Table of Contents
Introduction
- Patient: name, DOB, hospital number, age, sex
- Previous films for comparison
Radiograph detail
- Date
- Type (anteroposterior or posteroanterior; erect or supine)
- Adequacy (RIPE)
- Rotation: medial borders of clavicles should be equidistant from nearest spinous process
- Inspiration: at least 5-6 anterior ribs should be visible above diaphragm
- Picture area: lung apices and costodiaphragmatic recesses should be visible; scapulae should be out of the way
- Exposure: vertebral bodies should be just visible through the lower part of the cardiac shadow (overexposure = too black; underexposure = too white)
Interpretation (ABCDE)
Briefly mention obvious abnormalities first
Airway
- Tracheal deviation (away from a pneumothorax or large effusion; towards a collapse)
Breathing
- Lung fields (compare in thirds) – see notes on analysing lung field abnormalities on following page
- Air (pneumothorax)
- Fluid (effusion)
- Consolidation (e.g. due to infection)
- Lobar collapse
- Lesions (e.g. malignancy, abscesses)
- Pleura: look for pleural thickening (pleura not normally visible), and at lung borders for a pneumothorax
- Hilar region: look for lymphadenopathy, masses (malignancy), calcification, bilateral enlargement (sarcoidosis)
Circulation
- Heart size: should be <50% thorax diameter on PA film (cardiomegaly suggests heart failure)
- Heart position (may be displaced if there is lobar collapse or a large effusion)
- Heart shape and borders (right border = right atrium; left border = left ventricle)
- Great vessels: the aortic knuckle should be visible
- Mediastinal width: should be <8cm on PA film (widening may indicate aortic dissection)
Diaphragm
- Position and shape: right usually slightly higher due to liver (flat in COPD)
- Costophrenic angles (blunting indicates effusion)
- Air below diaphragm (abdominal viscus perforation)
Extra things
- Bones and joints: trace around ribs for fractures if clinically suspicious
- Soft tissues: look for swelling, subcutaneous air, masses, calcification of aorta
To complete
- ‘To complete my analysis, I would examine previous films and ascertain the clinical history.’
- Summarise and suggest differentials
Analysing lung field abnormalities
Background knowledge
- Four densities to note on a chest radiograph:
- Bone
- Soft tissue
- Fat
- Air
- Wherever a density changes, a silhouette will be seen
- Consolidated/unaffected lobes may be identified by determining if consolidation is contiguous with:
- Diaphragm = lower lobes
- Cardiac border = middle lobe (right)/lingula (left)
Describing the abnormality
- Density
- Bone/soft tissue/fat/air density
- Uniform (i.e. same shade throughout) or non-uniform (i.e. blotchy)
- Radiograph position
- Left or right
- Zone
- Upper (above 2nd anterior rib)
- Mid (between 2nd and 4th anterior rib)
- Lower (lower than 4th anterior rib)
- Anatomical position (lung parenchyma/pleural space)
- Size
- Borders
For example: ‘There is a non-uniform soft tissue density in the left lower zone. Anatomically, this is in the lower lobe because the left hemi-diaphragm is not visible.’
Diagnosing the abnormality
- Consolidation
- Non-uniform soft tissue density (i.e. blotchy white)
- ‘Air bronchogram’ = visible bronchioles penetrating the consolidated areas (hence, it cannot be collapsed)
- Collapse
- Uniform soft tissue density (i.e. pure white)
- Affected lobe is smaller
- Other structures move towards it into empty space (e.g. heart, other lung lobes, trachea)
- Effusion
- Uniform soft tissue density (i.e. pure white)
- Meniscus sign
- Fluid at lung bases if erect or along posterior thorax if supine
- Pneumothorax
- Normal lung lobes, but they are partially deflated
- Uniform air density (usually at top if erect)
- Seen better on an expiration film
- Look very carefully around pleura!
Common cardiorespiratory conditions with multiple abnormalities
- COPD:
- hyperinflation (>10 posterior ribs visible), flat hemi-diaphragms, decreased lung markings, black lesions (bullae), prominent hila
- Heart failure
- (ABCDE): Alveolar shadowing (‘bat’s wings’ sign), B-lines (interstitial oedema), Cardiomegaly, Diversion of blood to upper lobe, Effusion