Chest radiograph assessment using ABCDEFGHI

ABCDEFGHI can be used to guide a systematic interpretation of chest x-rays.

Assessment of quality

The quality of the image can be assessed using the mnemonic PIER:

• position: is this a supine AP file? PA? Lateral?
• inspiration: count the posterior ribs. You should see 10 to 11 ribs with a good inspiratory effect
• exposure: well-exposed films have good lung detail and an outline of the spinal column
• rotation: the space between the medial clavicle and the margin of the adjacent vertebrae should be roughly equal onto each other; look for indwelling lines or objects

Bones and soft tissues

Scan the bones for symmetry, fractures, osteoporosis, or metastaticand lesions. Evaluate the soft tissues for foreign bodies, oedemaswelling, orand subcutaneous air.

Cardiac

Evaluate the heart size: the heart should be <50% of the chest diameter on PA films and <60% on AP films. Check for the heart shape, calcifications, and prosthetic valves.

DiaphragmsDiaphragm

Check diaphragmsthe hemidiaphragms for the position (the right is commonly slightly higher than the left due to the liver) and shape (may be flatflattened bilaterally in asthma or COPD, or unilaterally in case of tension pneumothorax or foreign body aspiration). Look below the diaphragmsdiaphragm for free air.

Effusions

Pleural effusions may be large and obvious or small and subtle. Always check the costophrenic angles for sharpness (blunted angles may indicate small effusions). Check athe lateral film for small posterior effusions (more sensitive for small effusions).

Fields and fissures

Check lung fields for infiltrates (interstitial vs. alveolar), masses, consolidation, air bronchograms, pneumothoraces, and vascular markings. Vessels should taper and should be almost invisible at the lung periphery.

Evaluate the major and minor fissures for thickening or fluid.

Great vessels

Check aortic size and shape and the outlines of pulmonary vessels. The aortic knob should be clearly seen.

Hila and mediastinum

Evaluate the hila for lymphadenopathy, calcifications, and masses. The left hilum is normally higher than the right. Check for widening of the mediastinum (which may indicate aortic dissection in the appropriate clinical setting) and tracheal deviation (which may indicate a mass effect, e.g. from large goitre, or tension pneumothorax). In children, be careful not to mistake the thymus for a mass!

Impression

In most cases, an impression is worth whileworthwhile as it not only forces you to synthesise all the findings together but acts as a double check.