CXR

Question 1

What to look for to assess the quality of a an Chest X-ray?

Answer 1

Rotation
inspiration
Projection
Exposure

(RIPE)

Question 2

How to tell if rotation is good?

Answer 2

The medial aspect of each clavicle should be equidistant from the spinous processes

Question 3

How to tell if inspiration is good?

Answer 3

5-6 anterior ribs, the lung apices, both costophrenic angles and lateral rib edges should be visible

Question 4

How to tell if projection is good?

Answer 4

if there is no label, then assume it’s a PA. Also, if the scapulae are not projected within the chest, it’s PA.

Question 5

How to tell if exposure is good?

Answer 5

Left hemidiaphragm visible to the spine and vertebrae visible behind heart

Question 6

How to interpret chest x-rays?

Answer 6

ABCDE approach

A - Airways (trachea, carina, bronchi, hilar structures)
B - Breathing (lungs, pleura)
C- Cardiac (heart size, borders)
D - Diaphragm & costophrenic angles
E - everything else (mediastinal contours, aorto-pulmonary contours, valves, pacemakers)

Question 7

What to look for airway?

Answer 7

Deviations of trachea

• The trachea is normally located centrally or just slightly off to the right
• Pushing of trachea – e.g. large pleural effusion / tension pneumothorax
• Pulling of trachea – e.g. consolidation with lobar collapse

Rotation of the patient can give the appearance of a deviated trachea, so as mentioned above, check the clavicles to rule out rotation as the cause.

Hilum

• The hilar are usually the same size, so asymmetry should raise suspicion of pathology
• The hilar point is also a very important landmark; anatomically it is where the descending pulmonary artery intersects the superior pulmonary vein. When this is lost, think of a lesion here
• Bilateral symmetrical enlargement is typically associated with sarcoidosis.
• Unilateral / asymmetrical enlargement may be due to underlying malignancy.

Question 8

What to look for Breathing?

Answer 8

LUNGS:

• Inspect each of the zones of the lung first ensuring that lung markings occupy the entire zone
• Some lung pathology causes symmetrical changes in the lung fields –> pulmonary edema
• Increased airspace shadowing in a given area of the lung field may suggest pathology (e.g. consolidation / malignant lesion).
• The complete absence of lung markings within a segment of the lung field should raise suspicion of pneumothorax.

PLEURAL:
- The pleura are not normally visible in healthy individuals, unless there is an abnormality such as pleural thickening.

Question 9

What to look for Cardiac?

Answer 9

HEART SIZE:

• In a healthy individual the heart should occupy no more than 50% of the thoracic width
• This rule only applies to PA chest x-rays (as AP films exaggerate heart size)*

HEART BORDERS:

• The heart borders may become difficult to distinguish from the lung fields as a result of various pathological processes (e.g. consolidation) which cause increased opacity of the lung tissue.
• Loss of definition of the right heart border is associated with right middle lobe consolidation
• Loss of definition of the left heart border is associated with lingular consolidation

Question 10

What to look for Diaphragm?

Answer 10

Diaphragm:

• The right hemi-diaphragm is in most cases higher than the left in healthy individuals (as a result of the underlying liver)
• The stomach underlies the left hemi-diaphragm and is best identified by the gastric bubble located within it.

Costophrenic recess:

• In a healthy individual the costo-phrenic angles should be clearly visible on a normal CXR as a well defined acute angle.
• Loss of this acute angle (sometimes referred to as costophrenic blunting) can suggest the presence of fluid or consolidation in the area.
• Costophrenic blunting can also occur secondary to lung hyperinflation (seen in diseases such as COPD) as a result of diaphragmatic flattening and subsequent loss of the acute angle.