, cranioventral, caudodorsal, and caudoventral views - associate predominant pulmonary pattern and location for ddx
-ddx may differ from SA though - cavitated structured interstitial pattern: pulmonary abscesses
- caudodorsal peripheral unstructured interstitial: exercise-induced pulmonary hemorrhage
-diff from SA! - caudodorsal alveolar, esp with dorsal tracheal displacement: pulmonary edema
