Chest X ray Basic ideas.

1. Quality assessment
• Is the film correctly labelled?
• Assessment of exposure quality?
– the vertebral bodies should just be visible
through the heart.
– If the vertebral bodies are not visible, then an
insufficient number of x-ray photons have passed
through the patient to reach the x-ray film.
– if the film appears too ‘black’, then too many
photons have resulted in overexposure of the x-
ray film.

2. • Is the film PA or AP?
• Assessment of patient rotation.
– On a high-quality CXR, the medial ends of both
clavicles should be equidistant from the spinous
process of the vertebral body projected
between the clavicles.

3. • Assessment of adequacy of inspiratory effort
– It is ascertained by counting either the number of
visible anterior or posterior ribs.
– If six complete anterior or ten posterior ribs are
visible then the patient has taken an adequate
inspiratory effort.

4. Assessment of heart size
• The cardiothoracic ratio should be less than
0.5. i.e. A/B < 0.5.
• A cardiothoracic ratio of greater than 0.5 (in a
good quality film) suggests cardiomegaly.

6. Assessment of cardiomediastinal
contour
• Right side:
SVC
RA
• Anterior aspect:
RV
• Cardiac apex:
LV
• Left side:
LV
Left atrial appendage
Pulmonary trunk
Aortic arch.

8. Assessment of the trachea
• Both hilar should be concave. This results from
the superior pulmonary vein crossing the
lower lobe pulmonary artery.
• The point of intersection is known as the hilar
point (HP)

9. Assessment of the trachea
• The trachea is placed usually just to the right
of the midline, but can be pathologically
pushed or pulled to either side, providing
indirect support for an underlying
abnormality.
• The trachea is shown in its normal position,
just to the right of centre.
• The right para-tracheal stripe is clearly seen.

11. Assessment of the diaphragms
• Carefully examine each diaphragm.
• The highest point of the right
diaphragm is usually 1–1.5 cm higher than
that of the left.
• Each costophrenic angle should be sharply
outlined.
• The ‘curvature’ of both hemidiaphragms
should be assessed to identify
diaphragmatic flattening.

15. Assessment of bones and soft tissues
• It is important to scrutinise every rib (from the
anterior to posterior), the clavicles, vertebrae
and the shoulder joints (if they are on the
film).