Chest X-rays

Question 1

Describe how x-rays work

Answer 1

An electromagnetic wave of high energy and a very short wavelength
Absorbed to different degrees by different tissues due to density

Question 2

What colour is gas on an x-ray?

Answer 2

Black

Question 3

What colour is fat on an xray?

Answer 3

Grey

Question 4

What colour is calcification on an xray?

Answer 4

Almost white

Question 5

What is the normal projection of a chest x-ray?

Answer 5

PA

Posterior to anterior on the patient

Question 6

When would an AP projection CXR be performed?

Answer 6

If the patient was very unwell

Sitting for this

Question 7

What can’t we comment on in AP CXRs?

Answer 7

Size of the heart

Will be enlarge due to being AP

Question 8

What is the correct inclusion of a chest xray?

Answer 8

Just above the 1st to the costophrenic angles

Past the lateral margins of the ribs

Question 9

How do we check for rotation in a CXR?

Answer 9

Look at the alignment of the spinous processes and the clavicles

Question 10

Where do the lungs come down to an a CXR normally?

Answer 10

Between the 5th and 7th anterior ribs at the mid-clavicular line
We ask the patient to breathe in and hold it

Question 11

What differs on the CXR if the patient gives incomplete inspiration?

Answer 11

Heart looks bigger

Increases lung markings (can see more clearly)

Question 12

What is the penetration and what is adequate for a CXR?

Answer 12

The degree to which to x-rays have passed through the body

Adequate = vertebrae just visible through the heart and the complete left hemidiaphragm is visible

Question 13

What is an artifact on a CXR?

Answer 13

External/iatrogenic material which obstructs view

Eg. Buttons, hair, vascular lines, pacemakers

Question 14

How do we talk about the position of something in the lungs on a CXR?

Answer 14

Talk about zones
Upper, middle and lower
Don’t mention lobes unless you are absolutely sure

Question 15

Describe the things to note/look for when checking the anatomy of a CXR

Answer 15

Trachea - deviated
Hila - left should be slightly higher than right 
Lungs
Diaphragm - sharp angles 
Cardiac contours 
Aortic knuckle on the left
Ribs 
Scapulae
Breasts 
Bowel/stomach gas

Question 16

Should you be able to see the pleura?

Answer 16

No

Unless pleural effusion

Question 17

Describe the systematic approach to CXR evaluation

Answer 17

Patient demographics 
Comment on projection and adequacy (rotation, inspiration and penetration) 
A = airway 
B = breathing 
C= circulation 
D = diaphragm 
E = everything else - bones and soft tissues 
Check review areas

Question 18

What are review areas?

Answer 18

Areas that we commonly miss pathology on CXRs

Question 19

Name the review areas for CXRs

Answer 19

Apices 
Thoracic inlet 
Paratracheal stripe (lymph nodes) 
AP window (between aortic arch and pulmonary artery) 
Hila
Behind heart
Below diaphragm 
Bones
Edges of films

Question 20

What is silhouette sign on a CXR?

Answer 20

Adjacent structures of differing densities form a crisp silhouette
Loss of this contour can locate pathology
‘Loss of the silhouette sign’

Question 21

What things can push the mediastinum away?

Answer 21

Pleural effusions

Tension pneumothorax

Question 22

What things can pull the mediastinum towards?

Answer 22

Collapsed lung

Fibrosis of lung

Question 23

What is a pneumothorax?

Answer 23

Air trapped in the pleural space

Question 24

What is the most common cause of pneumothorax?

Answer 24

Trauma

Laceration of pleura eg from fractured rib

Question 25

In people with which diseases is a spontaneous pneumothorax most likely to occur?

Answer 25

Asthma
emphysema
Marfan’s

Question 26

How do we define a large pneumothorax?

Answer 26

Lung edge > 2 cm from the inner chest wall at the level of the hilum

Question 27

What signs do we see of pneumothorax on a CXR?

Answer 27

Area of blackness
Mediastinal shift away
Depressed hemidiaphragm
Visible pleural edge

Question 28

What is a pleural effusion?

Answer 28

Collection of fluid in the pleural space

Question 29

Describe what you see for a pleural effusion on a CXR

Answer 29

Uniform white areas
Loss of costophrenic angles
Hemidiaphragm obscured
Meniscus

Question 30

Why do we need to be aware of supine CXRs?

Answer 30

Pleural effusions
Fluid will be spread out across the lungs not collecting at the bottom
Grey/hazy

Question 31

What is a lobe lung collapse?

Answer 31

Volume loss within a lung lobe

Question 32

Give some causes of lobar lung collapse

Answer 32

Aspirated foreign material 
Mucus plugging 
Iatrogenic 
Bronchogenic carcinoma 
Compression by adjacent mass

Question 33

What are the general CXR findings for a lobar collapse?

Answer 33

Elevation of diaphragm
Crowding of ribs
Shift of mediastinum towards it
Crowding of pulmonary vessels

Question 34

Define atelectasis

Answer 34

Complete or partial collapse of a lung or lobe of a lung

Question 35

What does it look like if the left lower lobe collapses?

Answer 35

Sail sign

Question 36

What does it look like if the left upper lobe collapses?

Answer 36

Veil sign

Question 37

What does it look like if the right upper lobe collapses?

Answer 37

Pull up the horizontal fissure

Question 38

What does it look like if the right middle lobe collapses?

Answer 38

Cannot see the right heart border

Question 39

Consolidation is filling of the alveoli with …

Answer 39

Pus
Blood
Fluid
Cells

Question 40

What is an air bronchogram?

Answer 40

Consolidation on a CXR leads to air filled bronchi made visible because of opacification of surrounding alveoli

Question 41

What do we call space occupying lesions of less and greater than 3cm?

Answer 41

< 3 cm = nodule

> 3 cm = mass

Question 42

Give some causes of space occupying lesions

Answer 42

Malignancy (primary/mets)
Benign mass
Inflammatory (eg. Rounded pneumonia)
Congenital

Question 43

What is the normal cardiac index?

Answer 43

Ratio of heart to chest < 50%

Must be on a PA image