Chest X-ray

Question 1

Recall the densities on X-radiographs and their radioopacity

Answer 1

From black to white:
- air
- fat
- soft tissue
- bone (cortical bone is whiter)
- metal

Question 2

Break down the doses from various imaging modalities

Answer 2

CXR: 0.05mSv
CT Brain: 2mSv
L Spine XR: 2mSv
Trauma CT: 4-8mSv
PET CT: 4mSv

NOTE: Sievert – absorbed dose
Influenced by many factors including height…
Radiation workers 50mSv/yr

Use wisely, sparingly

Question 3

How can you tell if a patient is rotated?

Answer 3

Distance between spinous processes and clavicular heads should be roughly equal

Question 4

What is the cardiothoracic ratio?

In adults

Answer 4

<50%

Question 5

What could an unexpected white blob indicate?

Answer 5

• infection
• collapsed lobe
• cancer
• rarities

Question 6

What does white-out of the hemi-thorax indicate?

Answer 6

Lung collapse or pneumonectomy

Question 7

What are the eight mediastinal contours?

Answer 7

• aortic knuckle
• main pulmonary artery
• right heart border (RA)
• left heart border (LV)
  **- descending aorta
• right hemidiaphragm
• left hemidiaphragm
• right paratracheal stripe

Question 8

question

Identify the right and left hemidiaphragms

Question 9

Identify the lobes of the lungs

Answer 9

• right: upper, middle, lower
• left: upper, lower

Note:LUL has ‘lingula’ – analogous with middle lobe of right lung

Question 10

What does a fuzzy contour suggest?

Answer 10

means that there is something up against it

Question 11

What additional information can the spinous processes provide?

Question 12

What are the five features that should be identified on a chest x-ray?

Answer 12

• Check rotation (spinous processes and clav. heads)
• Check position of heart (1/3 : 2/3) or cardiac position
• Check heart size (<50% widest diameter)
• Lungs– whiter? blacker?
• tubes (med tubes)
• Look for white blobs (Infection, cancer, other)
• Check the eight cardiomediastinal contours

NOTE:
* Abnormal lung is white on CXR (95% of the time)
* A collapsed lung causes a white hemithorax
- white lung can be infection, cancer, inflammation
* A pneumothorax is black, a bulla is black
* Medical tubes are white – follow them