Thorax/lung radiographs

Question 1

what are the indications for thoracic radiography?

Answer 1

metastasis exam
respiratory dysfunction
cardiac disease
esophageal or issues with deglutition
post-surgical complications
establish baseline/normalcy

Question 2

thorax radiographs tend to have _____ inherent contrast. because of this, we have to use _____ kVp and _____ mAs to ________ latitude.

Answer 2

a lot of
high kVp, low mAs, raise latitude

Question 3

if you can, take radiographs during ______ (phase of ventilation)

Answer 3

inspiration

Question 4

ideally, _____ (#) views is best for thoracic radiographs. Which views are these? if you had to do only the bare minimum, what would you do? (small animal)

Answer 4

3
both laterals and VD

bare min: one lateral and VD or DV (2 views)

Question 5

how do you position the animal for a thoracic radiograph? (small animal)

Answer 5

thoracic limbs pulled forward, rib heads/sternebrae/vertebrae superimposed, limbs out of way, avoid patient rotation, hemithorax’s symmetrical

Question 6

Lateral views are better for certain things with thoracic radiographs. Tell me about them

Answer 6

R lateral: cardiac assessment and L pulmonary lobes
L lateral: R pulmonary lobes (asp. pneumonia)

Question 7

what structures can you evaluate on a thoracic radiograph?

Answer 7

resp: lungs/trachea
CV: heart + vessels
pleural space
mediastinum: lymph nodes, esophagus, trachea, vessels
extra thoracic structures: ribs, limb, diaphragm, SQ

Question 8

VD vs DV are better for different things in thoracic radiography. what are they? which is more common?

Answer 8

VD more common
- cranial mediastinum, pleural effusion easier to evaluate
- allows better inflation

DV
- evaluation of caudal lung lobes (met check)
- less resp restriction
- pulmonary edema

Question 9

What is the vertebral heart score? What is the mean?

Answer 9

used to evaluate cardiac size, compares heart to mid-thoracic vertebrae (ID enlargement, monitoring change)
place length of both short and long axes along vertebrae, starting at T4 and going caudally. number of vertebrae along measurement (add together short and long axes) –> VHS

mean: 9.7 ± 0.5 (dogs), <8 (cats)

short axis: middle 3rd of heart (incl. R atrium & L chambers)
long axis: tracheal carina to cardiac apex (incl. L atrium + ventricle)

Question 10

how do LA differ from SA in terms of thoracic radiographs?

Answer 10

only lateral projections, done standing, named by surface adjacent to plate (like other lateral views), may require 4-5 images to acquire entire thorax

Question 11

caudal lobar vessels best seen in _____. cranial lobar vessels best seen in ____ - non-dependent lung best

Answer 11

DV
lateral

Question 12

what are the 3 main pulmonary patterns? how are these defined?

Answer 12

alveolar
bronchial
interstitial (structured/nodular and unstructured)

defined by the primary location of parenchymal disease

Question 13

alveolar patterns arise because … why?

Answer 13

alveoli are no longer air filled
air is replaced by ST opacity/fluid, or collapsed
occurring within alveoli ± extension into bronchi

Question 14

in an alveolar pattern, what could be filling the alveoli?

Answer 14

consolidation - air replaced by fluid/ST (edema, blood, purulent material, neoplasia)

atelectasis - air absent but not replaced, tissue vol is lost = collapse

Question 15

how is an alveolar pattern defined?

Answer 15

air bronchogram
effacement
lobar sign
soft tissue/fluid opaque lung when extensive

not all components required!

Question 16

alveolar patterns are associated with…

Answer 16

pneumonia
cardiogenic (common) and noncardiogenic (less common) pulmonary edema
hemorrhage (traumatic or coagulopathy)
atelectasis

Question 17

if investigating aspiration pneumonia, what should you do?

Answer 17

L lateral to outline R middle lung lobe
retake in 24-48 hours (changes can lag)
pleural effusion = good indicator of progressive disease

Question 18

Tell me the differences between atelectasis and consolidation

Answer 18

atelectasis: increased soft tissue opacity, decrease in lung lobe size, mediastinal shift

consolidation: increase ST opacity, vol of lung lobe maintained, no mediastinal shift

Question 19

what is mediastinal shift? how to see this best on radiograph?

Answer 19

heart shifts toward lung of reduced vol
VD/DV
the atelectasis may be seen on lateral view as an area of increased opacity, or alveolar pattern
if its shift due to a lung mass, or fluid, movement is often contralateral side

Question 20

tell me the differences between pneumonia and non-cardiogenic pulmonary edema on radiograph

Answer 20

pneumonia: ventrally distributed, alveolar pattern, aspiration, viral, fungal

Non-CPE: peripherally distributed, w/o ventral predilection, associated with post-obstructive edema, vasculitis, altitude, neurogenic

Question 21

what is a bronchial pattern? how does it appear radiographically? associated with what?

Answer 21

thickening of bronchi, or fluid/mineralization in tissue immediately adjacent to the bronchi, resulting in progressive conspicuity of smaller bronchi

radiopaque rings (bronchi in cross section) or radiopaque “tram lines” (bronchi in long axis)

associated with inflammatory airway diseases (viral, parasitic, fungal, bacterial, allergic airway diseases, chronic bronchitis, neoplasia)

Question 22

what are the two classifications of interstitial pattern and what do they mean?

Answer 22

structured (nodular): nodules (< 2cm) or masses (> 2cm) – basically things look like nodules/masses, discrete structures
- beware costochondral junctions, end on vessels, osteomata

unstructured: not structured things in lung, lung will overall have increase opacification

Question 23

what are osteomata/osseous metaplasia?

Answer 23

small, 2-4mm pulmonary mineralization/mineral opacity
incidental, benign, usually on periphery of lung

Question 24

what causes unstructured interstitial pattern? why does this happen?

Answer 24

age related scar tissue/fibrosis, infectious (viral, bacterial, fungal, parasitic, FIP, toxoplasmosis), neoplasia (round cell/lymphoma), allergic airway disease, early edema, inhaled toxin and radiation pneumonitis

disease has progressed to involve the parenchyma and connective tissue b/t the bronchi/alveoli/vascular tissue