Radiography of the Respiratory System

Question 1

Describe the radiological appearance of the normal thorax

Answer 1

Ranging soft tissue opacities of:

Aorta, caudal vena cava, cura, cardiac silhouette, cranial abdomen

Bronchi slight soft tissue opacity with radiolucency when gas filled

Blood vessels soft tissue wall and fluid filled (same opacity) - more radiopaque

Question 2

Outline the lobes of the lungs

Answer 2

Right cranial

Right middle

Right caudal

Accessory

Left cranial

Left middle

Left caudal

Question 3

Explain how common abnormalities in radiological lung patterns occur in the bronchi

Answer 3

Normal:
Can see the walls of larger bronchi (this is usually near the middle of the image - hilar area)
The bronchi exist right to the periphery of the lung lobes – we just can’t see them on radiograph because they become smaller and thinner walled.

Abnormal:
Why we see it: Wall becomes mineralized (opacity is more white) and therefore easier to see
Or wall becomes thicker and therefore is easier to see

Question 4

Explain how common abnormalities in radiological lung patterns occur in the interstitium

Answer 4

Tissue that surrounds the alveoli and vessels – thin
Normal: don’t appreciate it on a radiograph

Abnormal – we see it (it is thickened e.g. haemorrhage or frank nodules)
What we see: Nodules (a soft tissue mass – care not to mistake vessels) or unstructured where there is a diffuse change.

Question 5

Explain how common abnormalities in radiological lung patterns occur in the alveolar

Answer 5

Normal: Alveoli filled with air (gas opacity)

Abnormal: fluid filled or collapsed (soft tissue) but air still in bronchi. Alveoli soft tissue opacity instead of gas opacity. Air bronchograms and border obilterations

Question 6

Explain how common abnormalities in radiological lung patterns occur in the vescular systems

Answer 6

Normal: can see pulmonary vessels (soft tissue wall, filled with fluid (blood) therefore soft tissue opacity.

Abnormal: Bigger or smaller…
Veins are ventral and central [remember this]
Cranial lobar artery and vein should be same diameter as proximal third of the 4th rib

If enlarged – too much circulation in there e.g. fluid overload, left to right shunt
If smaller – too little circulation e.g. hypovolaemia, right to left shunt

Question 7

Describe the principle features of pleural and mediastinal disease

Answer 7

Normal – pleura surrounds the lungs but cannot be appreciated on the normal radiograph. The lungs occupy the entire space - we can see the vessels all the way to the periphery

Abnormal – lungs pulled back from the edge due to contents (air/fluid/mass) in the pleura.

Question 8

Describe the principle features of pleural disease pneumothorax

Answer 8

Lungs being squashed so increased opacity

Air has elevated the heart

Decreased opacity means there is just air (no vessels visible)

Question 9

Describe the principle features of pleural disease pleural effusion

Answer 9

Fluid in the pleural space, increasing opacity disguising the cardiac silhouette and other features

Question 10

Describe the principle features of mediastinal disease

Answer 10

mass - will show as a soft tissue/fluid opacity, may push trachea upwards

Question 11

Trace on specimens the line of pleural reflection from ribcage to diaphragm