35 - Chest X-rays

Question 1

How is an X-ray film made?

Answer 1

• X-ray machine sends x-rays to chest
• Dense/hard tissue e.g bone and fluid stops most X-rays
• Some light lands on photographic plate making a negative picture

Question 2

Uses of CXR

Answer 2

• thorax pathology (lungs, heart, ribs)
• abdominal pathology (pneumoperitoneum)
• Check placement of tubes (endotracheal, chest drain and NG)

Question 3

How do you present a CXR

Answer 3

IORPI 
Identify the patient
Orientate the film
Rotation of film
Penetration 
Inspiration effort

Question 4

What is the difference between AP and PA and which is preferred?

Answer 4

PA is preferred as it is clearer (can see head of clavicle)

AP will show an enlarged heart, flat clavicles and scapula overlies the image

Question 5

How can you tell a CXR is rotated correctly?

Answer 5

The spinous processes should be halfway between the medial ends of the clavicles

Question 6

How many ribs should you see anteriorly and posteriorly?

Answer 6

Anterior - 5 or 7

Posterior - 7-9 (angle downwards)

Question 7

How do you interpret a CXR?

Answer 7

Airways
Breathing
Circulation
Diaphragm
Everything else
(mention the most obvious abnormality first)

Question 8

What pushes the trachea?

Answer 8

High pressure in the pleural space due to fluid or air

Tension pneumothorax

Question 9

What pulls the trachea?

Answer 9

Consolidation
Lobar/lung collapse
Fibrosis

Question 10

What is a pneumothorax

Answer 10

Air in the pleural space

Question 11

What is and open pneumothorax

Answer 11

Trauma, fractured rib – air can come in and out so no pressure build up

Question 12

What is a closed pneumothorax

Answer 12

air can escape into pleural space (pressure is the same)

Question 13

What is a tension pneumothorax

Answer 13

Stab, accidents, Air can only get into the pleural space and accumulate (pressure is higher) forces the lung to collapse lung and compress the mediastinum – Emergency!!

Question 14

How do you treat a tension pneumothorax

Answer 14

• Put a needle into 2IC space
• Chest drain
• Test for via examination
• No breaths sounds – don’t take an x-ray

Question 15

What will pneumonia show on a CXR?

Answer 15

Localised patchy consolidation

Question 16

What will TB show on a CXR

Answer 16

Widespread opacities

if secondary TB - cavity at apex

Question 17

What will cancer lesions show on a CRX

Answer 17

Multiple, well defined lesions

Question 18

How large should the heart be in the cardiothoracic cage

Answer 18

No more than 50%

Question 19

What do you look for in everything else?

Answer 19

Bone fractures
Lines - tubes, ECG leads
Pacemaker
Metalwork
Artificial valves
NG tubes

Question 20

What is pneumoperitoneum

Answer 20

air under the diaphragm (gas in peritoneal cavity)

Pushes up the diaphragm

Question 21

What does heart failure look like on a CXR?

Answer 21

Alveolar shadowing
Kerely B lines
Cardiomegaly 
Divergence to upper lobes
Effusions

Question 22

Pleural effusion on CXR

Answer 22

Costophrenic angles blunted

Question 23

What will a pneumothorax look like on a CXR

Answer 23

lung markings away from edge, mediastinal shift, trachea not central (young kid, sob, chest pain)