Chest X-ray Interpretation

By: Lacey Burke, RN, BSN, FNP-S

Know the Normal.

• To have the ability to interpret chest xrays, knowing what’s normal will help you to see when its not.

Steps to Analyze a Chest X-ray

• Side Marker• Projection• Patient Positioning• Rotation• Penetration• Lung Volume• Artifacts

Side Marker

• Ensure correct orientation. • There have been reports of chest drain

insertion on the opposite side to a pneumothorax because of mislabeling.

Projection

• Most films are from posterior to anterior (PA). – X-ray source situated 1.5-1.8 m posterior to the

patient– X-ray plate positioned immediately anterior to

patient’s chest.• Film may be taken anterior to posterior if the

patient has difficulty due to acute illness or general immobility.

Patient Positioning

• PA films taken with patient standing• AP films taken either standing or sitting

position• All films other than those taken PA should be

labeled with the position• Positioning is significant due to the

appearance of air, fluid and blood vessels within the chest.

Air

• Air tends to rise to the highest point within the chest cavity.

• A pneumothorax is most commonly seen at the lung apex in the erect position.

• When the patient lies on the side opposite to the suspected pneumothorax, any air in the pleural cavity will rise along the lateral chest wall.

Fluid

• Pleural fluid usually collects in the lung base and appears dense and opaque, obscuring adjacent structures.

• Fluid usually reaches a higher point along the lateral chest wall than along the mediastium= meniscus sign.

Pulmonary Vessels

Rotation• Rotation should

be minimal.

• Assessed by looking at the medial ends of the clavicles. Distance should be equal from the medial ends of the clavicles and the thoracic spinous processes.

Penetration

• End plates of the lower thoracic vertebral bodies should be just visible through the cardiac shadow.

• Under-penetrated: film looks diffusely opaque• Over-penetrated: film looks diffusely lucent.

Lungs appear blacker than usual and vascular markings are poorly seen.

Lung Volume

• To detect abnormalities-Full inspiration• Diaphragm should be seen at the level of the

8th-10th posterior ribs or the right 6th anterior rib with good inspiration

• Poor inspiration- cause increased opacification of the lungs because of atelectasis

Artifacts

• Common artifacts: – ECG stickers– Patient’s hair and clothing– Hospital bedding

Normal Chest X-ray

Systematic Approach

• Airway• Bones• Circulation• Diaphragm• Review Areas

Airway- Large Airways, Lung, and Pleura

• Check whether trachea is midline or deviated.• Carina lies at the T4 level on expiration and

will move to T6 on inspiration• Right main bronchus has a steeper angle than

the left- in adults.• Lungs divided into lobes by fissures: right lung

has 3 lobes, left lung has 2 lobes.

Bones- Clavicles, Ribs, and Spine

• Assess for fractures and bone destruction– Ribs– Clavicles– Scapulae– Spine

• Ribs and intercostal spaces should be symmetrical.

Circulation-Heart, Mediastinum, and Vascular Markings

Knowledge of the normal anatomical structures that form the mediastinal and cardiac outline helps to detect abnormality. • Left: Superior to inferiorly by the left brachiocephalic

vein, aortic knuckle, left main pulmonary artery, left atrial appendage, and left ventricle.

• Right: right brachiocephalic vein, superior vena cava and right pulmonary artery, right atrium and interior vena cava.

Diaphragm

• Check the shape, height, and angles.• Right diaphragm: approx. 1-3 cm higher than

the left. • Look through diaphragmatic shadow for

pathology of lung bases and pleural reflections for evidence of pleural fluid.

Review Areas• Lines and Tubes: Chest position for complications, ex:

pneumothorax• Central Lines: pass to lower superior vena cava. Should not

enter right atrium• Pulmonary Artery Catheters: should not be wedged into

small branches• Endotracheal Tubes: Tip at least 3 cm above the carina. • Gastric Tubes: pass below the diaphragm and into stomach• Chest drains: Check position. Tip of the tube should lie in

an effective position and not be displaced into lung tissue.

Key Points• Silhouette Sign: Describes loss of normal lung/soft tissue

interface applied to the heart, mediastinum, chest wall and diaphragm.

• Air Bronchogram: Commonly signifies alveolar disease and also atelectasis.

• Consolidation: Result of filling of the alveoli by any cause (Ex: fluid, pus, blood, tumor)

• Pleural Effusion: Greater than 150ml must be present for pleural effusion to be detected on chest X-ray.

Air Bronchogram• If area of lung is consolidated, it becomes dense and white.• If the larger airways are spared, they are relatively low

density “blacker”• Characteristic sign of consolidation

What is this?

Answer:

Pneumonia

What is this?

Answer:

Pneumothorax

What is this?

Answer:

Tuberculosis in the right upper lobe

What is this?

Answer:

Total Atelectasis on RT side.

What is this?

Answer:

Pulmonary Embolism

What is this?

Answer:

Cardiomegaly

What is this?

Answer:

Pleural Effusion

What is this?

Answer

Free Air under the diaphragm

seen in bowel perforation

What is this?

Answer:

Congestive heart failure

Notice the numerous small circular “doughnuts” that represent fluid in

bronchial walls.

And sometimes…Coin

O.R. InstrumentsEarring Back

13-cm steak knife

Resources

• http://www.medscape.com/viewarticle/560163_3