Lung

Front 1

What affects the appearance of normal lung?

Back 1

Species and Breed
Age
Body condition - obese, thin
degree of ventilation
radiographic technique
body wall/rib structures

Front 2

Lung inflation changes

Back 2

Front 3

Chest Conformation

Back 3

deeper chest, obese, barrel chest

normal lungs: white tree branches on dark background (pulmonary vessels in everything else filled with gas)

Hint 3

Front 4

Lung Patterns

Back 4

Interstitial - unstructured
Alveolar
Bronchial
(Vascular)

Front 5

(Unstructured) Interstitial Pattern

Back 5

See pulmonary vessels, but margins indistinct (blurry)
increased lung opacity
-perihilar, diffuse

(CHF)

Hint 5

Front 6

Alveolar Pattern

Back 6

Can not see lung vessels at area of pattern
+/- air bronchograms present
+/- lobar sign present
increased lung opacity

caused by completely non-aerated portion of lung
if no air in lung, the pulmonary vessels will silhouete with lungs and become non-visible

Hint 6

caused by lung disease (no gas in alveoli because they're filled with fluid or cells) (assume this first)

caused by atalectasis (no gas in alveoli because they're collapsed) - determine incidental cause of lung volume loss vs pathologic cause of volume loss or lobar airway obstruction

Front 7

Air Bronchograms

Back 7

Air bronchogram is when gas remains in bronchus within a region of lung with an alveolar pattern
"black tree branches on white background"
hallmark of alveolar pattern
-absence of seeing vessel outer margins

Hint 7

will disappear if bronchus becomes filled with fluid/cells or becomes collapsed

Front 8

Lobar Sign

Back 8

Sharp delineartion at the margin of an alveolar pattern and some adjacent aerated lung lobe
useful to draw attention to aleolar pattern
indicated process is focal to affected lobe, not diffuse

Hint 8

Front 9

Atalectasis

Back 9

changes in lung volume - decreased size
(vs. diseased lobes will be normal or increased)
on DV/VD view
1. mediastinal shift towards the collapsed lobe
2. direct visualization of lobe margins with decreased lobe sign (commonly right middle lobe)

Hint 9

Front 10

Bronchial Pattern

Back 10

accentuation (thickening) of airway walls (bronchial walls)
caused by fluid or cells gathering around or within airway wall
often used as indicator of disease particular to the airway
- seen end on (doughnuts) or seen side on (parallel lines/train tracks)
diffuse exaggeration of airway markings
concurrent interstitial pattern often also present (broncho-interstital pattern)

Hint 10

Front 11

Lung Nodules

Back 11

sphere of soft tissue (4-5mm) - faint soft tissue opaque - smallest visible nodule
round structure in lung <4-5mm: either end on vessel or nodule made of mineral (benign osseous metaplasia/osteoma or mineralized granuloma)

Hint 11

Front 12

End on vessels

Back 12

often misdiagnosed by students as nodules
represent a length of vessel
should be same length as overlying vessel
should be more opaque than overlying vessel

Front 13

Benign Pulmonary Osteomas

Back 13

mostly 1-2mm
as opaque or more opaque than ribs

Front 14

Miliary Pattern

Back 14

lung apperance suggests many very small nodules difficult to seperate (like grains of sand) - summation of many small nodules
e.g. lymphoma

Front 15

Bronchopneumonia

Back 15

one of the most common lung diseases
bacterial infection enters through the airways
typically settles to the gravity dependent potion (ventral)
variable signs of inflammation, variable cough, commonly caused by aspiration of GI contents from vomiting or regurgitation (aspiration pneumonia)
may occur secondary to viral insult or immune compromise
-primary rule out for ventrally distributed alveolar pattern -lag behind clinical symptoms

Hint 15

Front 16

Cardiogenic Pulmonary Edema

Back 16

fluid displaced into the lung interstitium and alveolar spaces from left congestive heart failure
typically see radiographic left heart enlargement and pulmonary venous congestion
dogs: perihilar and caudodorsal lung regions
interstitial to alveolar with severity
cats: distribute anywhere (ventrally, diffusely, multifocal, can have prominent bronchial component)

Hint 16

Front 17

Feline Cardiogenic Edema

Back 17

commonly not appearing to predominate perihilar region, seen throughout thorax
often broncho-interstitial distribution
often accompanied by pleural and pericardial effusion

uncommonly localized to perihilar region

Hint 17

Front 18

Non-cardiogenic Pulmonary Edema

Back 18

numerous causes (seizures, head trauma, choking, strangulation, electrocution, systemic inflammation, pancreatitis, CKD)
large component of acute lung injury
-worst form is ARDS (acute respiratory distress syndrome)

ultimately results in leaky lung vessels, fluid often more proteinaceous than cardiogenic edema, responds more slowly to diuretic therapy
distributed in caudodorsal lungs, often bilaterally symmetric, may extend to whole lung if severe, often no sign of heart or pulmonary vessel enlargement, history may increase presumptive diagnosis

Hint 18

Front 19

Pulmonary Contusion

Back 19

bleeding/bruising from direct trauma
often unilateral in auto injury, can be bilateral if crushed or bite injury
can occur anywhere lung can be traumatized
interstitial or alveolar pattern, will worse with severity
often have hx or see other radiographic evidence of trauma

Hint 19

Front 20

Bronchial Disease

Back 20

inflammatory diseases of the lower airways (bronchi)
often breed specific name
cats = feline asthma
dogs = chronic bronchitis, allergic pneumonitis
horse = summer pasture associated obstructive pulmonary disease (heaves)
may be allergic in nature or infectious
hx of cough, may have expiratory effort, open mouth breathing (cats)
indicates lower airway predilection of disease, may be combined bronchial and interstitial pattern, cats with asthma may have hyper-inflated lungs

Feline Asthma

Front 21

Pulmonary Hemorrhage

Back 21

could be caused by coagulopathy (rodenticide toxicity, immune mediated causes)
should be differential for abnormal lung apperance when clinical and lab findings suggest bleeding (hemoptysis, bleeding/brusing, prolonged coagulation times)
interstitial or alveolar pattern, one or multiple areas of lung, any distribution any area of lung, no classic apperance

Hint 21

Front 22

Pulmonary Thromboemoblism (PTE)

Back 22

infarcted area of lung secondary to thrombus
often secondary to heartworm disease
can be secondary to hypercoagulable state (Cushing's, DIC, neoplasia, PLN)
typically patient will have acute respiratory distress/dyspnea, typically responds to O2 therapy
Affects focal areas of lung, 2 very different patterns
1. heartworm disease: focal interstitial or alveolar pattern
2. not HWD: hyper lucent lung (decreased vessel size)

Front 23

Lung Nodules

Back 23

2 major differentials:
Neoplasia
Granulomatous disease

most common cause of single soft tissue lung nodule in dogs and cats -> primary lung neoplasia
most common cause of multiple soft tissue lung nodules -> pulmonary metastatic neoplasia

Hint 23

bronchogenic carcinoma with cavitary lung lesion

Front 24

Granulomatous diseases

Back 24

Fungal diseases (endemic areas): Histoplasmosis, blastomycosis, coccidoides
Eosinophilic granulomas: eosinophilic bronchopneumonopathy, allergic pneumonitis, heartworm disease
Parasitic granulomas: paragonimus, heartworms
mineralized nodules are usually benign (old, osteoma); rarely some osteosarcoma or MLO metastasis is partially mineralized

Front 25

Lung Neoplasia

Back 25

nodules (< 3 cm), masses (> 3 cm)
primary: Bronchogenic carcinoma, squamous cell carcinoma, alveolar carcinoma
high differential for nodule in middle or peripheral portion of lung in older cat

Hint 25

mineralized nodules are usually benign (old, osteoma); rarely some osteosarcoma or MLO metastasis is partially mineralized
raise index of suspicion for carcinoma
DDX: granulomatous disease or benign (broncholithiasis, mineralized alveolar mucous glands)

Front 26

Cavitary Lung Lesions

Back 26

Gas filled lung lesion
thin walled: pulmonary bulla (in parenchyma) or bleb (immediately under surface)
-acquired or congenital
-can be incidental, can also rupture and cause pneumothorax

thick walled: neoplasia, abscess, granulmoa(Paragonimus), hemorrhaging bulla(trauma)

Hint 26

Paragonimus granulmoas
dx: fecal flotation

Front 27

Pulmonary lymphoma

Back 27

wide variety of radiographic appearances
-mild to severe unstructured interstitial pattern
-alveolar pattern or bronchial pattern
-nodules, masses
+/- pleural effusion or lymphadenomegaly

severe interstitial pattern

Front 28

Idiopathic Pulmonary Fibrosis of Cats

Back 28

middle age to older cats
can be concurrent with neoplasia
has poor to grave prognosis
wide variety of radiographic appearances: mild to severe interstitial pattern, alveolar or bronchial, nodules, masses
(don't biopsy cat lung)