How Do I Make Sense of Chest X-Rays? Flashcards
What is the ideal complete chest x-ray?
Erect
Posteroanterior (PA) and lateral
Why is PA preferred to anteroposterior (AP)?
AP magnifies heart
In PA see more of lung fields
What is a projection in x-rays?
Way an x-ray is taken; eg:
- PA
- Lateral
Why is the lateral projection usually left lateral?
Places heart closer to film
What does a left lateral projection mean?
Left side of patient closest to x-ray film
If a patient is sitting upright, is the x-ray considered erect?
Yes
Why are AP chest films usually done?
Patient very unwell/unable to stand
What does a frontal projection describe?
AP
PA
What is a mobile x-ray?
X-ray taken with mobile x-ray machine
Why might a chest x-ray be performed supine?
If patient is very unwell
Not possible/unsafe to sit patient upright
What should you check first in a chest x-ray?
Name Date Other labels - Mobile - AP - Supine - Side marker = L/R
What do you normally see in lung fields as opaque structures?
Pulmonary arteries
Pulmonary veins
Don’t normally see airways
Where are pulmonary vessels larger when seen on an erect chest x-ray?
Towards lung bases due to hydrostatic effect
How do you measure heart size?
Cardiothoracic ratio <50% on PA film with good inspiration
What is the cardiothoracic ratio?
Max cardiac transverse dimension/max transverse lung dimension
When can a normal heart size appear larger on a chest x-ray?
AP - 10% larger
Supine - at least 20% larger
Poor inspiration
Why is a chest x-ray taken on inspiration?
Doesn’t magnify heart size
Allows clearer view of lung fields
What is the effect of a supine film?
Heart looks bigger
Lungs look smaller and congested
How do you gauge lung volume on a chest x-ray?
Count number of anterior ribs visible
Normal = 5-6.5 anterior ribs
How does lung volume change on a chest x-ray in COPD?
Lung volumes expand in sagittal dimension, and top and bottom
What does increased retrosternal lucency mean?
Increased area behind sternum
What does the diaphragm look like in a chest x-ray with hyperinflated lungs?
Flattened
What creates increased opacity in lung fields?
Pleural fluid Collapse of part/all of lung Fluid/cells in airspaces - Oedema - Infective consolidation Fluid/cells in lung interstitium - Oedema - Inflammatory change Tumours/other masses in lung
What does a pleural effusion typically look like?
At base
Meniscus curves up chest wall
Becomes less opaque more superiorly