Pulmonary Parenchyma: Decreased & Increased Opacity Flashcards

1
Q

What are 3 causes of decreased opacity seen on thoracic radiographs?

A
  1. bullae
  2. pneumatocele
  3. hematocele (blood + gas)
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2
Q

What is the main cause of focal/multifocal lobar patterns?

A

regional oligemia (reduction in pulmonary blood volume) —> pulmonary thromboembolism

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3
Q

Where are the regions of focal decreased opacity in this CT scan?

A

decreased opacity adjacent to normal airway

(+ other regions of opacity likely too small to be seen on radiographs)

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4
Q

What are 3 causes of multifocal decreased opacity?

A
  1. cavitated pulmonary nodules - parasites (Paragonimus kellicotti)
  2. pneumatoceles
  3. hematoceles
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5
Q

What is seen in this radiograph?

A

multifocal bullae within right middle and caudal lobes

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6
Q

What is seen in these radiographs?

A
  • mixed opacity, likely due to hematoceles and trauma
  • lung retraction from dorsal body wall = pneumothorax
  • large bulla
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7
Q

What is seen on this radiograph?

A
  • only one perfused region of lungs (right middle/caudal)
  • extremely small vessels
  • PULMONARY THROMBOEMBOLISM: pet is likely cyanotic
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8
Q

What are the 3 most common causes of generalized, decreased opacity of the pulmonary parenchyma?

A
  1. dehydration and hypovolemia
  2. Addison’s disease
  3. severe pulmonary thromboembolism
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9
Q

Generalized decreased opacity:

A
  • extremely small pulmonary vessels
  • small cardiac silhouette and vena cava
  • multiple nodules: neoplasia metastasis, pneumoceles, hematoceles

hepatic mass (HSA) bled out = dehydration and hypovolemia

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10
Q

What is the Roentgen sign associated with pulmonary thromboembolism?

A

regional oligemia (reduction in pulmonary blood volume)

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11
Q

Normal lung anatomy:

A
  • R cranial lobe extends across midline
  • right accessory lobe wraps around caudal vena cava
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12
Q

What 3 things affect normal pulmonary opacity?

A
  1. species and breed - large breed = better inspiratory radiographs
  2. inspiration vs. expiration
  3. pathology present in thorax or abdomen
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13
Q

What 3 things make up the pulmonary parenchyma?

A
  1. blood vessels, capillaries, and pulmonary blood volume
  2. airways
  3. supporting connective tissue

(lung itself is more opaque than air in bronchus)

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14
Q

What interpretation paradigm is used to address increased pulmonary opacity?

A

ASPS

  • Anatomy and distribution: focal, multifocal, generalized, cranioventral, caudodorsal, position in lung lobe (lobar, peripheral, mid-zone, hilar)
  • Shift of the mediastinum
  • Pattern
  • Severity: mild, moderate, severe
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15
Q

How is mediastinal shift described?

A
  • IPSILATERAL: toward the lesion, indicating reduced volume of the pulmonary parenchyma (atelectasis, fibrosis)
  • CONTRALATERAL: away from the lesion, indicating increased volume of the pulmonary parenchyma (mass effect from neoplasia or lung lobe torsion)
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16
Q

What disease is indicated with cranioventral increased pulmonary opacity?

A

pneumonia

  • air bronchogram + megaesophagus
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17
Q

What disease is indicated with caudodorsal increased pulmonary opacity?

A

pulmonary edema

  • large L heart + structured interstitial pattern secondary to edema
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18
Q

Describe the mediastinal shift in the radiographs.

A
  1. normal thorax
  2. ipsilateral rightward mediastinal shift due to atelectasis
  3. contralateral leftward mediastinal shift
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19
Q

What is atelectasis? What 2 things does it cause in radiographs?

A

hypoinflation of the lung lobe (reduced volume of air)

  1. increased soft tissue opacity - mild = unstructured interstitial; severe = alveolar
  2. reduced volume of the lung lobes causes mediastinal shift towards the collapsed lobes because these lobes take up less space in the thorax

(apex to the R, not L)

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20
Q

What is the most common cause of contralateral mediastinal shifts?

A

thoracic mass effect pushes mediastinal structures away from the mass towards the opposite side of the thorax

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21
Q

What 6 pulmonary patterns are recognized?

A
  1. mass
  2. alveolar
  3. bronchial
  4. vascular
  5. structured interstitial (nodules)
  6. unstructured interstitial
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22
Q

How do mass patterns appear on radiographs? How are they named based on size?

A

uniform soft tissue or cavitated mixed gas and soft tissue opacities that are rounded within the lobe or exceeding the expected lobe size, shape, and position

  • > 3cm = mass
  • < 3 cm = nodule
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23
Q

Mass lesion:

A

histiocytic sarcoma, right middle lung lobe

  • exceeded margin, can’t make out right cardiac silhouette
24
Q

Mass lesion:

A

right caudal lung lobe within caudodorsal periphery with no mediastinal shift

  • right lobe more inflated on the left lateral projection, making the lesion better seen in this projection
25
Q

What are 5 possible things are seen on alveolar patterns?

A
  1. uniform soft tissue opacity
  2. presence of air bronchogram**
  3. lobar sign
  4. border effacement of adjacent large structures (silhouette, diaphragm)
  5. border effacement of structures within affected lobe (lobe vessels, bronchi)

3/5 must be present

26
Q

What pattern is seen in this radiograph?

A

alveolar

  • R cranial air bronchogram
27
Q

Pulmonary pattern:

A
28
Q

Lobar sign:

A

increased soft tissue opacity of lung lobe extends to the mardin of the lung lobe and stops abruptly at the junction with the adjacent lobe with a distinct transition between abnormal and normal lobe

  • seen in alveolar pattern!
  • normal R caudal lobe superimposed by severely affected R middle lobe
29
Q

What is a bronchial pattern? Where should it be looked for? What are the most common causes in dogs and cats?

A

rings/donuts (thickened bronchial walls end on) and lines/tramways (long axis) with possible age-relateed mineralization centrally

thin sections of pulmonary parenchyma periphery

  • DOGS = allergic lung disease
  • CATS = asthma
30
Q

What pattern is seen in these radiographs?

A

BRONCHIAL

  • marked airway wall thickening in periphery with donuts and tramways
31
Q

Bronchial pulmonary pattern:

A
32
Q

Bronchial pulmonary pattern with…..

A

mineralization

33
Q

What are 3 causes of vascular pulmonary patterns?

A
  1. enlarged pulmonary arteries - tortuous, blunted = Dirofilaria immitis
  2. enlarged pulmonary veins - left heart failure (dogs)
  3. both enlarged
34
Q

What are 3 causes ofenlarged pulmonary arteries and veins?

A
  1. overcirculation - L to R shunts caused by PDA, VSD, ASD, or arteriovenous fistula
  2. fluid overload
  3. left heart failure in cats
35
Q

What pattern is seen in this radiograph?

A

vascular

  • pulmonary veins located ventral and central relative to the pulmonary arteries
36
Q

What pulmonary pattern is commonly seen with heartworm disease?

A

vascular

  • large, blunted arteries
  • can’t see vessel extend to the end of the lung lobe
37
Q

What are the 2 most common appearances of structured interstitial pulmonary patterns? Where should they be looked for?

A
  1. nodules - less than 3 cm (less than 4-5 mm = not visible)
  2. miliary pattern - small, pinpoint opaque nodules (lymphoma, metastatic carcinoma, fungal disease)

thin sections of the lung over the cardiac silhouette and diaphragm

38
Q

What 2 nodule fake outs look like structured interstitial patterns?

A
  1. osteomas (osseous metaplasia) - small, mineralized pulmonary structures commonly an incidental finding
  2. superficial nodules, ectoparasites, or nipple artefacts causing superimposition over the thorax
39
Q

Nodule fake outs vs structured interstitial pattern:

A

look like structured interstitial patterns

  • smaller-sized mineral opacities able to be seen based on their opacity (NOT size)
  • less opaque, larger soft tissue pulmonary nodule
40
Q

What must be ruled out before calling a pulmonary pattern unstructured interstitial?

A
  • expiration
  • everything else (back door diagnosis)
41
Q

What are unstructured interstitial patterns?

A

ill-defined increase in pulmonary soft tissue opacity with decrease in conspicuity of pulmonary vessels and airway walls

(total loss would be caused by border effacement seen in alveolar patterns)

42
Q

What pattern is seen in this radiograph?

A

unstructured interstitial

  • hard to see pulmonary vessels
  • no air bronchogram
  • caudodorsal - pulmonary edema, cardiac silhouette normal = non-cardiogenic
43
Q

What 2 things cause the increased lung opacity seen in alveolar patterns?

A
  1. filling of alveoli by fluid (edema, hemorrhage) or cells (pneumonia, neoplasia)
  2. collapse of the alveoli/lung lobe (atelectasis)
44
Q

What pattern is seen in these radiographs?

A

alveolar - right middle and cranial lobes

  • increased soft tissue opacity (yellow)
  • lobar sign (blue)
  • air bronchogram (green)
  • border effacement of pulmonary vasculature, body wall, and cardiac silhouette (purple)
45
Q

What pattern is seen in these radiographs?

A

alveolar - caudal subsegment of left cranial lobe

  • increased soft tissue opacity (yellow)
  • lobar sign (blue)
  • air bronchogram (green)
  • border effacement of left thoracic body wall and cardiac silhouette (purple)
46
Q

What pattern is seen in these radiographs?

A

alveolar - focal, ill-defined

  • increased soft tissue opacity defacing pulmonary vasculature (yellow)
  • multiple, small air bronchograms (green)
47
Q

Atelectasis:

A

the left lung lobes (the downward lung lobes) are reduced in volume, with downward/leftward (ipsilateral) shift of the cardiac silhouette. There is also increased soft tissue opacity (an unstructured interstitial pulmonary pattern) throughout the left lung lobes

48
Q

What is happening in this radiograph?

A
  • progressional images - L = initial, R = after sedation and positioned in right lateral recombency for esophageal feeding tube
  • hypoinflated right lobes due to positioning during tube feeding with ispilateral movement on mediastinal structures toward affected lobes
  • apex is now on midline
49
Q

What pattern is seen in these radiographs?

A

bronchial

  • rings (green) and lines (yellow)
  • lungs look busy —> feline asthma!
50
Q

What pattern is seen in this radiograph?

A

vascular - increased opacity in pulmonary parenchyma caused by enlarged pulmonary arteries and/or veins

  • PDA = over-circulation of pulmonary arteries and veins = diffusely distended and enlarged
51
Q

What pattern is seen in this radiograph?

A

structured interstitial

  • pulmonary nodules likely representing pulmonary metastasis
52
Q

What are common nodule fake outs seen in these radiographs?

A
  • end-on pulmonary vessels (green): differentiate based on location and size - more directly over pulmonary vessels and same diamter
  • benign pulmonary osteomas (yellow): small, mineralized and seen most commonly in older dogs on the ventral aspect of the lungs = more opaque than soft tissue

(ALSO: cutaneous nodules/nipples, osteochondral junction mineralization)

53
Q

What is the continuum of unstructured pulmonary pattern like?

A
  • unstructured interstitial pattern may progress to an alveolar pattern
  • alveolar pattern can improve into an unstructured pattern
  • region of alveolar pattern may be surrounded by unstructured interstitial pattern (where the lung is less affected)
54
Q

What pattern is seen in these radiographs?

A

unstructured interstitial

  • L = caudodorsal within right caudal lobe
  • R = diffuse
  • mild, hazy increased soft tissue opacity with blurring and decreased visibility of margins of the pulmonary vessels
55
Q

What pattern is seen in these radiographs?

A

unstructured interstitial - right caudal lobe
progressed to alveolar - left caudal lobe

  • ill-defined, increased soft tissue opacity and decreased visibility of the pulmonary vessels throughout left caudal lung lobe.
  • caudodorsal distribution and left-sided cardiomegaly with enlarged pulmonary veins = cardiogenic pulmonary edema associated with LS CHF