Revision 7 for 'Chest x-ray - an approach (summary)'

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Chest radiograph (an approach)

Systematic Review

Image quality
  • position: PA erect CXR in full inspiration (semi-erect or supine AP in sick patient)
  • penetration: disc spaces of lower thoracic spine visible
  • rotation: medial ends of the clavicles equidistant from the spinous processes
  • inspiration: 10 to 11 posterior ribs on left side

Assess the heart size and shape on fully inspired PA films

Mediastinum & Hila

Assess the trachea for deviation, narrowing or intraluminal lesions

  • if deviated towards, think volume loss
  • if deviated away, think volume gain

Assess the mediastinal width

  • if widened, think mediastinal mass or vascular abnormality

Check hila position, equal density and normal branching vessels

  • left hilum normally higher than right


Look for areas of increased density comparing the left and right upper, middle and lower zones

  • If increased density, think consolidation, atelectasis, interstitial or nodule/mass

Ensure the heart borders and domes of diaphragm are clearly defined

  • If not, think consolidation +/- collapse
  • localize:  right heart border = RML, left heart border = LUL, right diaphragm dome = RLL, left diaphragm dome = LLL

Assess the vascular markings

  • vessels should taper and be almost invisible at the peripheries
  • lower lobe vessels are larger than upper lobe on erect films

Assess the horizontal fissure for fluid or displacement

  • if displaced upwards, think volume loss of RUL
  • if displaced downwards, think volume loss of RLL

Check the costophrenic and cardiophenic angles

  • If costophrenic angle is blunted, think pleural effusion


Assess shape, position and below for free air

  • right hemidiaphragm should be higher than the left (1-3cm)
  • if flattened, think hyperinflation
  • If free air, think pneumoperitoneum
Thoracic wall & Soft tissue

Scan the ribs, clavicles, scapulae and spine for fractures and bony destruction

Scan the soft tissues for breast shadows, surgical emphysema and foreign bodies

Review areas

Double-check the apices (masses, pneumothorax), hila (masses, lymphadenopathy), retrocardiac zone (lobar collapse, hiatus hernia) and below the diaphragm (tubes and free air)

Finally, always compare to old films


Common pathology

  • most common cause of death due to infectious diseases
  • higher incidence at the extremes of age
  • streptococcus pneumoniae - most common organism
  • homogenous opacification in lobar pattern
  • characteristic air bronchograms and volume loss
  • more: lobar pneumonia
Lobar collapse
  • due to obstruction; luminal (aspiration, mucous plugging), mural (cancer) or extrinsic (mass compression)
  • RUL: right upper medial opacification, elevated horizontal fissure and right hilum
  • LUL: left hemithorax ‘veil-like’ opacity, elevated left hilum
  • RML: horizontal fissure not visible, ill-defined right heart border
  • RLL: right medial basal triangular opacification, depressed right hilum
  • LLL: left retrocardiac triangular opacification, double cardiac contour, depressed left hilum, loss of descending aortic and left medial hemidiaphragmatic outline
  • secondary signs: elevated hemidiaphragm, crowding of ribs and mediastinal shift towards affected side
  • more: lobar collapse
  • air in pleural space
  • categorized as primary spontaneous, secondary spontaneous (underlying lung disease) or iatrogenic/traumatic
  • simple: clearly defined visceral pleural edge paralleling chest wall, peripheral lucency with absent lung markings
  • tension: overexpanded hemithorax, depressed hemidiaphragm, contralateral mediastinal shift
  • more: pneumothorax
Congestive cardiac failure
  • commonly due to left ventricular failure
  • stage 1: redistribution (upper lobe diversion, cardiomegaly)
  • stage 2: interstitial edema (Kerley B lines, peribronchial cuffing, hazy hilar vessels)
  • stage 3: alveolar edema (consolidation, air bronchogram, cottonwool appearance, pleural effusion)
  • more: congestive cardiac failure
Pleural effusions
  • collection of fluid within pleural cavity
  • most commonly due to cardiac failure (transudate) or malignancy (exudate)
  • >200ml fluid required for meniscus at costophrenic angle on erect CXR
  • opaque hemithorax and contralateral mediastinal shift in large volume effusions
  • hydropneumothorax - no meniscus visible
  • more: pleural effusion
Lung carcinoma
  • leading cause of cancer mortality worldwide
  • divided into non-small cell and small cell carcinomas
  • adenocarcinoma most common histological subtype
  • may present as a peripheral rounded or spiculated mass, hilar/perihilar mass, mediastinal widening, lobar collapse or pleural effusion
  • more: lung carcinoma
Pulmonary metastases
  • metastatic spread to lungs via blood or lymphatics
  • most common primaries include breast ca, colorectal ca and renal cell ca
  • peripheral, rounded nodules scattered throughout lungs
  • more: pulmonary metastases
  • gas within peritoneal cavity
  • commonly due to perforated hollow viscus, post-laparoscopy, peritoneal dialysis
  • subdiaphragmatic free gas on erect CXR
  • beware of pseudopneumoperitoneum - basal linear atelectasis and Chilaiditi syndrome
  • more: pneumoperitoneum





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