2.1 Normal Chest Radiography

Question 1

List the main projections of chest radiography.

Answer 1

1. Posteroanterior (GOLD STANDARD)
2. Anteroposterior
3. Lordotic and semi-upright
4. Lateral

Question 2

Describe the patient positioning for PA projection.

Answer 2

Usually seen the most in well patients.

Beam penetrates posterior to anterior, with the detector located anterior to the patient.

Question 3

Describe the patient positioning for AP projection.

When could it be used?

Answer 3

Usually seen in unwell patients who are unable to stand and can only lie supine.

Beam penetrates anterior to posterior with the detector located posterior to the patient.

Question 4

Describe the patient positioning for lordotic projection.

What type of imaging artefact would you expect?

Answer 4

Patient can be upright or semi-upright with the beam angled upwards.

This upward angling results in anterior structures appearing more superior than posterior structures.

Question 5

A patient requires a lateral film, but cannot stand.

What view can you consider instead?

Answer 5

You can consider a decubitus view.

• Right decubitus is where the patient lies with their right side down
• Left decubitus is where the patient lies with their left side down

Question 6

Describe what changes you may expect on a CXR taken at a lordotic view compared to the standard PA view.

Answer 6

Question 7

Explain why PA view rather than AP view is gold standard.

What differences are there between the AP and PA projections?

Answer 7

Structures which are further from the cassette are magnified, i.e. in AP view, the cassette is located posterior.

Heart is more anterior, hence it looks larger than normal.

The heart is a very important structure and we want it to be as anatomically accurate as possible, hence we use the PA view instead as it is truer to form.

Furthermore, key structures such as the ribs are more hazy on the AP view.