Chest Xray Signs and how to read CXR

Question 1

What are the signs of copd on cxr? (5)

Answer 1

Flattened hemidiaphragms

Nipple shadow (the silhouette of actual nipples)

Smaller heart size

Hyperinflated lung (more than 6 anterior ribs or more than 10 posterior ribs visible at midclav level)

Horizontal ribs

Question 2

What does unilateral air under the diaphragm possibly mean?

Answer 2

Perforated gastric or duodenal ulcer

Perforated small intestine

Perforated large intestine

Question 3

When we see sutures and a metal valve replacement on a cxr, why are the sutures along the sternum?

Answer 3

The sutures hold the sternum in place after it has been cut in to, during the process of replacement of the valve.

Question 4

What is a silhouette sign?

Answer 4

A misnomer, silhouette sign is the pathological loss of a silhouette within the chest.

A silhouette is the outline of a component of the thorax against the air of the lung, e.g. the mediastinum border against the adjacent lungs region

i.e. there are silhouettes of the air within the lungs normally, when we lose any silhouettes that is the silhouette sign

These lines are lost when we have areas of airspace opacities, atelectasis or mass within the lung.

Question 5

If we see an area of abnormal opacity in the apex of a lung, what are our two main differentials?

Answer 5

1. Lung carcinoma
2. TB - often found in the apices of the lungs
3. Benign tumour

Question 6

A patient with suspected lung cancer has a cxr, one entire lung has a “white-out” - what are the two possible reasons for the white-out?

Answer 6

Total pleural effusion of one lung - mediastinum moves away from the white out, pushed by the effusion

Lung collapse (due to bronchi being squeezed shut by the tumour) - mediastinum moves towards the white out, moving in to the region that isn’t giving resistance any more

Question 7

How does asbestos exposure present on a chest X-ray?

Answer 7

Patchy thickenings of the pleura (plaques)
- they can bridge the fissures between the lobes.

Multiple plaques.

Question 8

If we see multiple plaques on a chest X-ray of a person who has been exposed to asbestos, are these mesothelioma?

Answer 8

Chest radiographs are non-specific in differentiating mesothelioma from benign plaques (caused by asbestos).

We may expect:

• reduced volume of the affected hemithorax with an ipsilateral shift of the mediastinum
• rib destruction or extension beyond the lateral/anterior margins of the wall

Question 9

What does pneumonia look like on a cxr?

Answer 9

Unilateral (most commonly)

Dense/patchy consolidation

Hard to differentiate from pleural effusion if it’s in the lower zone

To differentiate which borders correlate to which lobes because this differentiates which lobe is affected.

Important to know:

• Lower lobes abuts the diaphragm
• Right middle lobe abuts right heart border
• Lingula (left upper lobe bronchopulmonary section) abuts the left heart border

Question 10

What are the signs of pleural effusion on CXR?

Answer 10

1. Loss of costophrenic angles (fluid follows gravity)
2. Homogenous opacification
3. Meniscus (fluid level)
4. Bilateral or unilateral

Need to do thoracocentesis if you want to distinguish exudate and transudate - lights criteria

Question 11

What are the signs of HF on CXR?

Answer 11

ABCDEF (Same as seen in COPD, since COPD CAUSES HF)

A - Alveolar oedema (bat wing hilar opacities)

B - Kerley B lines (white horizontal dashes commonly in the lower zone at the lateral areas)

C - Cardiomegaly

D - Dilated upper lobe vessels (pulmonary hypertension)

E - Effusions

F - Fluid in the horizontal fissure

Question 12

What are the signs of a pneumothorax on CXR?

Answer 12

Loss of lung markings in the peripheries of the lung fields

Discrete lung edge (edge of lung markings)

Tracheal/mediastinal deviation away from pneumothorax (If tension-type)

Question 13

What are the signs of lung (lobular) collapse on CXR?

Answer 13

Loss of volume - thorax tries to occupy the space:
1. Intercostal spaces narrow on affected side (no resistance from the lung since it’s absent)

2. Raised hemidiaphragm on affected side
3. Tracheal/mediastinal shift toward the affected side

Left sided:
-Veil sign - whole upper field looks veiled

-Sail sign - sharp line next to left heart border

Right sided:
-Loss of right heart border

Question 14

What are the differentials for numerous calcified nodules on a CXR?

Answer 14

TB

Silicosis

Chronic renal failure

Lymphadenopathy

Chronic pulmonary venous hypertension (HF)

Question 15

What do hilar lymphadenopathies look like on a CXR?

Answer 15

Hilar opacities

Well defined margins (circumscribed)

Multiple opacities

Question 16

Signs of atelactasis on CXR?

Answer 16

Signs of volume loss and tissue filling the space:
Elevated hemidiaphragm on same side
Rib crowding on same side
Mediastinal shift towards it
Pulmonary vessel crowding on same side
Tracheal deviation toward it