CXRs

Question 1

How can you tell if a CXR is PA or AP?

Answer 1

PA:

• can see heads of clavicles clearly
• size of heart can be accurately commented on

AP:

• clavicles look flat
• scapulae overlie the image
• large heart

Question 2

How should you interpret a CXR in terms of airways?

Answer 2

• look at trachea, aorta, right and left main bronchus, carina
• HIGH pressure in pleural space; fluid or air can push structures (i.e. trachea) AWAY
• LOW pressure will pull structures (trachea) TOWARDS

Question 3

What would cause high pressure in the pleural space and the trachea to be pushed away?

Answer 3

mass
tension
pneumothorax

Question 4

What would cause low pressure in the pleural space and the trachea to be pulled towards?

Answer 4

lung/lobar collapse
consolidation
fibrosis

Question 5

How should you interpret a CXR in terms of breathing?

Answer 5

look at the upper, middle and lower zones
look for:
- patchy consolidation
- multiple, bilateral opacities (more in upper zone)
- multiple, well demarcated lesions (i.e. coin shape lesions throughout)

Question 6

In what situations might you see:

• patchy consolidation
• multiple, bilateral opacities (more in upper zone)
• multiple, well demarcated lesions

Answer 6

• pneumonia
• pleural effusion
• COPD

Question 7

How should you interpret a CXR in terms of circulation?

Answer 7

• look at aortic notch (is there loss of definition? Aneurysm? Adjacent consolidation?)
• look at right atrium, left ventricle, heart size and borders

Question 8

What size should the heart appear on CXR (PA)?

Answer 8

~50% of thoracic width

if it is greater = cardiomegaly

Question 9

How should you interpret a CXR in terms of diaphragm?

Answer 9

• look for cardiophrenic and costophrenic angle - is there blunting?
• look for air under the diaphragm
• is the right hemidiaphragm pushed up by the liver?
• is the left hemidiaphragm pushed up by the fundus of the stomach?

Question 10

What is it called when there is air under the diaphragm?

Answer 10

pneumoperitoneum

Question 11

What should you look for in a CXR? (apart from airways., breathing, circulation, diaphragm)

Answer 11

• bones (bilateral mid shaft clavicle fracture?)
• borders (visible visceral pleural edge? = traumatic pneumpthorax)
• blunted edges (pleural effusion)
• consolidation (lower lobes? - lower lobe pneumonia)
• lines (kerley B lines, batwing?)
• pacemaker
• artificial valve
• metal work
• NG tube
• stenotomy scar at midline

Question 12

How would heart failure/LVF/pulmonary oedema appear on CXR?

Answer 12

1. upper lobe diversion
2. Kerley B lines
3. batwing sign
4. pleural effusion
   * may see increased cardiac:thoracic ratio