The typical radiation dose to an adult from a chest x-ray is around 0.06 mSv (6 mrem).

Problems identified through chest x-rays

Examples of such problems include but are not limited to:

• Pneumothorax, sometimes tension pneumothorax (though this is usually diagnosed clinically because of its acute nature)
• Rib fracture
• Sternal fracture
• Air space disease/consolidation (e.g. pneumonia)
• Interstitial lung disease (e.g. idiopathic pulmonary fibrosis (IPF), lung cancer, active tuberculosis)
• Cardiac silhouette enlargement - congestive heart failure, pericardial effusion, hypertrophic cardiomyopathies
• Pleural effusion
• Peritonitis
• Hiatal hernia
• Emphysema
• Pulmonary embolism (rarely) - usually CXR is normal
• Dissecting aortic aneurysm (due to trauma, advanced/untreated syphilis, connective tissue disorders)

Chest X-Rays are among the most common films taken, being diagnostic of so many important problems.

Features that are typically examined on a chest X-ray

Every doctor will have a different approach to examining chest X-rays. A commonly used mnemonic for what to look for on a chest X-ray is: It May Prove Quite Right (but) Stop And Be Certain How Lungs Appear:

• I = Identification (name, age, sex, indication for X-ray) by mas
• M = Markers (differentiate left from right - diagnose dextrocardia)
• P = Position - the spinous process of T4 should be between the heads of the clavicle (if it isn't the body is rotated)
• Q = Quality - is the film penetrated properly. In a properly penetrated film the vertebral interspaces should be visible behind the central (cardiac) shadow
• R = Respiration - chest X-rays are typically done with full inspiration
• (but)
• S = Soft tissue - look for subcutaneous emphysema (suggestive of trauma), soft tissue swelling
• A = Abdomen - look for free abdominal air (suggests penetrating trauma, peritonitis, or recent surgery)
• B = Bone - look for fractures (these tend to be at the lateral aspects because of the mechanics - bending moment largest at lateral aspect)
• C = Central shadow (cardiac silhouette) - greater than 50% of lateral distance in frontal view at the diaphragm suggests cardiac enlargement (usually secondary to heart failure) or a pericardial effusion). A widened mediastinum may suggest aortic dissection.
• H = Hila (of the lungs) - can be affected in lung disease, malignant processes and infection (hilar lymphadenopathy).
• L = Lungs - for consolidation, interstitial lung disease (reticular, nodular or reticulonodular), honeycombing, miliary pattern, granulomas, lung masses
• A = Absent structures/Apices of the lung (for pneumothorax)