Pleural Effusions & Pneumothorax

Question 1

Pleural space and mediastinum:

Answer 1

pleural fissures:

• R = 6th ICS, 8th ICS
• L = 4th ICS, 7th ICS

Question 2

What are the 3 Roentgen signs associated with pleural effusion?

Answer 2

1. presence of soft tissue opaque material in the pleural fissures, which widens peripherally and tapers centrally
2. lung lobes retracted from thoracic wall
3. border effacement of the cardiac silhouette and ventral margin of the diaphragm on lateral radiographs

Question 3

How do VD and DV views compare with pleural effusion?

Answer 3

VD - pleural fissure lines

DV - complete effacement of the cardiac silhouette in the ventral thorax —> fluid pools around heart

Question 4

Moderate pleural effusion:

Answer 4

• border effacement of cardiac silhouette and diaphragm
• pleural fissure lines

Question 5

What is seen on these radiographs?

Answer 5

• pleural effusion causing border effacement of the cardiac silhouette and diaphragm
• retraction of lung lobes
• thin line of fat between pericarium and pleural effusion = pericardial stripe sign

Question 6

What is happening in these radiographs?

Answer 6

• retraction of lungs from thoracic wall
• increased opacity of pulmonary parenchyma in ventrocaudal lobes

Question 7

What are restrictive effusions? How does it present on radiographs?

Answer 7

unilateral, chronic, exudative (high protein and cells - pyo, hemo, chylo) that cause thickened visceral pleural surfaces = pleural peel sign

loss of cardiac silhouette and rounded lung lobes

Question 8

What is occurring in these radiographs?

Answer 8

restrictive pleuritis

• R caudal lung lobe rounding
• indentation of pleural visceral surface
• pleural peel = soft tissue opaque line (purple)
• soft tissue opaque nodules (likely pulmonary carcinoma)

Question 9

What is occurring in these radiographs?

Answer 9

• unilateral effusion pushing heart to the left and collapsing lung lobes
• lateral: enlarged pulmonary arteries and veins
• thick margin of caudal lobes

Question 10

What are the 3 Roentgen signs associated with pneumothorax?

Answer 10

1. retraction of lung lobes away from the thoracic walls by gas opacity
2. elevation of the cardiac silhouette away from the sternum
3. separation of lung lobes by the presence of gas in the interlobar fissures

Question 11

Pneumothorax:

Answer 11

notice difference in opacity of pneumothorax (gas) and subcutaneous fat

Question 12

How can small volumes of pneumothorax be differentiated from other effusions?

Answer 12

look for pulmonary vessels —> NOT seen in pneumothorax

ELEVATION (not obscurity) of heart from sternum

Question 13

How are pulmonary contusions appreciated on radiographs?

Answer 13

multifocal alveolar pulmonary patterns = increased opacity

Question 14

Pneumothorax:

Answer 14

• gas opacity lifts cardiac silhouette
• R middle and caudal lung lobes separated/retracted
• absence of pulmonary vasculature peripherally

Question 15

What is a tension pneumothorax?

Answer 15

one-way valve effect, where gas is able to enter the pleural space during inspiration, but unable to leave, which causes pressure to build up with each breath and collapse of lungs and vessels = decreased ventilation and CO

rapidly fatal emergency

Question 16

What are the 4 Roentgen signs associated with tension pneumothorax? What is seen in a unilateral tension pneumothorax?

Answer 16

1. rapid progression of radiographic changes
2. severely collapsed and opaque lung lobes
3. flattened diaphragm
4. overdistended thorax with widened ICS and ribs perpendicular to spine

severe mediastinal shift away from the pneumothorax

Question 17

What is pneumothorax fake out? How can it be differentiated from pneumothorax?

Answer 17

cardiac silhouette elevates away from the sternum in medium and large breed dogs

space not replaced by gas —> lung lobes will not be retracted

Question 18

Pleural effusion vs. pneumothorax:

Answer 18

opacity!